Changing the past by forgetting
http://arxiv.org/abs/0902.3825 I've written up a small article about the idea that you could end up in a different sector of the multiverse by selective memory erasure. I had written about that possibility a long time ago on this list, but now I've made the argument more rigorous. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-l...@googlegroups.com To unsubscribe from this group, send email to everything-list+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Changing the past by forgetting
Thanks! This is like undoing historical events. If you forget about the fact that dinosaurs ever lived on Earth and there is an alternative history that led to your existence in the multiverse, and you do the memory erasure also in sectors were dinosaurs never lived, you have some nonzero probability of finding yourself on an Earth were the dinosaurs never lived. - Original Message - From: Bruno Marchal marc...@ulb.ac.be To: everything-l...@googlegroups.com Sent: Wednesday, March 11, 2009 06:54 PM Subject: Re: Changing the past by forgetting Nice! I did refer often to the Saibal Mitra backtracking procedure (in immortality discussions). I will take a further look on your paper. If valid, it should work in the comp frame. Amnesia could lead you to the original singularity, which could be a kind of blind spot of universal consciousness, except that with comp such a singularity should looks like a little Mandelbrot set, at first sight, I mean something like a compact view of a universal dovetailing. Bruno On 10 Mar 2009, at 19:55, Saibal Mitra wrote: http://arxiv.org/abs/0902.3825 I've written up a small article about the idea that you could end up in a different sector of the multiverse by selective memory erasure. I had written about that possibility a long time ago on this list, but now I've made the argument more rigorous. http://iridia.ulb.ac.be/~marchal/ --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-l...@googlegroups.com To unsubscribe from this group, send email to everything-list+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Changing the past by forgetting
If we consider measuring the spin of a particle, you could also say that the two possible outcomes just exist and thatthere are two possible future versions of me. There is no meaningful way to associate myself with either of the two outcomes. But then, precisely this implies that after a measurement and forgetting about the result will yield a version of me who is in a similar position as that earlier version of me who had yet to make the measurement. If one could perform measurements in a reversible way, this would be possible to experimentally confirm, as David Deutsch pointed out. You can start with a spin polarized in the x direction. Then you measure the z-component. There then exists a unitary transformation which leads to the observer forgetting about the outcome of the measurement and to the spin to be restored in the original state. The observer does remember having measured the z-component of the spin. Then, measuring the x-component again will yield spin-up with 100% probability, confirming that both branches in which the observer measured spin up and spin down have coherently recombined. This then proves that had the observer measured the z-component, the outcome would not be a priori determined, despite the observer having measured it earlier. So, both branches are real. But then this is true in general, also if the quantum state is of the form: |You[|spin up|rest of the world knows the spin is up + |spin down|rest of the world knows spin is down] although you cannot directly verify it here. But that means that you cannot rule out an alternative theory in which only one of the branches is real when performing a measurement in this case. But if the reality of both branches is accepted, then each time you make a measurement and you don't know the outcome, the outcome is not fixed (proovided, of course, there is indeed more than one branch). - Original Message - From: Jack Mallah jackmal...@yahoo.com To: everything-l...@googlegroups.com Sent: Thursday, March 12, 2009 03:47 AM Subject: Re: Changing the past by forgetting --- On Tue, 3/10/09, Saibal Mitra smi...@zeelandnet.nl wrote: http://arxiv.org/abs/0902.3825 I've written up a small article about the idea that you could end up in a different sector of the multiverse by selective memory erasure. I had written about that possibility a long time ago on this list, but now I've made the argument more rigorous. Saibal, I have to say that I disagree. As you acknowledge, erasing memory doesn't recohere the branches. There is no meaningful sense in which you could end up in a different branch due to memory erasure. You admit the 'effect' has no observable consequences. But it has no unobservable meaning either. In fact, other than what I call 'causal differentiation', which clearly will track the already-decohered branches (so you don't get to reshuffle the deck), there is no meaningful sense in which you will end up in one particular future branch at all. Other than causal differentiation tracking, either 'you' are all of your future branches, or 'you' are just here for the moment and are none of them. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-l...@googlegroups.com To unsubscribe from this group, send email to everything-list+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Changing the past by forgetting
Yes, I agree, and that's then why we cannot do this in practice. The verification of the MWI would have to wait untilk we have artificially intelligent observers implemented by quantum computers. However, ass uming that the MWI is indeed correct, it doesn't matter if you undo the measurement. If you just dump your memory in the nvironment in an irreversible way, you end up in a superposition like: |you[ |universe_1| + |universe_2 ] As far as |you are concerned, it doesn't matter if |universe_1 and |universe_2 differ by one electron state or the state of 10^23 particles: the result of a new measurement is not pre-determined in either case. - Original Message - From: Brent Meeker meeke...@dslextreme.com To: everything-list@googlegroups.com Sent: Sunday, March 15, 2009 08:06 PM Subject: Re: Changing the past by forgetting Saibal Mitra wrote: If we consider measuring the spin of a particle, you could also say that the two possible outcomes just exist and thatthere are two possible future versions of me. There is no meaningful way to associate myself with either of the two outcomes. But then, precisely this implies that after a measurement and forgetting about the result will yield a version of me who is in a similar position as that earlier version of me who had yet to make the measurement. If one could perform measurements in a reversible way, this would be possible to experimentally confirm, as David Deutsch pointed out. You can start with a spin polarized in the x direction. Then you measure the z-component. There then exists a unitary transformation which leads to the observer forgetting about the outcome of the measurement and to the spin to be restored in the original state. The observer does remember having measured the z-component of the spin. Then, measuring the x-component again will yield spin-up with 100% probability, confirming that both branches in which the observer measured spin up and spin down have coherently recombined. This then proves that had the observer measured the z-component, the outcome would not be a priori determined, despite the observer having measured it earlier. So, both branches are real. But then this is true in general, also if the quantum state is of the form: |You[|spin up|rest of the world knows the spin is up + |spin down|rest of the world knows spin is down] You're contemplating reversing three different things: 1) Your knowledge, by forgetting a measurement result. Something that's easy to do. 2) The spin state of a particle. 3) The state of what the rest of the world knows. Because of the entanglement, I don't think you can, in general, reverse the spin state of the particle without reversing what is known about it by the rest of the world. If it was a known state (to someone) the particle can easily be put back in that state. But to do so for a general, unknown state, after a measurement would require invoking time-reversal invariance of the state of whole universe (or at least all of it entangled with the particle spin via the measuring apparatus). Brent Meeker although you cannot directly verify it here. But that means that you cannot rule out an alternative theory in which only one of the branches is real when performing a measurement in this case. But if the reality of both branches is accepted, then each time you make a measurement and you don't know the outcome, the outcome is not fixed (proovided, of course, there is indeed more than one branch). - Original Message - From: Jack Mallah jackmal...@yahoo.com To: everything-list@googlegroups.com Sent: Thursday, March 12, 2009 03:47 AM Subject: Re: Changing the past by forgetting --- On Tue, 3/10/09, Saibal Mitra smi...@zeelandnet.nl wrote: http://arxiv.org/abs/0902.3825 I've written up a small article about the idea that you could end up in a different sector of the multiverse by selective memory erasure. I had written about that possibility a long time ago on this list, but now I've made the argument more rigorous. Saibal, I have to say that I disagree. As you acknowledge, erasing memory doesn't recohere the branches. There is no meaningful sense in which you could end up in a different branch due to memory erasure. You admit the 'effect' has no observable consequences. But it has no unobservable meaning either. In fact, other than what I call 'causal differentiation', which clearly will track the already-decohered branches (so you don't get to reshuffle the deck), there is no meaningful sense in which you will end up in one particular future branch at all. Other than causal differentiation tracking, either 'you' are all of your future branches, or 'you' are just here for the moment and are none of them. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google
Extra explanation
I just send a posting to the FOR list about my article. I did not have the time to reply to everyone on this list previously. Reading the old discussion again, I think that it was suggested that the exact quantum states matter, but they don't. It was only used to illustrate the thought experiment by Deutsch which would allow one to prove that the MWI is correct. This is what I sent to the FOR list: Some time ago I wrote a small article: http://arxiv.org/abs/0902.3825 This was recently featured in New Scientist: http://www.newscientist.com/article/mg20227044.200-avoid-a-future-cataclysm-forget-the-past.html The idea is that an observer can undo things that have already happened by resetting its memory, because when you reset your memory to a previous state, that previous state you are evolving into will be the same in a sector of the multiverse which evolved from that previous state and then was reset for any reason. So, if the reseting is triggered for reason A or reason B, it would lead to the observer ending up in the same state. The outcome of a new measuremnt to find out why the mempory was reset is then not pre-determined. Some details: The word state here refers to the classically describable state of an observer. In the article, I focus on machine observers. The subjective state of the observer is then exactly specified by specifying the ones and zeroes of the bits of the memory. So, I assume that whatever the observer can be aware of is encoded by the classical state of the bits of the computer and not the exact quantum state of the computer. The exact state of the computer has to be specified using a wavefunction of the computer (in fact, the state of the computer will be entangled with the rest of the universe). Then, one can write down any generic quantum state of the universe containing the observer by supplementing the (classical) information stored in the bits by the extra information you need to fully specify the wavefunction of the computer and everything else in the universe. One can then consider the unitary transformations that would represent a memory backup, memory resetting etc. After the memory resetting, you are notified why the memory was reset. Since the relevant things happen in the realm where classical physics applies, the probabilities are the same as what you would find using purely classical reasoning. The interpretation of these probablilites is, however, different from classical physics. When the memory is reset, you evolve to some state while the rest of the inverse will be in some superposition of states in which the memory was reset for various reasons. Then, before finding out why the memory was reset, the outcome of that observation is not pre-determined --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-list@googlegroups.com To unsubscribe from this group, send email to everything-list+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Changing the past by forgetting
That's correct. It is not really irreversible. The point is that it doesn't matter as you end up in a state where the outcome of finding out what happened is not pre-determined. Saibal - Original Message - From: Bruno Marchal marc...@ulb.ac.be To: everything-list@googlegroups.com Sent: Tuesday, April 21, 2009 07:27 PM Subject: Re: Changing the past by forgetting Accepting QM without collapse, I am not sure you can dump your memory in the environment in any truly irreversible way. Bruno On 21 Apr 2009, at 15:22, Saibal Mitra wrote: Yes, I agree, and that's then why we cannot do this in practice. The verification of the MWI would have to wait untilk we have artificially intelligent observers implemented by quantum computers. However, ass uming that the MWI is indeed correct, it doesn't matter if you undo the measurement. If you just dump your memory in the nvironment in an irreversible way, you end up in a superposition like: |you[ |universe_1| + |universe_2 ] As far as |you are concerned, it doesn't matter if |universe_1 and |universe_2 differ by one electron state or the state of 10^23 particles: the result of a new measurement is not pre-determined in either case. - Original Message - From: Brent Meeker meeke...@dslextreme.com To: everything-list@googlegroups.com Sent: Sunday, March 15, 2009 08:06 PM Subject: Re: Changing the past by forgetting Saibal Mitra wrote: If we consider measuring the spin of a particle, you could also say that the two possible outcomes just exist and thatthere are two possible future versions of me. There is no meaningful way to associate myself with either of the two outcomes. But then, precisely this implies that after a measurement and forgetting about the result will yield a version of me who is in a similar position as that earlier version of me who had yet to make the measurement. If one could perform measurements in a reversible way, this would be possible to experimentally confirm, as David Deutsch pointed out. You can start with a spin polarized in the x direction. Then you measure the z-component. There then exists a unitary transformation which leads to the observer forgetting about the outcome of the measurement and to the spin to be restored in the original state. The observer does remember having measured the z-component of the spin. Then, measuring the x-component again will yield spin-up with 100% probability, confirming that both branches in which the observer measured spin up and spin down have coherently recombined. This then proves that had the observer measured the z-component, the outcome would not be a priori determined, despite the observer having measured it earlier. So, both branches are real. But then this is true in general, also if the quantum state is of the form: |You[|spin up|rest of the world knows the spin is up + |spin down|rest of the world knows spin is down] You're contemplating reversing three different things: 1) Your knowledge, by forgetting a measurement result. Something that's easy to do. 2) The spin state of a particle. 3) The state of what the rest of the world knows. Because of the entanglement, I don't think you can, in general, reverse the spin state of the particle without reversing what is known about it by the rest of the world. If it was a known state (to someone) the particle can easily be put back in that state. But to do so for a general, unknown state, after a measurement would require invoking time-reversal invariance of the state of whole universe (or at least all of it entangled with the particle spin via the measuring apparatus). Brent Meeker although you cannot directly verify it here. But that means that you cannot rule out an alternative theory in which only one of the branches is real when performing a measurement in this case. But if the reality of both branches is accepted, then each time you make a measurement and you don't know the outcome, the outcome is not fixed (proovided, of course, there is indeed more than one branch). - Original Message - From: Jack Mallah jackmal...@yahoo.com To: everything-list@googlegroups.com Sent: Thursday, March 12, 2009 03:47 AM Subject: Re: Changing the past by forgetting --- On Tue, 3/10/09, Saibal Mitra smi...@zeelandnet.nl wrote: http://arxiv.org/abs/0902.3825 I've written up a small article about the idea that you could end up in a different sector of the multiverse by selective memory erasure. I had written about that possibility a long time ago on this list, but now I've made the argument more rigorous. Saibal, I have to say that I disagree. As you acknowledge, erasing memory doesn't recohere the branches. There is no meaningful sense
Re: Zuse Symposium: Is the universe a computer? Berlin Nov 6-7
uncompoutable numbers, non countable sets etc. don't exist in first order logic, see here: http://www.earlham.edu/~peters/courses/logsys/low-skol.htm [EMAIL PROTECTED] [EMAIL PROTECTED]: Ah the famous Juergen Schmidhuber! :) Is the universe a computer. Well, if you define 'universe' to mean 'everything which exists' and you're a mathematical platonist and grant reality to infinite sets and uncomputables, the answer must be NO, since if uncomputable numbers are objectively real (strong platonism) they are 'things' and therefore 'part of the universe' which are by definition not computable. But if by 'universe' you just mean 'physical reality' or 'discrete mathematics' or you refuse to grant platonic reality to uncomputables or infinite sets (anti-platonism or weaker platonism) then the answer could be YES, the universe is a computer. Cheers! --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-list@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: testing
The listserver was experiencing a lot of computer pain recently and that prevented it from function normally :) John Mikes [EMAIL PROTECTED]: This is the 3rd time I send a 'test' to myself. I receive list-post on this gmail address, but my mail does not show up, neither here nor on the YAHOO-mail address I unsubscribed from. Am I still on the No e-mail exclusion? Or does the listserve not recognise my mailing? John Mikes --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-list@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Believing in Divine Destiny
The only connection I can think of is as follows. For any given religious text there should exist a universe which best fits those text. Saibal - Original Message - From: Wei Dai [EMAIL PROTECTED] To: everything-list@googlegroups.com Sent: Tuesday, February 27, 2007 11:55 PM Subject: Re: Believing in Divine Destiny A year ago or so Wei Dai put an end to religious discussions on the list. I don't remember if I did that a year ago or not, but I certainly think the current discussion is off-topic. This mailing list is based on the premise that all possible universes exist. Unless someone can think of a connection to this idea, can we please drop this thread? I have also noticed that all of [EMAIL PROTECTED]'s posts are copy-and-pastes from online sources: http://www.islamanswers.net/destiny/recorded.htm http://www.islamanswers.net/unity/understand.htm http://sg.answers.yahoo.com/question/index?qid=20070226110342AAy6SG5 http://www.themodernreligion.com/basic/quran/quran_proof_preservation.htm Copying other people's writings without attribution is plagiarism, which I certainly do not approve of. And aside from that, if anyone wants to reference large amounts of online material, please post a link instead of copying the text. P.S., I find that I am not always able to keep up with all of the discussions on the list. Putting my name in a post is a good way to get my attention, and please always feel free to email me directly with any administrative issues related to the list. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-list@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: How would a computer know if it were conscious?
If it feels bafflement and confusion, then surely it is conscious :) An AI that takes information from books might experience similar qualia we can experience. The AI will be programmed to do certain tasks and it must thus have a notion of what it is doing is ok., not ok, or completely wrong. If things are going wrong and it has to revert what it has just done, it may feel some sort of pain. Just like what happens to us if we pick up something that is very hot. So, I think that there will be a mismatch between the qualia the AI experiences and what it reads about that we experience. The AI won't read the information like we read it. I think it will directly experience it as some qualia, just like we experience information coming in via our senses into our brain. The meaning we associate with the text would not be accessible to the AI, because ultimately that is linked to the qualia we experience. Perhaps what the AI experiences when it is processing information is similar to an animal that is moving in some landscape. Maybe when it reads something then that manifests itself like some object it sees. If it processes information then that could be like picking up that object putting it next to a similar looking object. But if that object represents a text about consciousness then there is no way for the AI to know that. Saibal - Original Message - From: Hal Finney [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Sunday, June 03, 2007 09:52 PM Subject: Re: How would a computer know if it were conscious? Part of what I wanted to get at in my thought experiment is the bafflement and confusion an AI should feel when exposed to human ideas about consciousness. Various people here have proffered their own ideas, and we might assume that the AI would read these suggestions, along with many other ideas that contradict the ones offered here. It seems hard to escape the conclusion that the only logical response is for the AI to figuratively throw up its hands and say that it is impossible to know if it is conscious, because even humans cannot agree on what consciousness is. In particular I don't think an AI could be expected to claim that it knows that it is conscious, that consciousness is a deep and intrinsic part of itself, that whatever else it might be mistaken about it could not be mistaken about being conscious. I don't see any logical way it could reach this conclusion by studying the corpus of writings on the topic. If anyone disagrees, I'd like to hear how it could happen. And the corollary to this is that perhaps humans also cannot legitimately make such claims, since logically their position is not so different from that of the AI. In that case the seemingly axiomatic question of whether we are conscious may after all be something that we could be mistaken about. Hal --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: how to define ASSA (was: The ASSA leads to a unique utilitarism)
1) looks better because there is no unambiguous definition of next. However, I don't understand the shared by everyone part. Different persons are different programs who cannot exactly represent the observer moment of me. As I see it, an observer moment is a snapshot of the universe taken by my brain. The brain simulates a virtual world based on information from the real world. We don't really experience the real world, we just experience this simulated world. Observer moments for observers should refer to the physical states of the virtual world they live in. Since different observers live in different universes which have different laws of physics, these physical states (= qualia) cannot be compared to each other. We can only talk about an absolute measure for programs (simulated by other programs or not)... Citeren Wei Dai [EMAIL PROTECTED]: Russell Standish wrote: This is actually the SSSA, as originally defined by Bostrom. The ASSA is the SSSA applied to next observer moments. I guess there is a bit of confusing on these terms. I did some searching in the mailing list archives to find out how they were originally defined. First of all SSSA was clearly coined by Hal Finney, not Bostrom. Here's Hal Finney on May 18, 1999: Perhaps we need to distinguish a Strong Self-Sampling Assumption, which is like the SSA but instead of discussing observers, it refers to observer-instants. Followed by Bruno Marchal's reply defining RSSA/ASSA: Perhaps we need to distinguish a Strong Self-Sampling Assumption, which is like the SSA but instead of discussing observers, it refers to observer-instants. Useful distinction, indeed. Nevertheless I do think we should also distinguish between a relative strong SSA and a absolute strong SSA. The idea is that we can only quantify the first-person indeterminism on the set of consistent observer-instants extensions. I mean : consistent with the observers memory of its own (first person) past. Actually now I'm not sure what Bruno really meant. I had assumed that ASSA was the same thing as SSSA, only with the clarification that it's not relative. But if Bruno had really meant to define ASSA as SSSA applied to the next observer moment then I have been using the term ASSA incorrectly. So to sum up, there are two possible meanings for ASSA currently. Does anyone else have an opinion on the matter? Here are the competing definitions: 1. You should reason as if your current observer-moment was randomly selected from a distribution that is shared by everyone and independent of your current observations (hence absolute). 2. You should expect your next observer-moment to be randomly selected from a distribution that is shared by everyone and independent of your current observations. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: how to define ASSA
Of course, we all live in the same universe in the sense that we are all simulated by brains that exist in this universe (described approximately by the Standard Model and General Relativity). The problem is how to define the observer moments rigorously at least in principle. It is undeniable that we experience a the world that our brains are simulating and not the real world. We experience the real world only indirectly. If you touch a hot object and burn your finger then you experiencing the pain is really an event that happens in the virtual world simulated by your brain. Your brain simply uses the results of the simulation to compute what action to take in the real world (and the simulation will then be updated accordingly). The burning sensation exists only in the simulated world, not in the real world. Of course, you can infer that the object must have been hot. So, it seems to be more sensible to me to say that an observer moment is itself an entire universe (= program) in some state. This looks equivalent to specifying the exact state a brain is in, but the brain contains more information than is accessible to the observer. We really have to extract the program the brain is running from the brain and use that to define OMs, otherwise an OM becomes an inherently ambiguous concept (e.g. where does the brain end, do the nerves in my feet also count? etc. etc.). One can simply define an observer as some program and look at the entire multiverse to seek out these programs that are in such and such state. Then one adds up all the absolute measures to obtain the total probability that the program is experiencing that state. One would then expect that it is likely that a program defining a human observer is simulated by a brain in a universe described by the Standard Model. citeren Brent Meeker [EMAIL PROTECTED]: Saibal Mitra wrote: 1) looks better because there is no unambiguous definition of next. However, I don't understand the shared by everyone part. Different persons are different programs who cannot exactly represent the observer moment of me. As I see it, an observer moment is a snapshot of the universe taken by my brain. The brain simulates a virtual world based on information from the real world. We don't really experience the real world, we just experience this simulated world. Observer moments for observers should refer to the physical states of the virtual world they live in. Since different observers live in different universes which have different laws of physics, these physical states (= qualia) cannot be compared to each other. How do you know they live in different universes? The great agreement among observers is what leads us to believe in an objective world. It appears that it is more economical (both ontologically and algorithmically) to explain the agreement by supposing there is an objective world as described by physics. In which case the observer moments are derivative from the objective world - that's what makes it a more efficient hypothesis. Brent Meeker --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Request to form 'Social Contract' with SAI
The best thing you could do is to freeze your brain. I think that will preserve the connections between the neurons, although the cells will be destroyed. This will make it easier for a future civilization to regenerate you digitally - Original Message - From: [EMAIL PROTECTED] To: Everything List [EMAIL PROTECTED] Sent: Monday, October 15, 2007 07:17 AM Subject: Re: Request to form 'Social Contract' with SAI On Oct 14, 3:39 am, Bruno Marchal [EMAIL PROTECTED] wrote: Take care, trust yourself and kill all the SAI on the road, to paraphrase a well known Buddhist idea. Either you are sufficiently clever to understand the SAI arguments, showing you are already an SAI yourself, and your message is without purpose, or you are not, in which case, to keep soundness (by lobianity), you better be skeptical, (and not to abide so quick imo). Unless you want to loose your universality, and be a slave, a tool. Bruno http://iridia.ulb.ac.be/~marchal/ Heh. Bruno, I continue to analyse my current (human) condition to try to find a way out of this mess (I'm not a happy bloke). Still considering many possibilities. Given the possibility that super- intelligences do already (or will in the future) exist, there's a chance that a non-interference policy is being/will be pursued, but that there's a way to get their attention - it could be a simple matter of indicating that you are aware of the possibility and requesting to 'sign' a 'social contract'. Get in early now! ;) --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Quantum Immortality = no second law
Citeren nichomachus [EMAIL PROTECTED]: In the description of the quantum immortality gedanken experiment, a physicist rigs an automatic rifle to a geiger counter to fire into him upon the detection of an atomic decay event from a bit of radioactive material. If the many worlds hypothesis is true, the self-awareness of the physicist will continue to find himself alive after any length of time in front of his gun, since there exist parallel worlds where the decay does not occur. This has never been rigorously proven. I can give you some argumetns why the MWI does not imply Quantum Immortality. On a microscopic scale this is analogous to the observing a reality in which the second law of thermodynamics does not hold. for example, since there is a non-zero probability that molecular interactions will result in a decrease in entropy in a particular sealed volume under observation, there exist histories in which this must be observed. This is never observed. Therefore the MWI is shown to be false. This is also not a correct conclusion (if you replace MWI by quantum immortality). --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: Quantum Immortality = no second law
Citeren nichomachus [EMAIL PROTECTED]: In the description of the quantum immortality gedanken experiment, a physicist rigs an automatic rifle to a geiger counter to fire into him upon the detection of an atomic decay event from a bit of radioactive material. If the many worlds hypothesis is true, the self-awareness of the physicist will continue to find himself alive after any length of time in front of his gun, since there exist parallel worlds where the decay does not occur. This has never been rigorously proven. I can give you some argumetns why the MWI does not imply Quantum Immortality. On a microscopic scale this is analogous to the observing a reality in which the second law of thermodynamics does not hold. for example, since there is a non-zero probability that molecular interactions will result in a decrease in entropy in a particular sealed volume under observation, there exist histories in which this must be observed. This is never observed. Therefore the MWI is shown to be false. This is also not a correct conclusion (if you replace MWI by quantum immortality). --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
QTI --- Expanding brains
Yes, I should have mentioned ASSA and RSSA as discussed on this list in the dark ages. I don't buy QTI for quite a few reasons. A model independent objection I have is the following. If you accept QTI, then the information you have about your history will have to grow without limit (if not, then effectively you have a finite lifetime as you can only store a finite amount of information in a finite volume). Your identity must be preserved as your brain continues to expand to make room for all that informaton that must be stored. Now, I find it hard to believe that a superlarge brain the size of the galaxy would still be me. :) - Original Message - From: Russell Standish [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Wednesday, April 16, 2008 03:24 AM Subject: Re: Quantum Immortality = no second law On Wed, Apr 16, 2008 at 02:22:23AM +0200, Saibal Mitra wrote: First off, how is it that the MWI does not imply quantum immortality? MWI is just quantum mechanics without the wavefunction collapse postulate. This then implies that after a measurement your wavefuntion will be in a superposition of the states corresponding to definite outcomes. But we cannot just consider suicide experiments and then say that just because branches of the wavefuntion exist in which I survive, I'll find myself there with 100% probability. The fact that probabilities are conserved follows from unitary time evolution. If a state evolves into a linear combination of states in which I'm dead and alive then the probabilities of all these states add up to 1. The probability of finding myself to be alive at all after the experiment is then less than the probability of me finding myself about to perform the suicide experiment. The probability of me finding myself to be alive after n suicide experiments decays exponentially with n. Therefore I should not expect to find myself having survived many suicide experiments. Note that contrary to what you often read in the popular accounts of the multiverse, the multiverse does not split when we make observations. The most natural state for the entire multiverse is just an eigenstate of the Hamiltonian. The energy can be taken to be zero, therefore the wavefunction of the multiverse satisfies the equation: One should also note that this is the ASSA position. The ASSA was introduced by Jacques Mallah in his argument against quantum immortality, and a number of participants in this list adhere to the ASSA position. Its counterpart if the RSSA, which does imply quantum immortality (provided that the no cul-de-sac conjecture holds), and other list participants adhere to the RSSA. To date, no argument has convincingly demonstrated which of the ASSA or RSSA should be preferred, so it has become somewhat a matter of taste. There is some discussion of this in my book Theory of Nothing. Cheers -- -- -- A/Prof Russell Standish Phone 0425 253119 (mobile) Mathematics UNSW SYDNEY 2052 [EMAIL PROTECTED] Australiahttp://www.hpcoders.com.au -- -- --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to [EMAIL PROTECTED] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~--~~~~--~~--~--~---
Re: objections to QTI
Hi Bruno, Patric has already explained Barbour's position (I didn't read his book). Separating space from time is not very natural... Perhaps one can use a similar method as presented here: http://arxiv.org/abs/math-ph/0008018 to derive the notion of space-time as a first person phenomena. Saibal - Original Message - From: Bruno Marchal [EMAIL PROTECTED] To: Saibal Mitra [EMAIL PROTECTED] Cc: Norman Samish [EMAIL PROTECTED]; everything-list@eskimo.com Sent: Wednesday, June 01, 2005 03:24 PM Subject: Re: objections to QTI Le 01-juin-05, à 15:00, Saibal Mitra a écrit : Hi Norman, I entirely agree with Julian Barbour. A fundamental notion of time would act as a pointer indicating what is real (things that are happening now) and what was real and what will be real. Most of us here on the everything list believe that in a certain sense 'everything exists', so the notion of a fundamental time would be contrary to this idea. I think that that most here on the list would consider time as a first person phenomena Indeed. (SGrz pour those who knows). I would like to know if Norman and Saibal and others agree that there is nothing special with time. Why does not Julian Barbour talk about space-time capsule? (Or does he?) I think space is also a first person phenomena. OK? Bruno http://iridia.ulb.ac.be/~marchal/
Re: Many Pasts? Not according to QM...
- Original Message - From: Hal Finney [EMAIL PROTECTED] To: everything-list@eskimo.com Sent: Friday, June 03, 2005 05:00 AM Subject: Re: Many Pasts? Not according to QM... Stephen Paul King writes: I really do not want to be a stick-in-the-mud here, but what do we base the idea that copies could exist upon? What if I, or any one else's 1st person aspect, can not be copied? If the operation of copying is impossible, what is the status of all of these thought experiments? If, and this is a HUGE if, there is some thing irreducibly quantum mechanical to this 1st person aspect then it follows from QM that copying is not allowed. Neither a quantum state nor a qubit can be copied without destroying the original. According to the Bekenstein bound, which is a result from quantum gravity, any finite sized system can only hold a finite amount of information. That means that it can only be in a finite number of states. If you made a large enough number of systems in every possible state, you would be guaranteed to have one that matched the state of your target system. However you could not in general know which one matched it. Nevertheless this shows that even if consciousness is a quantum phenomenon, it is possible to have copies of it, at the expense of some waste. This is actualy another argument against QTI. There are only a finite number of different versions of observers. Suppose a 'subjective' time evolution on the set of all possible observers exists that is always well defined. Suppose we start with observer O1, and under time evolution it evolves to O2, which then evolves to O3 etc. Eventually an On will be mapped back to O1 (if this never happened that would contradict the fact that there are only a finite number of O's). But mapping back to the initial state doesn't conserve memory. You can thus only subjectively experience yourself evolving for a finite amount of time. Saibal
Re: Observer-Moment Measure from Universe Measure
- Original Message - From: Hal Finney [EMAIL PROTECTED] To: everything-list@eskimo.com Sent: Friday, June 03, 2005 08:10 PM Subject: Observer-Moment Measure from Universe Measure To apply Wei's method, first we need to get serious about what is an OM. We need a formal model and description of a particular OM. Consider, for example, someone's brain when he is having a particular experience. He is eating chocolate ice cream while listening to Beethoven's 5th symphony, on his 30th birthday. Imagine that we could scan his brain with advanced technology and record his neural activity. Imagine further that with the aid of an advanced brain model we are able to prune out the unnecessary information and distill this to the essence of the experience. We come up with a pattern that represents that observer moment. Any system which instantiates that pattern genuinely creates an experience of that observer moment. This pattern is something that can be specified, recorded and written down in some form. It probably involves a huge volume of data. So, now that we have a handle on what a particular OM is, we can more reasonably ask whether a universe instantiates it. Wouldn't it be better to think of OMs as programs just like we think of universes? If you only look at patterns then you get the problem which you later mention like crystals that can represent an OM of a person etc. The patterns one is looking for should be capable of doing computations If I define OMs as a programs (in a particular computational state), then that is the same as saying that OMs are universes in particular states. One can then argue that these universes are very complex and have high measures and are thus likely to be found embedded in simple, low measure, universes. Then one can also address the problem of what qualia actually are. They are 'events' that occur in an OM's universe. In case of persons one can think of the neural network formed by the brain. The events that take place in the universe defined by the neural network are the qualia we experience. So, I think that Wei's interpretation program has to do more than just spot certain patterns localized in time. Similarly if I simulate the solar system on a pc, then this defines a universe in which an event could be that jupiter is at a certain position at a certain time. To 'see' this in terms of the electrons moving through the transistors one has to first 'see' the program. Seeing the program requires one to study the way the object interacts with its environment which means that you have to take it out of the universe and study how it behaves when you expose it to alternative inputs. Saibal
Re: where did the Big Bang come from?
- Original Message - From: Jesse Mazer [EMAIL PROTECTED] To: [EMAIL PROTECTED]; everything-list@eskimo.com Sent: Monday, June 06, 2005 07:53 PM Subject: RE: where did the Big Bang come from? Norman Samish wrote: Norman Samish wrote: And where did this mysterious Big Bang come from? A quantum fluctuation of virtual particles I'm told. On Mon, 6 Jun 2005, Jesse Mazer wrote: Whoever told you that was passing off speculation as fact--in fact there is no agreed-upon answer to the question of what, if anything, came before the Big Bang or caused it. Patrick Leahy wrote: Maybe Norman is confusing the rather more legit idea that the fluctuations in the Big Bang, that explain why the universe is not completely uniform, come from quantum fluctuations amplified by inflation. This is currently the leading theory for the origin of structure, in that it has quite a lot of successful predictions to its credit. Norman Samish writes: Perhaps I didn't express myself well. What I was referring to is at http://www.astronomycafe.net/cosm/planck.html, where Sten Odenwald hypothesizes that random fluctuations in nothing at all led to the Big Bang. This process has been described by the physicist Frank Wilczyk at the University of California, Santa Barbara by saying, 'The reason that there is something instead of nothing is that nothing is unstable.' . . . Physicist Edward Tryon expresses this best by saying that 'Our universe is simply one of those things that happens from time to time.' But as I said, this idea is pure speculation, there isn't any evidence for it and we'd probably need a fully worked-out theory of quantum gravity to see if the idea even makes sense. Jesse This is one of the motivations for believing in a purely mathematical universe. A physical universe can never arise from 'nothing'. If you believe in mathematical reality then there is no mystery. The mathematical model that describes the big bang is eternal. Saibal
Re: Observer-Moment Measure from Universe Measure
I think one should define an observer moment as the instantaneous description of the human brain. I.e. the minimum amount of information you need to simulate the brain of a observer. This description changes over time due to interactions with the environment. Even if there were no interactions with the environment the description would change, but this change is fixed by the original description. So, I see no problem with Hal's way of thinking about OMs Observers are can be thought of as their own descriptions and thus universes in their own right. Observer moments are observers in particular states i.e. their ''personal'' universe being in a certain state. The causal relation between successive states is already defined when we specify which observer we are talking about. i.e., we have already specified the laws of physics for the personal universe of an observer which defines the observer. Specifying the initial state of the personal universes thus suffices. Saibal - Original Message - From: Patrick Leahy [EMAIL PROTECTED] To: Hal Finney [EMAIL PROTECTED] Cc: everything-list@eskimo.com Sent: Wednesday, June 08, 2005 01:04 PM Subject: RE: Observer-Moment Measure from Universe Measure On Tue, 7 Jun 2005, Hal Finney wrote: Jonathan Colvin writes: There's a question begging to be asked, which is (predictably I suppose, for a qualia-denyer such as myself), what makes you think there is such a thing as an essence of an experience? I'd suggest there is no such thing as an observer-moment. I'm happy with using the concept as a tag of sorts when discussing observer selection issues, but I think reifying it is likely a mistake, and goes considerably beyond Strong AI into a full Cartesian dualism. Is it generally accepted here on this list that a substrate-independent thing called an observer moment exists? Here's how I attempted to define observer moment a few years ago: Observer - A subsystem of the multiverse with qualities sufficiently similar to those which are common among human beings that we consider it meaningful that we might have been or might be that subsystem. These qualities include consciousness, perception of a flow of time, and continuity of identity. Observer-moment - An instant of perception by an observer. An observer's sense of the flow of time allows its experience to be divided into units so small that no perceptible change in consciousness is possible in those intervals. Each such unit of time for a particular observer is an observer-moment. So if you don't believe in observer-moments, do you also not believe in observers? Or is it the -moment that causes problems? Obviously, its the -moment. I'm pleased to see that Jonathan and Brent have the same problem with the concept that I do. Being an observer is a process. Slicing it into moments is OK mathematically, where a moment corresponds to a calculus dt (and hence is neither a particular length of time nor an instant). But to regard the observer-state at a particular moment as an isolated entity which is self-aware makes as much sense as regarding individual horizontal slices through a brain as being self-aware. It is the causal relation between successive brain states (incorporating incoming sense data) which constitutes intelligence, and self-awareness is just an epiphenomenon on top of intelligence, i.e. I would not agree that anything can be self-aware but have no intelligence. Paddy Leahy
Re: Observer-Moment Measure from Universe Measure
- Original Message - From: Brent Meeker [EMAIL PROTECTED] To: Saibal Mitra [EMAIL PROTECTED] Sent: Wednesday, June 08, 2005 02:23 PM Subject: RE: Observer-Moment Measure from Universe Measure -Original Message- From: Saibal Mitra [mailto:[EMAIL PROTECTED] Sent: Wednesday, June 08, 2005 1:16 PM To: Patrick Leahy; Hal Finney; [EMAIL PROTECTED]; [EMAIL PROTECTED] Cc: everything-list@eskimo.com Subject: Re: Observer-Moment Measure from Universe Measure I think one should define an observer moment as the instantaneous description of the human brain. I.e. the minimum amount of information you need to simulate the brain of a observer. This description changes over time due to interactions with the environment. Even if there were no interactions with the environment the description would change, but this change is fixed by the original description. That means that, supposing the brain is a classical, the moment cannot be defined by a description of values, omitting rates; just as the path of a ballistic projectile cannot be specified by it location, omitting its velocity. But to include rates means an implicit introduction of time and continuity of OMs. This implies that OMs form causal chains and it makes no sense to talk about the same OM being in two different chains. That's true in an isolated personal universe that is not interacting with an 'outside world'. I could, e.g. take your brain and simulate that on a computer. The evolution equations for your brain are deterministic, so the simulation will describe a unique chain of causal links provided you fix the boundary conditions. If the personal universe is embedded in another universe (like in our case), then the evolution equations will be constantly perturbed. But a lot of the motivation for OMs comes from the brain *not* being classical; from the idea that the brain gets copied into Everett's multiple relative states or MWIs. Decoherence in the brain is very much faster than the neurochemical processes - that's why it's approximately classical. So what is going on when QM predicts different OMs? From Everett's point of view the brain must be treated as part of the QM system and it gets copied - but not by itself. Its description must include its entanglement with the quantum systems observed. So it seems that in either case, classical or quantum, an OM as a description of a brain state, has links outside itself. In the classical case it has casual links in time. In the QM case it has Hilbert space links to what has been observed. I agree. But the entangled state of a brain with the rest of the universe in the MWI corresponds to an ensemble of different worlds such that in each member of the ensemble the brain is in some definite state. So, I see no problem with Hal's way of thinking about OMs Observers are can be thought of as their own descriptions and thus universes in their own right. Observer moments are observers in particular states i.e. their ''personal'' universe being in a certain state. The causal relation between successive states is already defined when we specify which observer we are talking about. i.e., we have already specified the laws of physics for the personal universe of an observer which defines the observer. Specifying the initial state of the personal universes thus suffices. That would hold for a classical brain in a classical universe. But does it in a QM universe? I see a tension between the idea of personal universe and quantum entanglement. I don't see problems here. If you assume that our universe is described by some fundamental laws of physics then those laws of physics also describe our brains. The way a particular brain works is thus fixed. This then defines the personal universe. Entanglement of the brain with another system can only happen if there are interactions with the outside. Even in the classic case these intercations make the evolution of the personal universe nondeterministic. Saibal
RE: Observer-Moment Measure from Universe Measure
- Original Message - From: Brent Meeker [EMAIL PROTECTED] To: Saibal Mitra [EMAIL PROTECTED] Sent: Wednesday, June 08, 2005 02:23 PM Subject: RE: Observer-Moment Measure from Universe Measure -Original Message- From: Saibal Mitra [mailto:[EMAIL PROTECTED] Sent: Wednesday, June 08, 2005 1:16 PM To: Patrick Leahy; Hal Finney; [EMAIL PROTECTED]; [EMAIL PROTECTED] Cc: everything-list@eskimo.com Subject: Re: Observer-Moment Measure from Universe Measure I think one should define an observer moment as the instantaneous description of the human brain. I.e. the minimum amount of information you need to simulate the brain of a observer. This description changes over time due to interactions with the environment. Even if there were no interactions with the environment the description would change, but this change is fixed by the original description. That means that, supposing the brain is a classical, the moment cannot be defined by a description of values, omitting rates; just as the path of a ballistic projectile cannot be specified by it location, omitting its velocity. But to include rates means an implicit introduction of time and continuity of OMs. This implies that OMs form causal chains and it makes no sense to talk about the same OM being in two different chains. That's true in an isolated personal universe that is not interacting with an 'outside world'. I could, e.g. take your brain and simulate that on a computer. The evolution equations for your brain are deterministic, so the simulation will describe a unique chain of causal links provided you fix the boundary conditions. If the personal universe is embedded in another universe (like in our case), then the evolution equations will be constantly perturbed. But a lot of the motivation for OMs comes from the brain *not* being classical; from the idea that the brain gets copied into Everett's multiple relative states or MWIs. Decoherence in the brain is very much faster than the neurochemical processes - that's why it's approximately classical. So what is going on when QM predicts different OMs? From Everett's point of view the brain must be treated as part of the QM system and it gets copied - but not by itself. Its description must include its entanglement with the quantum systems observed. So it seems that in either case, classical or quantum, an OM as a description of a brain state, has links outside itself. In the classical case it has casual links in time. In the QM case it has Hilbert space links to what has been observed. I agree. But the entangled state of a brain with the rest of the universe in the MWI corresponds to an ensemble of different worlds such that in each member of the ensemble the brain is in some definite state. So, I see no problem with Hal's way of thinking about OMs Observers are can be thought of as their own descriptions and thus universes in their own right. Observer moments are observers in particular states i.e. their ''personal'' universe being in a certain state. The causal relation between successive states is already defined when we specify which observer we are talking about. i.e., we have already specified the laws of physics for the personal universe of an observer which defines the observer. Specifying the initial state of the personal universes thus suffices. That would hold for a classical brain in a classical universe. But does it in a QM universe? I see a tension between the idea of personal universe and quantum entanglement. I don't see problems here. If you assume that our universe is described by some fundamental laws of physics then those laws of physics also describe our brains. The way a particular brain works is thus fixed. This then defines the personal universe. Entanglement of the brain with another system can only happen if there are interactions with the outside. Even in the classic case these intercations make the evolution of the personal universe nondeterministic. Saibal - Defeat Spammers by launching DDoS attacks on Spam-Websites: http://www.hillscapital.com/antispam/
Re: Observer-Moment Measure from Universe Measure
- Original Message - From: Brent Meeker [EMAIL PROTECTED] To: Saibal Mitra [EMAIL PROTECTED] Sent: Sunday, June 12, 2005 02:43 AM Subject: RE: Observer-Moment Measure from Universe Measure -Original Message- From: Saibal Mitra [mailto:[EMAIL PROTECTED] Sent: Sunday, June 11, 2000 4:01 PM To: Brent Meeker; :everything-list@eskimo.com Subject: Re: Observer-Moment Measure from Universe Measure - Original Message - From: Brent Meeker [EMAIL PROTECTED] To: Saibal Mitra [EMAIL PROTECTED] Sent: Friday, June 10, 2005 06:41 PM Subject: RE: Observer-Moment Measure from Universe Measure -Original Message- From: Saibal Mitra [mailto:[EMAIL PROTECTED] Sent: Friday, June 10, 2005 11:39 PM To: Brent Meeker; everything Subject: Re: Observer-Moment Measure from Universe Measure - Original Message - From: Brent Meeker [EMAIL PROTECTED] To: Saibal Mitra [EMAIL PROTECTED] Sent: Wednesday, June 08, 2005 02:23 PM Subject: RE: Observer-Moment Measure from Universe Measure -Original Message- From: Saibal Mitra [mailto:[EMAIL PROTECTED] Sent: Wednesday, June 08, 2005 1:16 PM To: Patrick Leahy; Hal Finney; [EMAIL PROTECTED]; [EMAIL PROTECTED] Cc: everything-list@eskimo.com Subject: Re: Observer-Moment Measure from Universe Measure I think one should define an observer moment as the instantaneous description of the human brain. I.e. the minimum amount of information you need to simulate the brain of a observer. This description changes over time due to interactions with the environment. Even if there were no interactions with the environment the description would change, but this change is fixed by the original description. That means that, supposing the brain is a classical, the moment cannot be defined by a description of values, omitting rates; just as the path of a ballistic projectile cannot be specified by it location, omitting its velocity. But to include rates means an implicit introduction of time and continuity of OMs. This implies that OMs form causal chains and it makes no sense to talk about the same OM being in two different chains. That's true in an isolated personal universe that is not interacting with an 'outside world'. I could, e.g. take your brain and simulate that on a computer. The evolution equations for your brain are deterministic, so the simulation will describe a unique chain of causal links provided you fix the boundary conditions. If the personal universe is embedded in another universe (like in our case), then the evolution equations will be constantly perturbed. But a lot of the motivation for OMs comes from the brain *not* being classical; from the idea that the brain gets copied into Everett's multiple relative states or MWIs. Decoherence in the brain is very much faster than the neurochemical processes - that's why it's approximately classical. So what is going on when QM predicts different OMs? From Everett's point of view the brain must be treated as part of the QM system and it gets copied - but not by itself. Its description must include its entanglement with the quantum systems observed. So it seems that in either case, classical or quantum, an OM as a description of a brain state, has links outside itself. In the classical case it has casual links in time. In the QM case it has Hilbert space links to what has been observed. I agree. But the entangled state of a brain with the rest of the universe in the MWI corresponds to an ensemble of different worlds such that in each member of the ensemble the brain is in some definite state. So, I see no problem with Hal's way of thinking about OMs Observers are can be thought of as their own descriptions and thus universes in their own right. Observer moments are observers in particular states i.e. their ''personal'' universe being in a certain state. The causal relation between successive states is already defined when we specify which observer we are talking about. i.e., we have already specified the laws of physics for the personal universe of an observer which defines the observer. Specifying the initial state of the personal universes thus suffices. That would hold for a classical brain in a classical universe. But does it in a QM universe? I see a tension between the idea of personal universe and quantum entanglement. I don't see problems here. If you assume that our universe is described by some fundamental laws of physics then those laws of physics also describe our brains. The way a particular brain works is thus fixed. This then defines the personal universe. There seems to be a big jump between those last two sentences. Defining the laws
RE: Observer-Moment Measure from Universe Measure
- Original Message - From: Brent Meeker [EMAIL PROTECTED] To: Saibal Mitra [EMAIL PROTECTED] Sent: Friday, June 10, 2005 06:41 PM Subject: RE: Observer-Moment Measure from Universe Measure -Original Message- From: Saibal Mitra [mailto:[EMAIL PROTECTED] Sent: Friday, June 10, 2005 11:39 PM To: Brent Meeker; everything Subject: Re: Observer-Moment Measure from Universe Measure - Original Message - From: Brent Meeker [EMAIL PROTECTED] To: Saibal Mitra [EMAIL PROTECTED] Sent: Wednesday, June 08, 2005 02:23 PM Subject: RE: Observer-Moment Measure from Universe Measure -Original Message- From: Saibal Mitra [mailto:[EMAIL PROTECTED] Sent: Wednesday, June 08, 2005 1:16 PM To: Patrick Leahy; Hal Finney; [EMAIL PROTECTED]; [EMAIL PROTECTED] Cc: everything-list@eskimo.com Subject: Re: Observer-Moment Measure from Universe Measure I think one should define an observer moment as the instantaneous description of the human brain. I.e. the minimum amount of information you need to simulate the brain of a observer. This description changes over time due to interactions with the environment. Even if there were no interactions with the environment the description would change, but this change is fixed by the original description. That means that, supposing the brain is a classical, the moment cannot be defined by a description of values, omitting rates; just as the path of a ballistic projectile cannot be specified by it location, omitting its velocity. But to include rates means an implicit introduction of time and continuity of OMs. This implies that OMs form causal chains and it makes no sense to talk about the same OM being in two different chains. That's true in an isolated personal universe that is not interacting with an 'outside world'. I could, e.g. take your brain and simulate that on a computer. The evolution equations for your brain are deterministic, so the simulation will describe a unique chain of causal links provided you fix the boundary conditions. If the personal universe is embedded in another universe (like in our case), then the evolution equations will be constantly perturbed. But a lot of the motivation for OMs comes from the brain *not* being classical; from the idea that the brain gets copied into Everett's multiple relative states or MWIs. Decoherence in the brain is very much faster than the neurochemical processes - that's why it's approximately classical. So what is going on when QM predicts different OMs? From Everett's point of view the brain must be treated as part of the QM system and it gets copied - but not by itself. Its description must include its entanglement with the quantum systems observed. So it seems that in either case, classical or quantum, an OM as a description of a brain state, has links outside itself. In the classical case it has casual links in time. In the QM case it has Hilbert space links to what has been observed. I agree. But the entangled state of a brain with the rest of the universe in the MWI corresponds to an ensemble of different worlds such that in each member of the ensemble the brain is in some definite state. So, I see no problem with Hal's way of thinking about OMs Observers are can be thought of as their own descriptions and thus universes in their own right. Observer moments are observers in particular states i.e. their ''personal'' universe being in a certain state. The causal relation between successive states is already defined when we specify which observer we are talking about. i.e., we have already specified the laws of physics for the personal universe of an observer which defines the observer. Specifying the initial state of the personal universes thus suffices. That would hold for a classical brain in a classical universe. But does it in a QM universe? I see a tension between the idea of personal universe and quantum entanglement. I don't see problems here. If you assume that our universe is described by some fundamental laws of physics then those laws of physics also describe our brains. The way a particular brain works is thus fixed. This then defines the personal universe. There seems to be a big jump between those last two sentences. Defining the laws of physics may define the *way* a brain works - but not its content, not the specifics of its processes - and the same for a universe. Entanglement of the brain with another system can only happen if there are interactions with the outside. Sure, and there must be such interactions according to what we know of physics. Even in the classic case these intercations make the evolution of the personal universe nondeterministic. Right. But in that case on observer moment, defined as: ...one should define an observer moment as the instantaneous
Re: more torture
Because no such thing as free will exists one has to consider three different universes in which the three different choices are made. The three universes will have comparable measures. The antropic factor of 10^100 will then dominate and will cause the observer to find himself having made choice b) as one of the 10^100 copies in the minute without torture. Saibal - Defeat Spammers by launching DDoS attacks on Spam-Websites: http://www.hillscapital.com/antispam/ - Original Message - From: Stathis Papaioannou [EMAIL PROTECTED] To: everything-list@eskimo.com Sent: Monday, June 13, 2005 01:00 PM Subject: more torture I have been arguing in recent posts that the absolute measure of an observer moment (or observer, if you prefer) makes no possible difference at the first person level. A counterargument has been that, even if an observer cannot know how many instantiations of him are being run, it is still important in principle to take the absolute measure into account, for example when considering the total amount of suffering in the world. The following thought experiment shows how, counterintuitively, sticking to this principle may actually be doing the victims a disservice: You are one of 10 copies who are being tortured. The copies are all being run in lockstep with each other, as would occur if 10 identical computers were running 10 identical sentient programs. Assume that the torture is so bad that death is preferable, and so bad that escaping it with your life is only marginally preferable to escaping it by dying (eg., given the option of a 50% chance of dying or a 49% chance of escaping the torture and living, you would take the 50%). The torture will continue for a year, but you are allowed one of 3 choices as to how things will proceed: (a) 9 of the 10 copies will be chosen at random and painlessly killed, while the remaining copy will continue to be tortured. (b) For one minute, the torture will cease and the number of copies will increase to 10^100. Once the minute is up, the number of copies will be reduced to 10 again and the torture will resume as before. (c) the torture will be stopped for 8 randomly chosen copies, and continue for the other 2. Which would you choose? To me, it seems clear that there is an 80% chance of escaping the torture if you pick (c), while with (a) it is certain that the torture will continue, and with (b) it is certain that the torture will continue with only one minute of respite. Are there other ways to look at the choices? It might be argued that in (a) there is a 90% chance that you will be one of the copies who is killed, and thus a 90% chance that you will escape the torture, better than your chances in (c). However, even if you are one of the ones killed, this does not help you at all. If there is a successor observer moment at the moment of death, subjectively, your consciousness will continue. The successor OM in this case comes from the one remaining copy who is being tortured, hence guaranteeing that you will continue to suffer. What about looking at it from an altruistic rather than selfish viewpoint: isn't it is better to decrease the total suffering in the world by 90% as in (a) rather than by 80% as in (c)? Before making plans to decrease suffering, ask the victims. All 10 copies will plead with you to choose (c). What about (b)? ASSA enthusiasts might argue that with this choice, an OM sampled randomly from the set of all possible OM's will almost certainly be from the one minute torture-free interval. What would this mean for the victims? If you interview each of the 10 copies before the minute starts, they will tell you that they are currently being tortured and they expect that they will get one minute respite, then start suffering again, so they wish the choice had been (c). Next, if you interview each of the 10^100 copies they will tell you that the torture has stopped for exactly one minute by the torture chambre's clock, but they know that it is going to start again and they wish you had chosen (c). Finally, if you interview each of the 10 copies for whom the torture has recommenced, they will report that they remember the minute of respite, but that's no good to them now, and they wish you had chosen (c). --Stathis Papaioannou _ Express yourself instantly with MSN Messenger! Download today - it's FREE! http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/
Re: more torture
- Original Message - From: Stathis Papaioannou [EMAIL PROTECTED] To: [EMAIL PROTECTED]; everything-list@eskimo.com Sent: Tuesday, June 14, 2005 08:06 AM Subject: Re: more torture Saibal Mitra writes: Because no such thing as free will exists one has to consider three different universes in which the three different choices are made. The three universes will have comparable measures. The antropic factor of 10^100 will then dominate and will cause the observer to find himself having made choice b) as one of the 10^100 copies in the minute without torture. But what will happen to the observer when the minute is up? --Stathis Pretending that these three universes are all that exists, what will happen is that the OM will find himself being another one of the 10^100 copies. The copy survives with memory loss. Saibal
Re: more torture
- Original Message -
From: Stathis Papaioannou [EMAIL PROTECTED]
To: [EMAIL PROTECTED]; everything-list@eskimo.com
Sent: Tuesday, June 14, 2005 05:26 PM
Subject: Re: more torture
Saibal Mitra writes:
Because no such thing as free will exists one has to consider three
different universes in which the three different choices are made.
The
three
universes will have comparable measures. The antropic factor of
10^100
will
then dominate and will cause the observer to find himself having made
choice
b) as one of the 10^100 copies in the minute without torture.
But what will happen to the observer when the minute is up?
--Stathis
Pretending that these three universes are all that exists, what will
happen
is that the OM will find himself being another one of the 10^100 copies.
The
copy survives with memory loss.
Saibal
In what sense can the copy (or anything) become another copy with memory
loss? It is almost as if you are postulating a soul, which flies from one
body to another, and somehow contains the original person's identity so
that
it survives memory loss. What is required for an observer moment OM_1 at
time t1 to become the next observer moment at time t2 is that at least
one
successor OM exist with time stamp t2, a belief that he is the same person
as OM_1, and memories of OM_1 up to time t2. If several such OM's exist
{OM_2.1, OM_2.2, OM_2.3...} then either one may be the successor, with
probability determined by the measure of OM_2.n relative to the measure of
the whole set. Amazingly, being completely swamped with other OM's of
various types and vintages, more or less closely related to OM_1, makes
absolutely no difference to the process, because the OM's don't need to
find each other and lock arms, all they need to do is *exist*, anywhere
in
the multiverse, related in the way I have described. This is somewhat
analogous to the fact that the integer 56 is always followed by the
integer
57, even though there are lots and lots of other integers everywhere
amongst
which these two could get lost.
--Stathsi Papaioannou
I'm certainly not postulating a soul. All I'm saying is that all OMs are
real and there is no preference for one over another. Each OM will feel that
he is the successor of a previous one. If an OM checks if he is a typical
creature in the universe, he will find with large probability that this is
indeed the case.
Your proposal about time evolution ignores memory loss. How to assign
probabilities to OM_2.1, OM_2.2, etc. if they don't remember everything
about OM_1? Real people's memories are not perfect. So, you would have to
admit memory loss to make your proposal work in practice. And unless you
believe that QTI makes you immune from Alzheimer's you would have to admit
an arbitrary large amount of memory loss.
So, to me the notion of a successor doesn't make sense in general. You can
always define a set of successors of OM_1 irrespective of measure by saying
that members of that set remember being OM_1. But then there also exists
successors of me with perfect memory but with very small measures. I could
e.g. arise accidentally in a simulation performed by aliens and that
simulation could be a more perfect continuation (memory wise) of my present
OM.
These considerations have led me to believe that one should abandon any
fundamental idea of successors altogether. OMs just exist and each OM has a
memory of ''previous'' experiences. So, each OM remembers being another OM.
There exists a probability distribution over the set of all OMs which is
fixed by the laws of physics. OMs thus ''always'' exist and this is a form
of immortality. In your example of 10^100 copies almost all OMs are one of
these copies. What happens to such an OM when the minute is up? Nothing
really happens. All the OMs are ''static'' mathematical entities.
Saibal
Re: copy method important?
You ca still create two identical systems starting from another system. E.g. in stimulated emission two photons are created in the same state. Another example is a Bose Einstein condensate, in which all the atoms are in the same state. Note that you can still teleport an unknown quantum state despite Heisenberg's uncertainty principle (you do this without measuring the state). It can be shown that you can't copy an unknown quantum state, because that would violate the Schrodinger equation. Saibal - Defeat Spammers by launching DDoS attacks on Spam-Websites: http://www.hillscapital.com/antispam/ - Original Message - From: Norman Samish [EMAIL PROTECTED] To: everything-list@eskimo.com Sent: Saturday, June 18, 2005 08:36 PM Subject: Re: copy method important? I'm no physicist, but doesn't Heisenberg's Uncertainty Principle forbid making exact quantum-level measurements, hence exact copies? If so, then all this talk of making exact copies is fantasy. Norman Samish ~ - Original Message - From: rmiller [EMAIL PROTECTED] To: Stathis Papaioannou [EMAIL PROTECTED]; [EMAIL PROTECTED]; everything-list@eskimo.com Sent: Saturday, June 18, 2005 10:05 AM Subject: copy method important? All, Though we're not discussing entanglement per se, some of these examples surely meet the criteria. So, my thought question for the day: is the method of copying important? Example #1: we start with a single marble, A. Then, we magically create a copy, marble B--perfectly like marble B in every way. . .that is, the atoms are configured similarly, the interaction environment is the same--and they are indistinguishable from one another. Example #2: we start with a single marble A. Then, instead of magically creating a copy, we search the universe, Tegmarkian-style, and locate a second marble, B that is perfectly equivalent to our original marble A. All tests both magically avoid QM decoherence problems and show that our newfound marble is, in fact, indistinguishable in every way from our original. Here's the question: Are the properties of the *relationship* between Marbles A and B in Example #1 perfectly equivalent to those in Example #2? If the criteria involves simply analysis of configurations at a precise point in time, it would seem the answer must be yes. On the other hand, if the method by which the marbles were created is crucial to the present configuration, then the answer would be no. R. Miller -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.323 / Virus Database: 267.7.8/22 - Release Date: 6/17/2005
Re: Reference class (was dualism and the DA)
- Original Message - From: Jonathan Colvin [EMAIL PROTECTED] To: 'Russell Standish' [EMAIL PROTECTED] Cc: 'EverythingList' everything-list@eskimo.com Sent: Monday, June 20, 2005 09:52 PM Subject: Reference class (was dualism and the DA) Russell Standish wrote: (JC) If you want to insist that What would it be like to be a bat is equivalent to the question What would the universe be like if I had been a bat rather than me?, it is very hard to see what the answer could be. Suppose you *had* been a bat rather than you (Russell Standish). How would the universe be any different than it is now? If you can answer that question, (which is the key question, to my mind), then I'll grant that the question is meaningful. No different in the 3rd person, very obviously different in the 1st person I don't really know what that means. The only way I can make sense of the question is something like, If I was a bat instead of me (Jonathan Colvin), then the universe would consist of a bat asking the question I'm asking now. That's a counterfactual, a way in which the universe would be objectively different. It wouldn't be counterfactual, because by assumption bats ask this question of themselves anyway. Hence there is no difference in the 3rd person. The 1st person experience is very different though. There are only 1st person counterfactuals. That's quite an assumption. *Do* all conscious things ask this question of themselves? Babies don't. Senile old people don't. I'm not sure that medieval peasants ever thought to ask this question, or pre-literate cavemen. I definitely acknowledge the distinction between 1st and 3rd person. This is not the same as duality, which posits a 3rd person entity (the immaterial soul). This is, I think, the crux of the reference class issue with the DA. My (and your) reference class can not be merely conscious observers or all humans, but must be something much closer to someone (or thing) discussing or aware of the DA). I don't think this is a meaningful reference class. I can still ask the question why am I me, and not someone else without being aware of the DA. All it takes is self-awareness IMHO. You *could* certainly. Perhaps it is important as to whether you actually *do* ask that question (and perhaps it should be in the context of the DA). I note that this reference class is certainly appropriate for you and me, and likely for anyone else reading this. This reference class certainly also invalidates the DA (although immaterial souls would rescue it). But at this point, I am, like Nick Bostrom, tempted to throw my hands up and declare the reference class issue pretty much intractable. Jonathan Colvin Incidently, I think I may have an answer to my Why am I not Chinese criticism, and the corresponding correction to Why am I not an ant seems to give the same answer as I originally proposed. I'd be interested to hear it. Here's something else you could look at...calculate the median annual income for all humans alive today (I believe it is around $4,000 /year), compare it to your own, and see if you are anyway near the median. I predict that the answer for you (and for anyone else reading this), is far from the median. This result is obviously related to the why you are not Chinese criticism, and is, I believe, the reason the DA goes astray. Jonathan Colvin I don't think so, because most people on Earth are not Chinese. The correct refutation of the Doomsday Paradox was given by D. Dieks and involves the Self Indicating Axiom. The definition of the reference class defines the set of observers that you consider to be you. The DA involves applying Bayes's theorem and to do that correctly you have then to use the correct a priori probability which is also fixed by the choice of the reference class. The two effects cancel and there is no Doomsday Problem. This is all explained here: http://arxiv.org/abs/gr-qc/0009081 Saibal - Defeat Spammers by launching DDoS attacks on Spam-Websites: http://www.hillscapital.com/antispam/
Re: Measure, Doomsday argument
- Original Message - From: Quentin Anciaux [EMAIL PROTECTED] To: everything-list@eskimo.com Sent: Monday, June 20, 2005 11:37 PM Subject: Measure, Doomsday argument Hi everyone, I have some questions about measure... As I understand the DA, it is based on conditionnal probabilities. To somehow calculate the chance on doom soon or doom late. An observer should reason as if he is a random observer from the class of observer. The conditionnal probabilities come from the fact, that the observer find that he is the sixty billions and something observer to be born. Discover this fact, this increase the probability of doom soon. The probability is increased because if doom late is the case, the probability to find myself in a universe where billions of billions of observer are present is greater but I know that I'm the sixty billions and something observer. This is a false argument see here: http://arxiv.org/abs/gr-qc/0009081 To calculate the conditional probability given the birthrank you have you must use Bayes' theorem. You then have to take into account the a priori probability for a given birthrank. If you could have been anyone of all the people that will ever live, then you must include this informaton in the a-priori probability, and as a result of that the Doomsday Paradox is canceled. Now I come to the measure of observer moment : It has been said on this list, to justify we are living in this reality and not in an Harry Potter like world that somehow our reality is simpler, has higher measure than Whitte rabbit universe. But if I correlate this assumption with the DA, I also should assume that it is more probable to be in a universe with billions of billions of observer instead of this one. How are these two cases different ? Olum also stumbles on this point in his article. I also agree with Hall's earlier reply that (artificially) increasing the number of universes will lead to a decrease in intrinsic measure. One way to see this is as follows (this argument was also given by Hall a few years ago, if I remember correctly): According to the Self Sampling Asumption you have to include an ''anthropic'' factor in the measure. The more observers there are the more likely the universe is, but you do have to multiply the number of observers by the intrinsic measure. For any given universe U you can consider an universe U(n) that runs U n times, So, the anthropic factor of U(n) is n times that of U. This means that the intrinsic measure of U(n) should go to zero faster than 1/n, or else you wouldn't be able to normalize probabilities for observers. U(n) contains Log(n)/Log(2) bits more than U (you need to specify the number n). So, assuming that the intrinsic measure only depends on program size, it should decay faster than 2^(-program length). Saibal - Defeat Spammers by launching DDoS attacks on Spam-Websites: http://www.hillscapital.com/antispam/
OMs are events
I agree with the notion of OMs as events in some suitably chosen space. Observers are defined by the programs that generate them. If we identify universes with programs then observers are just embedded universes. An observer moment is just a qualia experienced by the observer, which is just an event in the observer's universe. I don't think that Hal's idea of identifying brain patterns with OMs will be successful. The brain is just the hardware that runs a program (the observer). If I run a simulation of our solar system on a computer, then the relevant events are e.g. that Jupiter is in such and such a position. This is associated with the state of the transistors of the computer running the program. But that same pattern could arise in a completely different calculation. You would have to extract exactly what program is running on the machine to be able to define OMs like that. To do that you need to feed the program with different kinds of input and study the output, otherwise you'll fall prey to the famous ''clock paradox'' (you can map the time evolution of a clock to that of any object, including brains). Saibal - Original Message - From: Aditya Varun Chadha [EMAIL PROTECTED] To: Lee Corbin [EMAIL PROTECTED]; everything-list@eskimo.com Sent: Sunday, July 31, 2005 08:46 AM Subject: Re: What We Can Know About the World [RS] On 7/31/05, Russell Standish [EMAIL PROTECTED] wrote: On Sat, Jul 30, 2005 at 12:25:48PM -0700, Lee Corbin wrote: This is not to say that progress is impossible. Consider an idea like Aditya has: what is the real difference between an event and an observer-moment? In trying to answer that question, many of us may learn something (at least for our own purposes). Err, an event is a particular set of coordinates (t,x,y,z) in 4D spacetime. This is how it is used in GR, anyway. An observer moment is a set of constraints, or equivalently information known about the world (obviously at a moment of time). It corresponds the the state vector \psi of quantum mechanics. Perhaps you have different definitions of these terms, but it seems like chalk and cheese to me. Lets not constrain an event to mean something only in 4-space. Take any N-Space and you can define it in terms of a set of N-dim. events. Ofcourse I agree with your definition, am just making it scale over dimensions. Now consider an observer moment to be exactly what you are defining it to be: information KNOWN about the world at a moment of time. The coming to know of any information corresponds to an event. Thus an observer moment is well-defined if and only if event is defined. In other words, an Observer-Moment exists iff it's corresponding coming to know event exists for some observer. In terms of light cones, OMs are the Events at and after the crossing over of light cones. I think the distinction is not a qualitative one between the two, only those events which interfere with the set of events observable by us (who are also just sets of events) correspond to observer-moments in our universe. So the set of OMs is simply a subset of the set of all events. refer to my previous mail about the multiverse as a partition with equivalence classes which are maximal sets of connected observer moments, in other words, maximal sets of mutually interfering events. visualize this as connected components of a graph. Defining entities in more than one different sets of words does not rule out their qualitative identity. Every Observer-Moment is an event. Every event is an Observer-Moment in some universe. -- Aditya Varun Chadha adichad AT gmail.com http://www.adichad.com
Re: subjective reality
Godfrey Kurtz wrote More specifically: I believe QM puts a big kabosh into any non-quantum mechanistic view of the physical world. If you don't get that, than maybe you don't get a lot of other things, Bruno. Sorry if this sounds contemptuous. It is meant to be. There aren't many people with a better understanding of QFT than 't Hooft. http://arxiv.org/abs/quant-ph/0409021 http://arxiv.org/abs/gr-qc/9903084 http://arxiv.org/abs/quant-ph/0212095 http://arxiv.org/abs/hep-th/0105105 http://arxiv.org/abs/hep-th/0104219 http://arxiv.org/abs/hep-th/0104080 Saibal
Re: subjective reality
Hi Godfrey, 't Hooft's work is motivated by problems one encounters in Planck scale physics. 't Hooft has argued that the no go theorems precluding deterministic models come with some ''small print''. Physicists working on ''conventional ways'' to unite gravity with QM are forced to make such bold assumptions that one should now also question this ''small print''. As you wrote, 't Hooft has only looked at some limited type of models. It seems to me that much more is possible. I have never tried to do any serious work in this area myself (I'm too busy with other things). I would say that anything goes as long as you can explain the macroscopic world. One could imagine that a stochastic treatment of some deterministic theory could yield the standard model, but now with the status of the quantum fields as fictitional ghosts. If photons and electrons etc. don't really exists, then you can say that this is consistent with ''no local hidden variables''. Saibal Hi Saibal, You are correct that Gerard 't Hooft is one of the world exponents in QFTh. But Quantum Field Theory is but one small piece of QM and one in which non-local effects do not play a direct role (as of yet). Understandably 't Hooft's forays into Quantum Mechanics have not, however, been very insightful as he himself confesses (you can check his humorous slides in the Kavli Institute symposium of last year on the Future of Physics). So far he has supplied mostly some interesting simple CA models from which one can indeed extract something akin to superpositions but that in no way bypasses the basic facts of entanglement and non-local correlations. He may very well be the very last hold out for a deterministic (an thus classically mechanistic) point-of-view but I would not count him out just yet. If any one around has the brain to deal with this its him! That much I will grant you... (Now I have met 't Hooft! 't Hooft was a neighbor of mine and I tell you: Bruno is no 't Hooft! ;- ) Best regards Godfrey Kurtz (New Brunswick, NJ) -Original Message- From: Saibal Mitra [EMAIL PROTECTED] To: [EMAIL PROTECTED]; [EMAIL PROTECTED] Cc: everything-list@eskimo.com Sent: Fri, 12 Aug 2005 21:11:30 +0200 Subject: Re: subjective reality Godfrey Kurtz wrote More specifically: I believe QM puts a big kabosh into any non-quantum mechanistic view of the physical world. If you don't get that, than maybe you don't get a lot of other things, Bruno. Sorry if this sounds contemptuous. It is meant to be. There aren't many people with a better understanding of QFT than 't Hooft. http://arxiv.org/abs/quant-ph/0409021 http://arxiv.org/abs/gr-qc/9903084 http://arxiv.org/abs/quant-ph/0212095 http://arxiv.org/abs/hep-th/0105105 http://arxiv.org/abs/hep-th/0104219 http://arxiv.org/abs/hep-th/0104080 Saibal Check Out the new free AIM(R) Mail -- 2 GB of storage and industry-leading spam and email virus protection.
Re: subjective reality
Hi Godfrey, As you wrote in reply to others, local deterministic models seem to be ruled out. The class of all formally describable models is much larger than that of only the local deterministic models. So, although 't Hooft may be proved wrong (if loopholes like pre-determinism don't save him), non-local models can reproduce QM. Saibal - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED]; [EMAIL PROTECTED] Cc: everything-list@eskimo.com Sent: Sunday, August 14, 2005 06:07 PM Subject: Re: subjective reality Hi Saibal, Yes, trans-Plankian physics is likely to be quite different from our cis-plankian one. However I think the main reason 't Hooft claims the no-go theorems of quantum physics are in small print is because his reading glasses are no longer current :-), I am afraid. His arguments for the prevalence of simple deterministic models at this scaled have varied over the years (as his little examples) and some of these are quite clever, I'll agree. However, as you very well point out, any transplankian theory worth looking into has to reproduce a recognizable picture of the cisplankian world we know and that means: quantum mechanics (non-locality and all) in some discernible limit (and General Relativity too in some other limit) and all indications is that this cannot be done from deterministic models alone. 't Hooft has been working around this for the last 10 years or so and he doesn't have much to show for it. Considering that it took him less than 2 years to come up with a renormalization prescription for non-abelian gauge theories in his youth I suspect god's dice are loaded against him this time. However he is always fascinating to read and hear. I saw him at Harvard this winter for the Colemanfest and he had the most fabulous animations... Godfrey Kurtz (New Brunswick, NJ) -Original Message- From: Saibal Mitra [EMAIL PROTECTED] To: [EMAIL PROTECTED]; [EMAIL PROTECTED] Cc: everything-list@eskimo.com Sent: Sat, 13 Aug 2005 01:34:19 +0200 Subject: Re: subjective reality Hi Godfrey, 't Hooft's work is motivated by problems one encounters in Planck scale physics. 't Hooft has argued that the no go theorems precluding deterministic models come with some ''small print''. Physicists working on ''conventional ways'' to unite gravity with QM are forced to make such bold assumptions that one should now also question this ''small print''. As you wrote, 't Hooft has only looked at some limited type of models. It seems to me that much more is possible. I have never tried to do any serious work in this area myself (I'm too busy with other things). I would say that anything goes as long as you can explain the macroscopic world. One could imagine that a stochastic treatment of some deterministic theory could yield the standard model, but now with the status of the quantum fields as fictitional ghosts. If photons and electrons etc. don't really exists, then you can say that this is consistent with ''no local hidden variables''. Saibal Hi Saibal, You are correct that Gerard 't Hooft is one of the world exponents in QFTh. But Quantum Field Theory is but one small piece of QM and one in which non-local effects do not play a direct role (as of yet). Understandably 't Hooft's forays into Quantum Mechanics have not, however, been very insightful as he himself confesses (you can check his humorous slides in the Kavli Institute symposium of last year on the Future of Physics). So far he has supplied mostly some interesting simple CA models from which one can indeed extract something akin to superpositions but that in no way bypasses the basic facts of entanglement and non-local correlations. He may very well be the very last hold out for a deterministic (an thus classically mechanistic) point-of-view but I would not count him out just yet. If any one around has the brain to deal with this its him! That much I will grant you... (Now I have met 't Hooft! 't Hooft was a neighbor of mine and I tell you: Bruno is no 't Hooft! ;- ) Best regards Godfrey Kurtz (New Brunswick, NJ) -Original Message- From: Saibal Mitra [EMAIL PROTECTED] To: [EMAIL PROTECTED]; [EMAIL PROTECTED] Cc: everything-list@eskimo.com Sent: Fri, 12 Aug 2005 21:11:30 +0200 Subject: Re: subjective reality Godfrey Kurtz wrote More specifically: I believe QM puts a big kabosh into any non-quantum mechanistic view of the physical world. If you don't get that, than maybe you don't get a lot of other things, Bruno. Sorry if this sounds contemptuous. It is meant to be. There aren't many people with a better understanding of QFT than 't Hooft. http://arxiv.org/abs/quant-ph/0409021 http://arxiv.org/abs/gr-qc
How did it all begin?
http://arxiv.org/abs/astro-ph/0508429 Tegmark's essay was not well received (perhaps Godfrey didn't like it? :-) ) How did it all begin? Authors: Max Tegmark Comments: 6 pages, 6 figs, essay for 2005 Young Scholars Competition in honor of Charles Townes; received Dishonorable Mention How did it all begin? Although this question has undoubtedly lingered for as long as humans have walked the Earth, the answer still eludes us. Yet since my grandparents were born, scientists have been able to refine this question to a degree I find truly remarkable. In this brief essay, I describe some of my own past and ongoing work on this topic, centering on cosmological inflation. I focus on (1) observationally testing whether this picture is correct and (2) working out implications for the nature of physical reality (e.g., the global structure of spacetime, dark energy and our cosmic future, parallel universes and fundamental versus environmental physical laws). (2) clearly requires (1) to determine whether to believe the conclusions. I argue that (1) also requires (2), since it affects the probability calculations for inflation's observational predictions.
Re: How did it all begin?
Hi Norman, I have no idea why it received a dishonorable mention. It could be because some physicists/cosmologists don't like anthropic reasoning. - Original Message - From: Norman Samish [EMAIL PROTECTED] To: Saibal Mitra [EMAIL PROTECTED] Cc: everything-list@eskimo.com Sent: Wednesday, August 31, 2005 12:57 AM Subject: Re: How did it all begin? This is a teaser. Why did Tegmark's paper receive Dishonorable Mention? Who is Godfrey? - Original Message - From: Saibal Mitra [EMAIL PROTECTED] To: everything everything-list@eskimo.com Sent: Tuesday, August 30, 2005 6:14 AM Subject: How did it all begin? http://arxiv.org/abs/astro-ph/0508429 Tegmark's essay was not well received (perhaps Godfrey didn't like it? :-) ) How did it all begin? Authors: Max Tegmark Comments: 6 pages, 6 figs, essay for 2005 Young Scholars Competition in honor of Charles Townes; received Dishonorable Mention How did it all begin? Although this question has undoubtedly lingered for as long as humans have walked the Earth, the answer still eludes us. Yet since my grandparents were born, scientists have been able to refine this question to a degree I find truly remarkable. In this brief essay, I describe some of my own past and ongoing work on this topic, centering on cosmological inflation. I focus on (1) observationally testing whether this picture is correct and (2) working out implications for the nature of physical reality (e.g., the global structure of spacetime, dark energy and our cosmic future, parallel universes and fundamental versus environmental physical laws). (2) clearly requires (1) to determine whether to believe the conclusions. I argue that (1) also requires (2), since it affects the probability calculations for inflation's observational predictions.
Re: subjective reality
Hi Norman, I agree that you can assume that one multiverse exists and that that implies that everything describable exists. But If physical existence is not the same as mathematical existence then there is nothing we can do to verify this. So, this like postulating that a powerless God exists. Saibal - Original Message - From: Norman Samish [EMAIL PROTECTED] To: everything-list@eskimo.com Sent: Saturday, September 03, 2005 09:33 PM Subject: Re: subjective reality Hi Saibal, While my simple mind believes that mathematical existence = physical existence, I do not assume that we owe our existence to the mere existence of the algorithm, not a machine that executes it. To me, the reason that mathematical existence means physical existence is that in infinite space and time, everything that can exist must exist. If it's describable mathematically, then it can exist, somewhere in the multiverse - therefore it must exist. Tegmark claims, for example, that in his Level I multiverse, there is an identical copy of (me) about 10^10^29 meters away. (arXiv:astro-ph/0302131 v1 7 Feb 2003) Norman ~~ - Original Message - From: Saibal Mitra [EMAIL PROTECTED] To: [EMAIL PROTECTED]; [EMAIL PROTECTED] Cc: everything-list@eskimo.com Sent: Saturday, September 03, 2005 7:10 AM Subject: Re: subjective reality Hi Godfrey, It is not clear to me why one would impose constraints such as locality etc. here. Ignoring the exact details of what Bruno (and others) are doing, it all all boils down to this: Does there exists an algorithm that when run on some computer would generate an observer who would subjectively perceive his virtual world to be similar to the world we live in (which is well described by the standard model and GR). The quantum fields are represented in some way by the states of the transistors of the computer. The way the computer evolves from one state to the next, of course, doesn't violate ''our laws of physics''. It may be the case that the way the transistors are manipulated by the computer when interpreted in terms of the quantum fields in the ''virtual world'' would violate the laws of physics of that world. But this is irrelevant, because the observer cannot violate the laws of physics in his world. Also, if you believe that ''mathematical existence= physical existence'', then you assume that we owe our existence to the mere existence of the algorithm, not a machine that executes it. Saibal - Defeat Spammers by launching DDoS attacks on Spam-Websites: http://www.hillscapital.com/antispam/
Re: What Computationalism is and what it is *not*
Hi Norman, A TM in our universe can simulate you living in a virtual universe. If your universe is described by the same laws of physics as ours, then most physicists believe that the TM would have to work in a nonlocal way from your perspective. Is this a problem? I don't think so, because the TM doesn't exist in your universe, it exists in our universe and it doesn't violate locality here. The TM generates your universe in which locality cannot be violated. So, I don't see the problem. Saibal - Original Message - From: Norman Samish [EMAIL PROTECTED] To: everything-list@eskimo.com Sent: Monday, September 05, 2005 08:44 PM Subject: Re: What Computationalism is and what it is *not* Hal Finney, You say, . . . the Church Thesis, which I would paraphrase as saying that there are no physical processes more computationally powerful than a Turing machine, or in other words that the universe could in principle be simulated on a TM. I wouldn't be surprised if most people who believe that minds can be simulated on TMs also believe that everything can be simulated on a TM. I'm out of my depth here, but this doesn't make sense to me. My understanding is that the Turing Machine is a hypothetical device. If one could be built that operated at faster-than-light or infinite speed, maybe it could, in principle, simulate the universe. However, this isn't possible. Does this mean that the Church Thesis, hence computationalism, is, in reality, false? Norman Samish - Defeat Spammers by launching DDoS attacks on Spam-Websites: http://www.hillscapital.com/antispam/
Re: What Computationalism is and what it is *not*
Hi Norman, Only when you demand that the computations be done in real time there is a problem. My point is that this problem is not relevant. Any TM that you can build will have limitations because of the laws of physics. Suppose that simulating the time evolution of 1 isolated cubic meter of space containing matter for 1 second takes at least 1 billion years for a computer the size of our solar system. Then I would say that I can simulate a few seconds of your consciousness because you only experience simulated time. You may say that because your simulated brain can't interact with the rest of the (real) universe this doesn't qualify as a ''bona fide'' simulation. Saibal - Original Message - From: Norman Samish [EMAIL PROTECTED] To: Saibal Mitra [EMAIL PROTECTED] Sent: Tuesday, September 06, 2005 05:48 AM Subject: Re: What Computationalism is and what it is *not* Hi Saibal, Thanks for your reply. But semantics once again rears its ugly head! Norman - Original Message - From: Saibal Mitra [EMAIL PROTECTED] To: Norman Samish [EMAIL PROTECTED]; everything-list@eskimo.com Sent: Monday, September 05, 2005 3:08 PM Subject: Re: What Computationalism is and what it is *not* Hi Norman, (SM) A TM in our universe can simulate you living in a virtual universe. If your universe is described by the same laws of physics as ours, then most physicists believe that the TM would have to work in a nonlocal way from your perspective. (NS) What do you mean by nonlocal? Wikipedia says Nonlocality in quantum mechanics, refers to the property of entangled quantum states in which both the entangled states collapse simultaneously upon measurement of one of their entangled components, regardless of the spatial separation of the two states. I don't understand what that has to do with the TM. (SM) Is this a problem? I don't think so, because the TM doesn't exist in your universe, it exists in our universe and it doesn't violate locality here. The TM generates your universe in which locality cannot be violated. So, I don't see the problem. (NS) Are you saying that the universe that the Turing Machine simulates is different from the one that I'm in, and in this simulated universe the speed limits on the speed of the TM don't apply? No - that can't be it. I'm sorry - I guess I don't know what you mean. The problem that I posed is that I don't understand how a finite-speed Turing Machine can simulate a universe, contrary to the assertions of the Church Thesis. Whether or not I'm in the universe to be simulated seem irrelevant. The computation in such a simulation is so immense that it must take a faster-than-light TM, which is not possible. Therefore, it seems to me, computationalism must be false. - Defeat Spammers by launching DDoS attacks on Spam-Websites: http://www.hillscapital.com/antispam/
Re: Neutrino shield idea
This means that beta decay proves your model wrong. - Original Message - From: John Ross [EMAIL PROTECTED] To: 'Stephen Paul King' [EMAIL PROTECTED]; everything-list@eskimo.com Sent: Saturday, October 08, 2005 12:35 AM Subject: RE: Neutrino shield idea Thanks for the paper relating to detection of low energy neutrinos. However, according to my model, neutrinos are very, very high energy photons (off everybody's chart, except mine). Therefore, if my model is correct, then low energy neutrinos would merely be the photons we are familiar with and would be very easy to detect. -Original Message- From: Stephen Paul King [mailto:[EMAIL PROTECTED] Sent: Friday, October 07, 2005 12:54 PM To: everything-list@eskimo.com Subject: Neutrino shield idea Howdy! I friend of mine has worked on a related idea that might help this inverstigation. Please see: http://davidwoolsey.com/physics/ideas/neutrinoscope/index.html Kindest regards, Stephen - Original Message - From: John Ross [EMAIL PROTECTED] To: [EMAIL PROTECTED] Cc: everything-list@eskimo.com Sent: Friday, October 07, 2005 11:57 AM Subject: RE: ROSS MODEL OF THE UNIVERSE - The Simplest Yet Theory of Everything Yes. But building a neutrino shield would be difficult.
Re: Neutrino shield idea
There are a lot of experiments that have detected neutrinos and verified their properties (which are completely different from photons). - Original Message - From: John Ross [EMAIL PROTECTED] To: 'Saibal Mitra' [EMAIL PROTECTED]; everything-list@eskimo.com Sent: Monday, October 10, 2005 10:49 PM Subject: RE: Neutrino shield idea I think the beta decay model is wrong where it predicts neutrinos are basically different from photons. I understand neutrinos travel at the speed of light. Only photons travel at the speed of light. -Original Message- From: Saibal Mitra [mailto:[EMAIL PROTECTED] Sent: Friday, October 07, 2005 4:30 PM To: John Ross; everything-list@eskimo.com Subject: Re: Neutrino shield idea This means that beta decay proves your model wrong. - Original Message - From: John Ross [EMAIL PROTECTED] To: 'Stephen Paul King' [EMAIL PROTECTED]; everything-list@eskimo.com Sent: Saturday, October 08, 2005 12:35 AM Subject: RE: Neutrino shield idea Thanks for the paper relating to detection of low energy neutrinos. However, according to my model, neutrinos are very, very high energy photons (off everybody's chart, except mine). Therefore, if my model is correct, then low energy neutrinos would merely be the photons we are familiar with and would be very easy to detect. -Original Message- From: Stephen Paul King [mailto:[EMAIL PROTECTED] Sent: Friday, October 07, 2005 12:54 PM To: everything-list@eskimo.com Subject: Neutrino shield idea Howdy! I friend of mine has worked on a related idea that might help this inverstigation. Please see: http://davidwoolsey.com/physics/ideas/neutrinoscope/index.html Kindest regards, Stephen - Original Message - From: John Ross [EMAIL PROTECTED] To: [EMAIL PROTECTED] Cc: everything-list@eskimo.com Sent: Friday, October 07, 2005 11:57 AM Subject: RE: ROSS MODEL OF THE UNIVERSE - The Simplest Yet Theory of Everything Yes. But building a neutrino shield would be difficult.
Re: Neutrino shield idea
I'm sure you saw something else :-) - Original Message - From: John Ross [EMAIL PROTECTED] To: 'Russell Standish' [EMAIL PROTECTED] Cc: 'Hal Ruhl' [EMAIL PROTECTED]; everything-list@eskimo.com Sent: Tuesday, October 11, 2005 01:40 AM Subject: RE: Neutrino shield idea I say a neutrino does not have a rest mass. It is a photon, like a very high energy gamma ray photon. I have seen photos of a neutrino collision in a neutrino trap. From the look of all the resulting ionization tracks, it must have had a lot more energy than 40 ev. I say the energy of neutrinos is in the range of 300 mev! -Original Message- From: Russell Standish [mailto:[EMAIL PROTECTED] Sent: Monday, October 10, 2005 3:00 PM To: John Ross Cc: 'Hal Ruhl'; everything-list@eskimo.com Subject: Re: Neutrino shield idea According to special relativity, anything with a positive rest mass travels slower than the speed of light. Neutrinos have been measured with a positive rest mass, of around 40ev for the electron neutrino IIRC, and higher values for the muon and tauon neutrinos. I have never heard of either tardyon or luxon before either, but have heard of tachyon, or faster than light particle. Clearly tardyon is therefore slower than light, and luxon is at light speed. Luxons therefore have zero rest mass, and tachyons have imaginary (ie proportional to sqrt(-1)) rest mass. Cheers On Mon, Oct 10, 2005 at 03:06:55PM -0700, John Ross wrote: Where is the proof that a neutrino is not a photon. I believe people are only guessing that a neutrino is a tardyon, whatever in the hell a tardyon is. Tardyons are not in my dictionary. -Original Message- From: Hal Ruhl [mailto:[EMAIL PROTECTED] Sent: Monday, October 10, 2005 2:50 PM To: everything-list@eskimo.com Subject: RE: Neutrino shield idea As I understand it a photon is a luxon as is a gluon and a neutrino is a tardyon. Hal Ruhl At 04:49 PM 10/10/2005, you wrote: I think the beta decay model is wrong where it predicts neutrinos are basically different from photons. I understand neutrinos travel at the speed of light. Only photons travel at the speed of light. -Original Message- From: Saibal Mitra [mailto:[EMAIL PROTECTED] Sent: Friday, October 07, 2005 4:30 PM To: John Ross; everything-list@eskimo.com Subject: Re: Neutrino shield idea This means that beta decay proves your model wrong. - Original Message - From: John Ross [EMAIL PROTECTED] To: 'Stephen Paul King' [EMAIL PROTECTED]; everything-list@eskimo.com Sent: Saturday, October 08, 2005 12:35 AM Subject: RE: Neutrino shield idea Thanks for the paper relating to detection of low energy neutrinos. However, according to my model, neutrinos are very, very high energy photons (off everybody's chart, except mine). Therefore, if my model is correct, then low energy neutrinos would merely be the photons we are familiar with and would be very easy to detect. -Original Message- From: Stephen Paul King [mailto:[EMAIL PROTECTED] Sent: Friday, October 07, 2005 12:54 PM To: everything-list@eskimo.com Subject: Neutrino shield idea Howdy! I friend of mine has worked on a related idea that might help this inverstigation. Please see: http://davidwoolsey.com/physics/ideas/neutrinoscope/index.html Kindest regards, Stephen - Original Message - From: John Ross [EMAIL PROTECTED] To: [EMAIL PROTECTED] Cc: everything-list@eskimo.com Sent: Friday, October 07, 2005 11:57 AM Subject: RE: ROSS MODEL OF THE UNIVERSE - The Simplest Yet Theory of Everything Yes. But building a neutrino shield would be difficult. -- *PS: A number of people ask me about the attachment to my email, which is of type application/pgp-signature. Don't worry, it is not a virus. It is an electronic signature, that may be used to verify this email came from me if you have PGP or GPG installed. Otherwise, you may safely ignore this attachment. A/Prof Russell Standish Phone 8308 3119 (mobile) Mathematics0425 253119 () UNSW SYDNEY 2052 [EMAIL PROTECTED] Australia http://parallel.hpc.unsw.edu.au/rks International prefix +612, Interstate prefix 02
Re: Neutrino shield idea
Faster than light effects lead to violations of causality. There are very stringent experimental constraints against such effects. - Original Message - From: John Ross [EMAIL PROTECTED] To: 'Russell Standish' [EMAIL PROTECTED] Cc: 'Stephen Paul King' [EMAIL PROTECTED]; everything-list@eskimo.com Sent: Tuesday, October 11, 2005 01:43 AM Subject: RE: Neutrino shield idea I say any massless particle that has a charge supporting a Coulomb force must travel at the speed of light or faster because the Coulomb force travels at the speed of light and a charged massless particle will be repelled by its own Coulomb force. -Original Message- From: Russell Standish [mailto:[EMAIL PROTECTED] Sent: Monday, October 10, 2005 3:04 PM To: John Ross Cc: 'Stephen Paul King'; everything-list@eskimo.com Subject: Re: Neutrino shield idea On Mon, Oct 10, 2005 at 09:11:04AM -0700, John Ross wrote: * Only photons travel at the speed of light. (Except my tronnies that usually go faster than the speed of light.) Who says? Any massless particle will travel at the speed of light. -- *PS: A number of people ask me about the attachment to my email, which is of type application/pgp-signature. Don't worry, it is not a virus. It is an electronic signature, that may be used to verify this email came from me if you have PGP or GPG installed. Otherwise, you may safely ignore this attachment. A/Prof Russell Standish Phone 8308 3119 (mobile) Mathematics0425 253119 () UNSW SYDNEY 2052 [EMAIL PROTECTED] Australia http://parallel.hpc.unsw.edu.au/rks International prefix +612, Interstate prefix 02
Tegmark's prediction of neutrino masses
Since we are discussing neutrinos, I thought it is fun to mention antropic constraints on neutrino masses derived by Tegmark, see here: http://arxiv.org/abs/astro-ph/0304536 Anthropic predictions for neutrino masses Authors: Max Tegmark (MIT), Alexander Vilenkin (Tufts), Levon Pogosian (Tufts) Categories: astro-ph Comments: Revised to match accepted PRD version. Added references, discussion of very heavy neutrinos, analytic growth factor fit. 9 pages, 4 figs. Color figs and links at this http URL Journal-ref: Phys.Rev. D71 (2005) 103523 It is argued that small values of the neutrino masses may be due to anthropic selection effects. If this is the case, then the combined mass of the three neutrino species is expected to be ~1eV, neutrinos causing a non-negligible suppression of galaxy formation. http://arxiv.org/abs/astro-ph/0404497 Anthropic predictions for vacuum energy and neutrino masses Authors: Levon Pogosian, Alexander Vilenkin, Max Tegmark Categories: astro-ph gr-qc hep-th Comments: 9 pages, 4 figures Journal-ref: JCAP 0407 (2004) 005 It is argued that the observed vacuum energy density and the small values of the neutrino masses could be due to anthropic selection effects. Until now, these two quantities have been treated separately from each other and, in particular, anthropic predictions for the vacuum energy were made under the assumption of zero neutrino masses. Here we consider two cases. In the first, we calculate predictions for the vacuum energy for a fixed (generally non-zero) value of the neutrino mass. In the second we allow both quantities to vary from one part of the universe to another. We find that the anthropic predictions for the vacuum energy density are in a better agreement with observations when one allows for non-zero neutrino masses. We also find that the individual distributions for the vacuum energy and the neutrino masses are reasonably robust and do not change drastically when one adds the other variable. - Defeat Spammers by launching DDoS attacks on Spam-Websites: http://www.hillscapital.com/antispam/
Re: Quantum theory of measurement
Hal gives the correct explanation of what's going on. In general, all you have to do to analyze the problem is to consider all contributions to a particular state and add up the amplitudes. The absolute value squared of the amplitude gives the probability, which may or may not contain an interference term. A simple minded formal description can be given as follows: If you pass a photon through two slits then close to the screen its state would be of the form: Integral over z of [1 + Exp(i delta(z))] |s,z Here z denotes the postion on the screen, s is just a label for the photon and Exp(i delta(z)) is the phase shift between the two paths which gives rise to the interference term. Delta(z) will be zero exactly inbetween the two slits and will be nonzero elsewhere. The probability of having the photon at z is obtained (up to normalization) by taking the absolute value squared of the prefactor of |s,z, which is 2 + 2 cos(delta(z)). Let's do the same for the two entagled photons. The entangled photon pair can be denoted as: |p_x,s_y + |p_y,s_x here x and y denote the polarization states. If you pass s through the two slits then the state becomes: [1 + Exp(i delta(z))] |p_x,s_y,z + [1 + Exp(i delta(z))] ||p_y,s_x,z This has to be integrated over z, but let's focus only at the contribution at some fixed position z. The prefactors of both state vectors |p_x,s_y,z and |p_y,s_x,z are of the same form as in the single photon case and thus you get an interference term Cos(delta(z) as above. If you put the quarter wave plate in then instead of [1 + Exp(i delta(z))] |p_x,s_y,z you get: |p_x,s_r,z + Exp(i delta(z)) |p_x,s_l,z And the complete state vector becomes: |p_x,s_r,z + Exp(i delta(z)) |p_x,s_l,z+ |p_y,s_l,z + Exp(i delta(z)) |p_y,s_r,z All the four state vectors are orthogonal. The probability that you detect the photon s at z is just the sum of the absolute value squared of the four terms, which is constant and doesn't contain an interference term. Now let's pass photon p through the polarizer (45 degrees w.r.t. x). This amounts to measuring the polarization state of photon p in the basis |p_x + p_y and |p_x - p_y. If you don't discard one of these two states and keep them both then, as Hal rightly points out, nothing changes. If you substitute: |p_x = |a + |b; |p_y = |a - |b in the state vector above you get: |a,s_r,z + Exp(i delta(z)) |a,s_l,z+ |a,s_l,z + Exp(i delta(z)) |a,s_r,z+ |b,s_r,z + Exp(i delta(z)) |b,s_l,z+ - |b,s_l,z - Exp(i delta(z)) |b,s_r,z = (collecting the prefactors of like state vectors) = [1 + Exp(i delta(z))]|a,s_r,z + [1 + Exp(i delta(z))]|a,s_l,z + [1 - Exp(i delta(z))]|b,s_r,z - [1 - Exp(i delta(z))] |b,s_l,z The absolute value squared of the terms with the p photons in the |a state contains the term 2 Cos (delta(z)), but for the b terms this is - 2 Cos(delta(z). If you don't observe the polarization of the p photon, the interference terms would thus cancel. This is obvious since all we have done is to write down the same state in a different basis. But if you do observe the polarization of the p photon, then can measure the probability of detecting s at position z and p in polarization state |a then you have to add up the absolute value squared of |a,s_r,z and |a,s_l,z. Then you do get the Cos(delta(z) interference term. - Original Message - From: Hal Finney [EMAIL PROTECTED] To: [EMAIL PROTECTED]; everything-list@eskimo.com Sent: Wednesday, October 12, 2005 08:16 PM Subject: Re: Quantum theory of measurement Ben Goertzel writes about: http://grad.physics.sunysb.edu/~amarch/ The questions I have regard the replacement of the Coincidence Counter (from here on: CC) in the above experiment with a more complicated apparatus. What if we replace the CC with one of the following: 1) a carefully sealed, exquisitely well insulated box with a printer inside it. The printer is hooked up so that it prints, on paper, an exact record of everything that comes into the CC. Then, to erase the printed record, the whole box is melted, or annihilated using nuclear explosives, or whatever. The CC is not what is erased. Rather, the so-called erasure happens to the photons while they are flying through the apparatus. Nothing in the experiment proposes erasing data in the CC. So I don't really see what you are getting at. What will the outcome be in these experiments? It won't make any difference, because the CC is not used in the way you imagine. It doesn't have to produce a record and it doesn't have to erase any records. Let me tell you what really happens in the experiment above. It is actually not so mystical as people try to make it sound. We start off with the s photon going through a 2 slit experiment and getting interference. That is standard. Now we put two different polarization rotations in front of the two slits and interference goes away. The web page author professes
Re: Quantum theory of measurement
Well, as you can see here: http://cabtep5.cnea.gov.ar/particulas/daniel/curri/curreng.html He isn't very experienced yet. I know of some experienced professors of have made worse mistakes :) So, what goes wrong? Well, you don't get an interference pattern at one end even if you don't detect the photon at the other end. To see this, just write down the two particle state and add the phase shifts. If the detectors on the other sides are off, then the two contributions corresponding to the photon being detected at some position z consist of two orthogonal terms; one term correpsonds to the other photon in pipe 1 and the other for that photon in pipe 2 Suppose that you add a plate to detect the photon on that side as well. Then the probability that the photon at one end is detected at position z1 and the other is detected at z2 does contain an interference term of the form: Cos[delta1(z1) + delta2(z2)] If you don't detect where photon 2 is absorbed you have to integrate over z2 and the interference term vanishes. To see an interference term you must keep z2 fixed. This means that you must consider only those photons for which the entangled partners were detected at at some fixed z2. But this means that this value must be communicated by the observer there. - Original Message - From: Hal Finney [EMAIL PROTECTED] To: everything-list@eskimo.com Sent: Thursday, October 13, 2005 03:59 AM Subject: RE: Quantum theory of measurement Now that you are experts on this, try your hand on this FTL signalling device, http://arxiv.org/abs/quant-ph?0204108. The author, Daniel Badagnani, is apparently a genuine physicist, http://cabtep5.cnea.gov.ar/particulas/daniel/pag-db.html. Hal Finney
Re: Quantum Immortality and Information Flow
- Original Message - From: Jonathan Colvin [EMAIL PROTECTED] To: everything-list@eskimo.com Sent: Sunday, November 27, 2005 05:49 AM Subject: RE: Quantum Immortality and Information Flow Saibal wrote: The answer must be a) because (and here I disagree with Jesse), all that exists is an ensemble of isolated observer moments. The future, the past, alternative histories, etc. they all exist in a symmetrical way. It don't see how some states can be more ''real'' than other states. Of course, the universe we experience seems to be real to us while alternative universes, or past or future states of this universe are not being experienced by us. So, you must think of yourself at any time as being randomly sampled from the set of all possible observer moments. delurk I'm not sure how this works. Suppose I consider my state now at time N as a random sample of all observer moments. Now, after having typed this sentence, I consider my state at time N + 4 seconds. Is this also a random sample on all observer moments? I can do the same at now N+10, and so-on. It seems very unlikely that 3 random samples would coincide so closely. So in what sense are these states randomly sampled? It's a bit like symmetry breaking. You have an ensemble of all possible observer moment, but each observer moment can only experience its own state. So, the OM samples itself. There exists an observer moment representing you at N seconds, at N + 4 seconds and at all possible other states. They all ''just exist'' in the plenitude, as Stathis wrote. The OM representing you at N + 4 has the memory of being the OM at N. Subjectively the OMs experience time evolution, even though the plenitude itself doesn't have a time evolution at the fundamental level. Although it is a bit strange to think about time evolution in this way, it is necessary to resolve paradoxes you get when contemplating doubling and suicide experiments. It is precisely in these cases that our naive notion of time evolution breaks down. Saibal
Re: Quantum Immortality and Information Flow
Correction, I seem to have misunderstood Statis' set up. If you really create a new world and then create and kill the person there then the probability of survival is 1. This is different from quantum mechanical branch splitting. To see this, consider first what would have happened had the person not been killed. Then his measure would have doubled. But because he is killed in one of the two copies of Earth, his measure stays the same. In a quantum suicide experiment his measure would be reduced by a factor two. - Original Message - From: Saibal Mitra [EMAIL PROTECTED] To: Stathis Papaioannou [EMAIL PROTECTED]; [EMAIL PROTECTED]; Jesse Mazer [EMAIL PROTECTED] Cc: everything-list@eskimo.com Sent: Sunday, November 27, 2005 02:25 AM Subject: Re: Quantum Immortality and Information Flow The answer must be a) because (and here I disagree with Jesse), all that exists is an ensemble of isolated observer moments. The future, the past, alternative histories, etc. they all exist in a symmetrical way. It don't see how some states can be more ''real'' than other states. Of course, the universe we experience seems to be real to us while alternative universes, or past or future states of this universe are not being experienced by us. So, you must think of yourself at any time as being randomly sampled from the set of all possible observer moments. To get to answer b) you have to redefine your identity so that experiencing having done the experiment becomes a necessary part of your identity. But this is cheating because you wouldn't say that if ''death'' were replaced by a partial memory erasure such that the experience of having done the experiment were wiped out form your memory. - Original Message - From: Stathis Papaioannou [EMAIL PROTECTED] To: [EMAIL PROTECTED] Cc: everything-list@eskimo.com Sent: Saturday, November 26, 2005 11:51 AM Subject: Re: Quantum Immortality and Information Flow Stathis Papaioannou writes: If on the basis of a coin toss the world splits, and in one branch I am instantaneously killed while in the other I continue living, there are several possible ways this might be interpreted from the 1st person viewpoint: (a) Pr(I live) = Pr(I die) = 0.5 (b) Pr(I live) = 1, Pr(I die) = 0 (c) Pr(I live) = 0, Pr(I die) = 1 Even on this list, there are people who might say (a) above is the case rather than (b) or (c). Bruno Marchal replies: Are you sure? I was thinking of people who accept some ensemble theory such as MWI, but don't believe in QTI. I must admit, I find it difficult to understand how even a dualist might justify (a) as being correct. Would anyone care to help? Stathis _ Start something musical - 15 free ninemsn Music downloads! http://ninemsn.com.au/share/redir/adTrack.asp?mode=clickclientID=667referral=HotmailTaglineNovURL=http://www.ninemsn.com.au/startsomething
Re: Quantum Immortality and Information Flow
This doubling of the absolute measure is important. In another posting you wrote about being teleported to many places and then being annihilated everywhere except at the original place. This won't affect the probability of being alive at the original place. But in a QC experiment where you have many outcomes, all leading to death except one, the probability of experiencing that branch is very small. - Original Message - From: Stathis Papaioannou [EMAIL PROTECTED] To: [EMAIL PROTECTED]; everything-list@eskimo.com Sent: Saturday, December 03, 2005 11:38 AM Subject: Re: Quantum Immortality and Information Flow Well, I did actually intend my example to be analogous to the Tegmark QS experiment. Are you saying that if there is only one world and magically an identical, separate world comes into being this is fundamentally different to what happens in quantum branch splitting? It seems to me that in both cases the relative measure of everything in the world stays the same, even though in absolute terms there is double of everything. Stathis Papaioannou Saibal Mitra writes: Correction, I seem to have misunderstood Statis' set up. If you really create a new world and then create and kill the person there then the probability of survival is 1. This is different from quantum mechanical branch splitting. To see this, consider first what would have happened had the person not been killed. Then his measure would have doubled. But because he is killed in one of the two copies of Earth, his measure stays the same. In a quantum suicide experiment his measure would be reduced by a factor two. If on the basis of a coin toss the world splits, and in one branch I am instantaneously killed while in the other I continue living, there are several possible ways this might be interpreted from the 1st person viewpoint: (a) Pr(I live) = Pr(I die) = 0.5 (b) Pr(I live) = 1, Pr(I die) = 0 (c) Pr(I live) = 0, Pr(I die) = 1 _ Buy now @ Tradingpost.com.au http://a.ninemsn.com.au/b.aspx?URL=http%3A%2F%2Fad%2Eau%2Edoubleclick%2Enet%2Fclk%3B23850242%3B12217581%3Bw%3Fhttp%3A%2F%2Fwww%2Etradingpost%2Ecom%2Eau%2F%3Freferrer%3DnmsnHMetag_t=11482_r=emaildec05_m=EXT
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Re: Quantum Immortality and Information Flow
- Original Message - From: Johnathan Corgan [EMAIL PROTECTED] To: Stathis Papaioannou [EMAIL PROTECTED] Cc: everything-list@eskimo.com Sent: Wednesday, December 14, 2005 10:39 AM Subject: Re: Quantum Immortality and Information Flow Stathis Papaioannou wrote: In the multiverse, only other people end up in dead ends. Kind of makes you wonder what Tookie is doing right now. To us, he died as a result of lethal injection. What sort of successor observer-moments can follow a thing like that? Better question--what is the most likely type of 1st-person observer-moment that would follow experiencing lethal injection? Sure, there is an infinitesimal probability that all his constituent particles quantum-tunneled to a Pacific island paradise and right now somewhere in the multiverse he's enjoying a drink with an umbrella in it, thanking the fine State of California for his new life. More likely, but still infinitesimally small, is the probability that only the molecules of toxin in the injection syringe quantum-tunneled away and right now there are execution officials puzzling over whether to pardon him after this act-of-God miraculous reprieve from death. But seriously, when the overwhelmingly vast majority of successor moments to an instant in time are all 3rd-person dead-ends, what would would be an example of a high-expectation 1st-person successor observer-moment from the tiny sliver of physically possible (but extremely unlikely) ones left? Is there in fact always one left, no matter how unlikely? To me it seems that the notion of ''successor'' has to break down at cases where the observer can die. The Tookies that are the most similar to the Tookie who got executed are the ones who got clemency. There is no objective reason why these Tookies should be excluded as ''successors''. They miss the part of their memories about things that happened after clemency was denied. Instead of those memories they have other memories. We forget things all the time. Sometimes we remember things that didn't really happen. So, we allow for information loss anyway. My point is then that we should forget about all of the information contained in the OM and just sample from the entire set of OMs. The notion of a ''successor'' is not a fundamental notion at all. You can define it any way you like. It will not lead to any conflict with any experiments you can think of.
Re: Quantum Immortality and Information Flow
Hi Bruno, Well, even if you can derive the laws of physics as we know them (in some approximation), you still can't do an experiment to prove that quantum suicide works. It can only be proven to the experimentor himself. This means that the absolute measure cannot be ruled out experimentally. - Original Message - From: Bruno Marchal [EMAIL PROTECTED] To: Saibal Mitra [EMAIL PROTECTED] Cc: everything-list@eskimo.com Sent: Thursday, December 15, 2005 01:25 PM Subject: Re: Quantum Immortality and Information Flow Le 15-déc.-05, à 03:04, Saibal Mitra a écrit : To me it seems that the notion of ''successor'' has to break down at cases where the observer can die. The Tookies that are the most similar to the Tookie who got executed are the ones who got clemency. There is no objective reason why these Tookies should be excluded as ''successors''. They miss the part of their memories about things that happened after clemency was denied. Instead of those memories they have other memories. We forget things all the time. Sometimes we remember things that didn't really happen. So, we allow for information loss anyway. My point is then that we should forget about all of the information contained in the OM and just sample from the entire set of OMs. The notion of a ''successor'' is not a fundamental notion at all. You can define it any way you like. ? It will not lead to any conflict with any experiments you can think of. ? Counterexamples will appear if I succeed to explain more of the conversation with the lobian machines. But just with the Kripke semantics we have a base to doubt what you are saying here. Indeed, it is the relation of accessibility between OMs which determine completely the invariant laws pertaining in all OMs. For example, if the multiverse is reflexive the Bp - p is true in all OMs (that is, Bp - p is invariant for any walk in the multiverse). If the mutliverse is terminal of papaioannou-like) then Dt - ~BDt is a law. In Kripke structure the accessibility relation determined the invariant laws. later, the modal logic is given by the machine interview, and from that, we will determine the structure of the multiverse, including the observable one. Bruno http://iridia.ulb.ac.be/~marchal/
Re: Multiverse concepts in string theory
Hi Stephen,
Yes I agree. But once you have many scientists
believing in a certain paradigm, it takes radical new discoveries to overturn
it. The lack of confirmation is usually not enough.
Saibal
- Original Message -
From:
Stephen
Paul King
To: everything-list@eskimo.com
Sent: Wednesday, February 15, 2006 1:45
AM
Subject: Re: Multiverse concepts in
string theory
Hi Saibal,
Does this not lead one to suspect that
they secretly believe SUSY to be "not even wrong" and yet seek to save face?
My problem is that any scientific theory must be highly falsifiable, otherwise
we are just going back to the days of Scholastic debates...
http://clublet.com/why?AngelsOnTheHeadsOfPins
Onward!
Stephen
- Original Message -
From:
Saibal Mitra
To: Stephen Paul King ; everything-list@eskimo.com
Sent: Tuesday, February 14, 2006 6:20
PM
Subject: Re: Multiverse concepts in
string theory
Stephen,
Theorists are always a bit ahead and they have
already foundways to save SUSY from negative results from the LHC.
Saibal
- Original Message -
From:
Stephen
Paul King
To: everything-list@eskimo.com
Sent: Tuesday, February 14, 2006 1:04
PM
Subject: Re: Multiverse concepts in
string theory
Hi Norman,
It will be a wonderful thing to get a
confirmation by next year but I am afraid that the usual behavior of
theorist will occur: the theory will be re-tinkered so that the particle
masses are too massive to be created by humans. It has been happening
already in astrophysics...
Btw, have you any familiarity with
modeling the dynamics of scalar fields in relativistic situations? I need
some help. ;-)
Onward!
Stephen
- Original Message -
From:
Norman
Samish
To: Everything-list
Sent: Tuesday, February 14, 2006
1:36 AM
Subject: Re: Multiverse concepts in
string theory
Stephen,
As you say, the version of string theorywith an
infinity of universes isan elegant concept. However, when
you say". . . its most fundamental assumption,the existence
of a supersymmerty relation between bosons and fermions, has never even
come close to matching experimental observation,"one could infer
that there is little likelihood that SUSY will ever be shown to
bea good theory.
Thismay change soon.Wikipedia says
"Experimentalists have not yet found any superpartners for known
particles, either because they are too massive to be created in our
current particle accelerators, or because they may not exist at
all. By the year 2007, the Large Hadron Collider at CERN
should be ready for use, producing collisions at sufficiently high
energies to detect the superpartners many theorists hope to
see."
So maybe, in a couple of years, there WILL be
experimental observation supporting SUSY.
I agree that the posts by Hal Finney and Wei Dai are
well said and inspirational. Thanks,
Norman
Re: why can't we erase information?
How would an observer know he is living in a universe in which information is lost? Information loss means that time evolution can map two different initial states to the same final state. The observer in the final state thus cannot know that information really has been lost. - Original Message - From: Wei Dai [EMAIL PROTECTED] To: everything-list@googlegroups.com Sent: Sunday, April 09, 2006 09:11 AM Subject: why can't we erase information? If we consider our observable universe as a computation, it's rather atypical in that it doesn't seem to make use of the erase operation (or other any operation that irreversibly erases information). The second law of thermodynamics is a consequence of this. In order to forget anything (decrease entropy), we have to put the information somewhere else (increase entropy of the environment), instead of just making it disappear. If this doesn't make sense to you, see Seth Lloyd's new book Programming the Universe : A Quantum Computer Scientist Takes On the Cosmos for a good explanation of the relationship between entropy, computation, and information. Has anyone thought about why this is the case? One possible answer is that if it were possible to erase information, life organisms would be able to construct internal perpetual motion machines to power their metabolism, instead of competing with each other for sources of negentropy, and perhaps intelligence would not be able to evolve in this kind of environment. If this is the case, perhaps there is reason to hope that our universe does contain mechanisms to erase information, but they are not easily accessible to life before the evolution of intelligence. It may be a good idea to look out for such mechanisms, for example in high energy particle reactions. However I'm not sure this answer is correct because there would still be competition for raw material (matter and energy) where intelligence can still be an advantage. Anyone have other ideas? --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-list@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list -~--~~~~--~~--~--~---
Re: why can't we erase information?
Yes, I agree. But it could be that information loss is a bit ambiguous. E.g. 't Hooft has shown that you can start with a deterministic model exhibiting information loss and end up with quantum mechanics. Saibal - Original Message - From: Jesse Mazer [EMAIL PROTECTED] To: everything-list@googlegroups.com Sent: Monday, April 10, 2006 03:22 AM Subject: Re: why can't we erase information? Saibal Mitra wrote: How would an observer know he is living in a universe in which information is lost? Information loss means that time evolution can map two different initial states to the same final state. The observer in the final state thus cannot know that information really has been lost. If he is able to figure out the fundamental laws of physics of his universe, then he could see whether or not they have this property of it being possible to deduce past states from present ones (I think the name for this property might be 'reversible', although I can't remember the difference between 'reversible' and 'invertible' laws). For example, the rules of Conway's Game of Life cellular automaton are not reversible, but if it were possible for such a world to support intelligent beings I don't see why it wouldn't be in principle possible for them to deduce the underlying rules. As for the question of why we live in a universe that apparently has this property, I don't think there's an anthropic explanation for it, I'd see it as part of the larger question of why we live in a universe whose fundamental laws seem to be so elegant and posess so many symmetries, one of which is time-symmetry (or to be more accurate, CPT-symmetry, which means the laws of physics are unchanged if you switch particles with antiparticles and flip the 'parity' along with reversing which direction of time is labeled 'the future' and which is labeled 'the past'). Some TOEs that have been bandied about here say that we should expect to live in a universe whose laws are very compressible, so maybe this would be one possible way of answering the question. Jesse - Defeat Spammers by launching DDoS attacks on Spam-Websites: http://www.hillscapital.com/antispam/ --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-list@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list -~--~~~~--~~--~--~---
Re: why can't we erase information?
- Original Message - From: Wei Dai [EMAIL PROTECTED] To: everything-list@googlegroups.com Sent: Tuesday, April 11, 2006 01:46 AM Subject: Re: why can't we erase information? Saibal Mitra wrote: How would an observer know he is living in a universe in which information is lost? Information loss means that time evolution can map two different initial states to the same final state. The observer in the final state thus cannot know that information really has been lost. If the universe allows two different states to evolve into the same final state, the second law of thermodynamics wouldn't hold, and we would be able to (in principle) contruct perpetual motion machines. I don't know why you say this can't be detected by an observer. In theory all we have to do is prepare two systems in two different states, and then observe that they have evolved into the same final state. Of course in practice the problem is which two different states? And as I suggest earlier, it may be that for anthropic reasons one or both of these states is very difficult to access. Yes, in principle you could observe such a thing. But it may be that generic models exhibiting information loss look like model that don't have information loss to internal observers. 't Hooft's deterministic models are an example of this. I'm also skeptical about observers being able to make more efficient machines. The problem with that, as I see it (I haven't read Lloyd's book yet) is as follows. Consider first a model without information loss, like our own universe. What is preventing us from converting heat into work with 100% efficiency is lack of information. If we had access to all the information that is present then you could make an effective Maxwell's Daemon. Lacking such information, Maxwell's Deamon has to make measurements, which it has to act on. But eventually it has to clear it's memory, and that makes it ineffective. To get rid of this problem Maxwell's Daemon would have to be able to reset its memory without changing the state of the rest of the universe. This could possibly be done in an universe with information loss, but that could only work if the Daemon has control over the information loss process. If information loss interferes with the actions of the Daemon, then it isn't much use. You could also think of the possiblity of some ''physical process'' which would be sort of a ''passive Maxwell's Deamon'' that could reduce the entropy in such universe. Using that you could create a temperature difference between two objects. To extract work you now need to let heat flow between the two objects. So, at that stage you need an entropy to increase again. So, to me this doesn't seem to be a generic world in which you have information loss, rather a world in which it is preserved but where it can be overruled at will. The benefits come from that magical power. Saibal - Defeat Spammers by launching DDoS attacks on Spam-Websites: http://www.hillscapital.com/antispam/ --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-list@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list -~--~~~~--~~--~--~---
Re: why can't we erase information?
This thread is still alive! It seems that information can't be erased in this thread either :) I think that information can't be erased because of the way time is (or should be) defined. If you take the observer moment approach to the multiverse, then you have to define a notion of time. That definition will then imply conservation of information. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-list@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list -~--~~~~--~~--~--~---
Re: Smullyan Shmullyan, give me a real example
Einstein seems to have believed in ''immortal observer moments''. In a BBC documentary about time it was mentioned that Einstein consoled a friend whose son had died in a tragic accident by saying that relativity suggests that the past and the future are as real as the present. Saibal From: Russell Standish [EMAIL PROTECTED] To: everything-list@googlegroups.com Sent: Thursday, May 11, 2006 01:07 AM Subject: Re: Smullyan Shmullyan, give me a real example On Wed, May 10, 2006 at 11:13:27PM +0100, Patrick Leahy wrote: On who invented quantum suicide, the following is from the biography of Hugh Everett by Eugene B. Shikhovtsev and Kenneth W. Ford, at http://space.mit.edu/home/tegmark/everett/ Atheist or not, Everett firmly believed that his many-worlds theory guaranteed him immortality: His consciousness, he argued, is bound at each branching to follow whatever path does not lead to death --- and so on ad infinitum. (Sadly, Everett's daughter Liz, in her later suicide note, said she was going to a parallel universe to be with her father...) Sadly, because this is based on a total misunderstanding of QTI, I guess. The reference is to Everett's views in 1979-80, but there is no reason to suppose that Everett had only just thought of it at the time. On a personal note, some time in the '80s I met one of Everett's co-workers who told me that Everett used to justify his very unhealthy lifestyle on exactly these grounds. In our world, Everett died of a heart attack aged 52. I have always assumed that John Bell was thinking along these lines when he commented on Everett's theory: But if such a theory was taken seriously it would hardly be possible to take anything else seriously. (1981, reprinted in _Speakable Unspeakable in Quantum Mechanics). These dates all mesh with Don Page's anecdote about Ed Teller : immortality consequences widely known, but rarely talked about by the early '80s. For that matter, this idea is implicit in Borges' story The Garden of Forking Paths (written before 1941), which provides the epigraph to the DeWitt Graham anthology on The Many Worlds Interpretation. == Dr J. P. Leahy, University of Manchester, Jodrell Bank Observatory, School of Physics Astronomy, Macclesfield, Cheshire SK11 9DL, UK Tel - +44 1477 572636, Fax - +44 1477 571618 Very interesting. Its a shame my manuscript is already at the printers, I would have loved this for my background info on QTI. -- -- -- A/Prof Russell Standish Phone 8308 3119 (mobile) Mathematics0425 253119 () UNSW SYDNEY 2052 [EMAIL PROTECTED] Australia http://parallel.hpc.unsw.edu.au/rks International prefix +612, Interstate prefix 02 -- -- --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-list@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list -~--~~~~--~~--~--~---
Re: Smullyan Shmullyan, give me a real example
From: Patrick Leahy [EMAIL PROTECTED] To: everything-list@googlegroups.com Sent: Friday, May 12, 2006 12:56 PM Subject: Re: Smullyan Shmullyan, give me a real example On Fri, 12 May 2006, Saibal Mitra wrote: Einstein seems to have believed in ''immortal observer moments''. In a BBC documentary about time it was mentioned that Einstein consoled a friend whose son had died in a tragic accident by saying that relativity suggests that the past and the future are as real as the present. I'm sure Einstein would turn in his grave at your quoted expression. An immortal moment is a contradiction in terms, unless it implies a second time which passes as we contemplate first time embedded in 4-D space-time. Unfortunately a lot of popular discussion of space-time implicitly invokes this spurious second time, because it is hard to decouple the language of existence from the language of existence *in time*. To believe, with Einstein, that all points in space-time are equally real (because the relativity of simultaneity means that there is no unique now) is quite the opposite of the nutty idea that all events exist now --- not even wrong, from Einstein's point of view. Einstein actually expressed this view in a letter of condolence to the widow of his old friend Michele Besso. His words are worth quoting accurately: In quitting this strange world he has once again preceded me by just a little. That doesn't mean anything. For we convinced physicists the distinction between past, present, and future is only an illusion, however persistent. Later physicists, in particular John Bell, have pointed out that relativity doesn't *prove* that now is an illusion, it just makes it impossible to identify any objective now. Not that any of this has anything to do with the sort of immortality contemplated by Everett, which is not at all enticing: like the Sibyl in classical myth, his immortality would not be accompanied by eternal youth... a rather horrible fate. Thanks for the correction and the exact quote. I only vaguely remembered what was said in the program. Of course, ''immortal observer moment'' is indeed contradictory. The point is, of course, that ''now'' implies a localization in time just like ''here'' implies localization in space. Just like things that don't exist here but do exist elsewhere are ''real'' so should things that don't exist now anymore but did exist at some time in the past. Saibal --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-list@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list -~--~~~~--~~--~--~---
Re: Reasons and Persons
There must exist a ''high level'' program that specifies a person in terms of qualia. These qualia are ultimately defined by the way neurons are connected, but you could also think of persons in terms of the high-level algorithm, instead of the ''machine language'' level algorithm specified by the neural network. The interpolation between two persons is more easily done in the high level language. Then you do obtain a continuous path from one person to the other. For each intermediary person, you can then try to ''compile'' the program to the corresponding neural network. - Original Message - From: Jesse Mazer [EMAIL PROTECTED] To: everything-list@googlegroups.com Sent: Tuesday, May 30, 2006 02:29 AM Subject: Re: Reasons and Persons Russell Standish wrote: On Mon, May 29, 2006 at 07:15:33PM +1000, Stathis Papaioannou wrote: I don't see why you are so sure about the necessity of passing through non-functional brain structures going from you to Napoleon. After all, there is a continuous sequence of intermediates between you and a fertilized ovum, and on the face of it you have much more in common mentally and physically with Napoleon than with a fertilized ovum. However, technical feasibility is not the point. The point is that *if* (let's say magically) your mind were gradually transformed, so that your We need to be a bit more precise than magically. In Parfit's book he talks about swapping out my neurons for the equivalent neurons in Napoleon's brain. Sure this is not exactly technically feasible at present, but for thought experiment purposes it is adequate, and suffices for doing the teleporting experiment. The trouble I have is that Napoleon's brain will be wired completely differently to my own. Substituting enough of his neurons and connections will eventually just disrupt the functioning of my brain. I agree that Parfit's simple method would probably create a nonfunctional state in between, or at least the intermediate phase would involve a sort of split personality disorder with two entirely separate minds coexisting in the same brain, without access to each other's thoughts and feelings. But this is probably not a fatal flaw in whatever larger argument he was making, because you could modify the thought experiment to say something like let's assume that in the phase space of all possibe arrangements of neurons and synapses, there is some continuous path between my brain and Napoleon's brain such that every intermediate state would have a single integrated consciousness. There's no way of knowing whether such a path exists (and of course I don't have a precise definition of 'single integrated consciousness'), but it seems at least somewhat plausible. Jesse --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-list@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list -~--~~~~--~~--~--~---
Re: Reasons and Persons
John, actually I don't want to do that per se. I think that ultimately we live in a universe described by the very complex ''laws of physics'' that describe the qualia we experience. Perhaps it is better to say that we are such complex universes. We are simulated in a universe described by simple laws of physics. Our brains are simulating us. We shouldn't confuse the hardware with the software Saibal Quoting [EMAIL PROTECTED] [EMAIL PROTECTED]: And why do you want to restrict a 'person' to a cut view of its neurons only? Isn't a person (as anything) part of his ambience - in a wider view: of the totality, with interction back and forth with all the changes that go on? Are you really interested only in the dance of those silly neurons? John M - Original Message - From: Saibal Mitra [EMAIL PROTECTED] To: everything-list@googlegroups.com Sent: Monday, May 29, 2000 9:07 PM Subject: Re: Reasons and Persons There must exist a ''high level'' program that specifies a person in terms of qualia. These qualia are ultimately defined by the way neurons are connected, but you could also think of persons in terms of the high-level algorithm, instead of the ''machine language'' level algorithm specified by the neural network. The interpolation between two persons is more easily done in the high level language. Then you do obtain a continuous path from one person to the other. For each intermediary person, you can then try to ''compile'' the program to the corresponding neural network. - Original Message - From: Jesse Mazer [EMAIL PROTECTED] To: everything-list@googlegroups.com Sent: Tuesday, May 30, 2006 02:29 AM Subject: Re: Reasons and Persons Russell Standish wrote: On Mon, May 29, 2006 at 07:15:33PM +1000, Stathis Papaioannou wrote: I don't see why you are so sure about the necessity of passing through non-functional brain structures going from you to Napoleon. After all, there is a continuous sequence of intermediates between you and a fertilized ovum, and on the face of it you have much more in common mentally and physically with Napoleon than with a fertilized ovum. However, technical feasibility is not the point. The point is that *if* (let's say magically) your mind were gradually transformed, so that your We need to be a bit more precise than magically. In Parfit's book he talks about swapping out my neurons for the equivalent neurons in Napoleon's brain. Sure this is not exactly technically feasible at present, but for thought experiment purposes it is adequate, and suffices for doing the teleporting experiment. The trouble I have is that Napoleon's brain will be wired completely differently to my own. Substituting enough of his neurons and connections will eventually just disrupt the functioning of my brain. I agree that Parfit's simple method would probably create a nonfunctional state in between, or at least the intermediate phase would involve a sort of split personality disorder with two entirely separate minds coexisting in the same brain, without access to each other's thoughts and feelings. But this is probably not a fatal flaw in whatever larger argument he was making, because you could modify the thought experiment to say something like let's assume that in the phase space of all possibe arrangements of neurons and synapses, there is some continuous path between my brain and Napoleon's brain such that every intermediate state would have a single integrated consciousness. There's no way of knowing whether such a path exists (and of course I don't have a precise definition of 'single integrated consciousness'), but it seems at least somewhat plausible. Jesse -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.394 / Virus Database: 268.8.0/353 - Release Date: 05/31/06 -- _ Tele2 - The company that brings you small bills! http://www.tele2.nl --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-list@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list -~--~~~~--~~--~--~---
Re: Teleportation thought experiment and UD+ASSA
I don't understand why you consider the measures of the programs that do the simulations. The ''real'' measure should be derived from the algorithmic complexity of the laws of physics that describe how the computers/brains work. If you know for certain that a computation will be performed in this universe, then it doesn't matter how it is performed. The algorithmic complexity of the program needed to simulate a brain refers to a ''personal universe''. You can think of the brain as a machine that is simulating a virtual world in which the qualia we experience exist. That world also exists independent of our brain in a universe of its own. This world has a very small measure defined by the very large algorithmic complexity of the program needed to specify the brain. Saibal From: Hal Finney [EMAIL PROTECTED] To: everything-list@googlegroups.com Sent: Tuesday, June 20, 2006 06:35 PM Subject: Re: Teleportation thought experiment and UD+ASSA Bruno writes: Hal, It seems to me that you are introducing a notion of physical universe,=20 and then use it to reintroduce a notion of first person death, so that=20 you can bet you will be the one annihilated in Brussels. I should first mention that I did not anticipate the conclusion that I reached when I did that analysis. I did not expect to conclude that teleportation like this would probably not work (speaking figurately). This was not the starting point of the analysis, but the conclusion. The starting point was the framework I have described previously, which can be stated very simply as that the measure of an information pattern comes from the universal distribution of Kolmogorov. I then applied this analysis to specific information patterns which represent subjective, first person lifetime experiences. I concluded that the truncated version which ends when the teleportation occurs would probably have higher measure than the ones which proceed through and beyond the teleportation. Although I worked in terms of a specific physical universe, that is a short-cut for simplicity of exposition. The general case is to simply ask for the K measure of each possible first-person subjective life experience - what is the shortest program that produces each one. I assume that the shortest program will in fact have two parts, one which creates a universe and the second which takes that universe as input and produces the first-person experience record as output. This leads to a Schmidhuber-like ensemble where we would consider all possible universes and estimate the contribution of each one to the measure of a particular first-person experience. It is important though to keep in mind that in practice the only universe which adds non-negligible measure would be the one we are discussing. In other words, consider the first person experience of being born, living your life, travelling to Brussels and stepping into a teleportation machine. A random, chaotic universe would add negligibly to the measure of this first-person life experience. Likewise for a universe which only evolves six-legged aliens on some other planet. So in practice it makes sense to restrict our attention to the (approximately) one universe which has third-person objective events that do add significant measure to the instantiation of these abstract first-person experiences. You agree that this is just equivalent of negating the comp hypothesis.=20 You would not use (classical) teleportation, nor accept a digital=20 artificial brain, all right? Do I miss something? It is perhaps best to say that I would not do these things *axiomatically*. Whether a particular teleportation technology would be acceptable would depend on considerations such as I described in my previous message. It's possible that the theoretical loss of measure for some teleportation technology would be small enough that I would do it. As far as using an artificial brain, again I would look to this kind of analysis. I have argued previously that a brain which is much smaller or faster than the biological one should have much smaller measure, so that would not be an appealing transformation. OTOH an artificial brain could be designed to have larger measure, such as by being physically larger or perhaps by having more accurate and complete memory storage. Then that would be appealing. I think that one of the fundamental principles of your COMP hypothesis is the functionalist notion, that it does not matter what kind of system instantiates a computation. However I think this founders on the familiar paradoxes over what counts as an instantiation. In principle we can come up with a continuous range of devices which span the alternatives from non-instantiation to full instantiation of a given computation. Without some way to distinguish these, there is no meaning to the question of when a computation is instantiated; hence functionalism fails. My
Re: Teleportation thought experiment and UD+ASSA
Hal, thanks for explaining! I think that your approach makes a lot of sense. Applying this to copying experiments, the probability of finding yourself to be the digital copy is: m1/[m1 + m2] where m1 is the measure of the mental experience corresponding to knowing that you are the digital copy and m2 the measure of the mental experience corresponding to knowing that you are still in biological form. I think that for practical implementations m1 = m2 because the digital implementation will just simulate the brain, so the complexity of the translation program would be practically the same. Saibal - Original Message - From: Hal Finney [EMAIL PROTECTED] To: everything-list@googlegroups.com Sent: Wednesday, June 21, 2006 08:49 AM Subject: Re: Teleportation thought experiment and UD+ASSA Saibal Mitra [EMAIL PROTECTED] writes: I don't understand why you consider the measures of the programs that do the simulations. The ''real'' measure should be derived from the algorithmic complexity of the laws of physics that describe how the computers/brains work. If you know for certain that a computation will be performed in this universe, then it doesn't matter how it is performed. I think what you're saying here is that if a mental state is instantiated by a given universe, the contribution to its measure should just be the measure of the universe that instantiates it. And that universe's measure is based on the complexity of its laws of physics. I used to hold this view, but I eventually abandoned it because of a number of problems. I need to go back and collect the old messages and discussions that we have had and put them into some kind of order. But I can mention a couple of issues. One problem is the one I just wrote about in my reply to Russell, the fuzziness of the concept of implementation. In at least some universes we may face a gray area in deciding whether a particular computation, or more specifically a particular mental state, is being instantiated. Philosophers like Hans Moravec apparently really believe that every system instantiates virtually every mental state! If you look at the right subset of the atomic vibrations inside a chunk of rock, you can come up with a pattern that is identical to the pattern of firing of neurons in your own brain. Now, most philosophers reject this, they come up with various technical criteria that implementations have to satisfy, but as I wrote to Russell I don't think any of these work. The other problem arises from fuzziness in what counts as a universe. The problem is that you can write very simple programs which will create your mental state. For example, the Universal Dovetailer does just that. But the UD program is much smaller than what our universe's physical laws probably would be. Does the measure of the UD count as a contribution to every mind it creates? If so, then it will dominate over the contributions from more conventional universes; and further, since the UD generates all minds, it means that all minds have equal measure. To reject the UD as a cheating non-universe means that we will need a bunch of ad hoc rules about what counts as a universe and what does not, which are fundamentally arbitrary and unconvincing. Then there are all those bothersome disputes which arise in this model, such as whether multiple instantiations should add more measure than just one; or whether a given brain in a small universe should get more measure than the same brain in a big universe (since it uses a higher proportion of the universe's resources in the first case). All these issues, as well as the ones above, are addressed and answered in my current framework, which is far simpler (the measure of a mental state is just its Kolmogorov measure - end of story). The algorithmic complexity of the program needed to simulate a brain refers to a ''personal universe''. You can think of the brain as a machine that is simulating a virtual world in which the qualia we experience exist. That world also exists independent of our brain in a universe of its own. This world has a very small measure defined by the very large algorithmic complexity of the program needed to specify the brain. I agree with this, I think. The program needed to specify a mental state a priori would be far larger than the program needed to specify the laws of physics which could cause that mental state to evolve naturally. Both programs make a contribution to the measure of the mental state, but the second one's contribution is enormously greater. The key point, due to Wei Dai, is that you can mathematically treat the two on an equal footing. As you have described it, we have a virtual world with qualia being created by a brain; and you have that same world existing independently as a universe of its own. Those are pretty different in a Schmidhuber type model. The second case is the output of one
Re: A calculus of personal identity
- Original Message - From: Stathis Papaioannou [EMAIL PROTECTED] To: everything-list@googlegroups.com Sent: Friday, June 30, 2006 09:23 AM Subject: Re: A calculus of personal identity Brent Meeker writes: I think it is one of the most profound things about consciousness that observer moments don't *need* anything to connect them other than their content. They are linked like the novels in a series, not like the carriages of a train. It is not necessary that the individual novels be lined up specially on a shelf: as long as they have each been written and exist somewhere in the world, the series exists. But the series exists, as a series, by virtue of the information in them. They are like Barbour's time-capsules; each contains enough references and characters from the others to allow them to be put into order. It's not clear to me what duration obserever moments have - but I don't think they are novel length. I imagine them more like sentences (a complete thought as my English teacher used to say), and sentences *don't* have enough information to allow them to be reconstructed into the novel they came from. A book is the analogy that came to mind, but there is an important difference between this and conscious experience. Books, sentences, words may not need to be physically collected together to make a coherent larger structure, but they do need to be somehow sorted in the mind of an observer; otherwise, we could say that a dictionary contains every book ever written or yet to be written. Moments of consciousness, on the other hand, by their nature contain their own observer. That's why I suggest that OMs are not an adequate ontological basis for a world model. On the other hand, if we include brain processes, or more abstractly, subconscious thoughts, then we would have enough information to string them together. I know some people on this list have attempted world-building with OMs, but my starting point is the less ambitious idea that consciousness can in principle extend across time and space without being specially linked. If a person's stream of consciousness were chopped up into seconds, minutes, days or whatever, using whatever vehicle it takes to run a human mind, and these moments of consciousness randomly dispersed throughout the multiverse, they would all connect up by virtue of their information content. Do you disagree that it would in principle be possible? You can take time evolution as an example. In both classical physics and quantum mechanics, information is preserved. All the information about us was already present in the early universe Saibal --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-list@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list -~--~~~~--~~--~--~---
Re: Interested in thoughts on this excerpt from Martin Rees
- Original Message - From: Hal Finney [EMAIL PROTECTED] To: everything-list@googlegroups.com Sent: Wednesday, July 26, 2006 08:28 AM Subject: Re: Interested in thoughts on this excerpt from Martin Rees The real problem is not just that it is a philosophical speculation, it is that it does not lead to any testable physical predictions. The string theory landscape, even if finite, is far too large for systematic exploration. Our ideas, with an infinite number of possible universes, are even worse. Physicists see acceptance of anthropic explanations as the end of physics because there is no way to make quantitative predictions when there are so many degrees of freedom. I'm not so sure that our ideas are worse. If you read some recent articles, e.g.: http://arxiv.org/abs/astro-ph/0607227 you see that they haven't really formulated rigorous theories about measure, probabilities etc. of the multiverse. It's still very much in the handwaving stage. Saibal --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-list@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list -~--~~~~--~~--~--~---
Re: Russell's book
I think I can prove that QTI as intepreted in this list is false, I'll post the proof in a new thread. The only version of QTI that makes sense to me is this: All possible states exist out there in the multiverse. The observer moments are timeless objects so, in a certain sense, QTI is true. But then you must consider surviving with memory loss. E.g., if I'm diagnosed with a terminal illness, then there is still a branch in which I haven't been diagnosed with that illness. If I'm 100 years old, then I still have copies that are only 20 years old etc. etc. Saibal - Original Message - From: Johnathan Corgan [EMAIL PROTECTED] To: everything-list@googlegroups.com Sent: Tuesday, September 12, 2006 7:43 PM Subject: Re: Russell's book David Nyman wrote: [re: QTI] This has obvious implications for retirement planning in general and avoidance of the more egregious cul-de-sac situations. On the other hand, short of outright lunacy vis-a-vis personal safety, it also seems to imply that from the 1st-person pov we are likely to come through (albeit possibly in less-than-perfect shape) even apparently minimally survivable situations. This struck me particularly forcibly while watching the 9/11 re-runs on TV last night. It's the cul-de-sac situations that interest me. Are there truly any? Are there moments of consciousness which have no logically possible continuation (while remaining conscious?) It seems the canonical example is surviving a nearby nuclear detonation. One logical possibility is that all your constituent particles quantum-tunnel away from the blast in time. This would be of extremely low measure in absolute terms, but what about the proportion of continuations that contain you as a conscious entity? This also touches on a recent thread about how being of low measure feels. If QTI is true, and I'm subject to a nuclear detonation, does it matter if my possible continuations are of such a low relative measure? Once I'm in them, would I feel any different and should I care? These questions may reduce to something like, Is there a lower limit to the amplitude of the SWE? If measure is infinitely divisible, then is there any natural scale to its absolute value? I raised a similar question on the list a few months ago when Tookie Wiliams was in the headlines and was eventually executed by the State of California. What possible continuations exist in this situation? In effect, we are being presented with a kind of 'yes doctor' in everyday life. Do you find that these considerations affect your own behaviour in any way? A very interesting question. If my expectation is that QTI is true and I'll be living for a very long time, I may adjust my financial planning accordingly. But QTI only applies to my own first-person view; I'll be constantly shedding branches where I did indeed die. If I have any financial dependents, do I provide for their welfare, even if they'll only exist forever outside my ability to interact with? -Johnathan --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-list@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list -~--~~~~--~~--~--~---
Proof that QTI is false
QTI in the way defined in this list contradicts quantum mechanics. The observable part of the universe can only be in a finite number of quantum states. So, it can only harbor a finite number of observer moments or experiences a person can have, see here for details: http://arxiv.org/abs/gr-qc/0102010 If there can only be a finite number of observer moments you can only experience a finite amount of time. QED. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-list@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list -~--~~~~--~~--~--~---
Re: Proof that QTI is false
- Original Message - From: Brent Meeker [EMAIL PROTECTED] To: everything-list@googlegroups.com Sent: Wednesday, September 13, 2006 5:47 AM Subject: Re: Proof that QTI is false Saibal Mitra wrote: QTI in the way defined in this list contradicts quantum mechanics. The observable part of the universe can only be in a finite number of quantum states. So, it can only harbor a finite number of observer moments or experiences a person can have, see here for details: http://arxiv.org/abs/gr-qc/0102010 If there can only be a finite number of observer moments you can only experience a finite amount of time. QED. So that would imply that when predicting states at some fixed finite time in the future there is a smallest, non-zero probability that is realizable. So if our prediction, using continuum variables as an approximation, indicates a probability lower than this value we should set it to zero?? Brent Meeker Yes, but you don't have to set anything to zero by hand. What happens is that if there are only a finite number of quantum states there is one which has the smallest non zero probability. Saibal --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Everything List group. To post to this group, send email to everything-list@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/everything-list -~--~~~~--~~--~--~---
Re: Proof that QTI is false
Yes, I agree that you could still have some form of QTI if there are only a
finite number of states. I just don't believe in it, because I don't think
the use of the relative measure is justified in case the observer isn't
conserved. In all other case the absolute measure and the relative measure
lead to the same predictions.
Actually, in standard quantum mechanics, there is an infinity of
observer moments, 2^{\aleph_0} of them in fact.
What you are talking about are various quantum gravity theories, such
as string theory, which appear to have a finite number of observer
moments.
However, even if as observers we are locked into a Nietschian cycle at
some point in time due to finiteness of the number of possible states,
the number will be so large that the practical effects of QTI will
still need to be considered.
Cheers
- Original Message -
From: Russell Standish [EMAIL PROTECTED]
To: everything-list@googlegroups.com
Sent: Wednesday, September 13, 2006 4:31 AM
Subject: Re: Proof that QTI is false
On Tue, Sep 12, 2006 at 11:58:14PM +0200, Saibal Mitra wrote:
QTI in the way defined in this list contradicts quantum mechanics. The
observable part of the universe can only be in a finite number of
quantum
states. So, it can only harbor a finite number of observer moments or
experiences a person can have, see here for details:
http://arxiv.org/abs/gr-qc/0102010
If there can only be a finite number of observer moments you can only
experience a finite amount of time.
QED.
--
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may safely ignore this attachment.
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-~--~~~~--~~--~--~---
Re: Measure of the prisoner
Bruno wrote: - Oorspronkelijk bericht - Van: Marchal [EMAIL PROTECTED] Aan: [EMAIL PROTECTED] Verzonden: woensdag 29 maart 2000 11:40 Onderwerp: Re: Measure of the prisoner Suppose that the simulated prisoner is a ``digital ´´ copy of a real Saibal Mitra wrote: [...] If the simulated time also corresponds exactly to real time then the probability of the prisoner finding himself in the simulated world is almost exactly 1/2. Why ? Even if the simulated time does not correspond to the real time the probability of the prisoner finding himself in the simulated world is 1/2. Unless you solve Jacques Mallah's desperate implementation problem (see the archive or Mallah's URL) you will not be able to use time to define the measure on the prisoner's experiences. From the point of view of the prisonner, if COMP is correct, he cannot make any difference between real or un-real-time. Time (like space) is a construction of the observer's mind and is defined only in a relative way. What you need to do is to defined a notion of first person (or subjective) time *from* the measure on the possible computationnal continuation of the prisoner's mind. Note also that there is no real time in any many-world view of relativistic quantum mechanics (even without COMP). With COMP (which you are using here) there is no real time nor is there any need for such a thing. More on this in the archive at http://www.escribe.com/science/theory/m1726.html Bruno I now think Bruno is right. The measure doesn't depend on t'/t. But, in any case, consistency with other thougth experiments (e.g. simulations within a simulation with another relative time-dilatation factor t''/t') limits how the ratio of the measures can behave as a function of t'/t : m2/m1 = (t'/t) ^ x (m2 is the measure of the simulated prisoner m1 that of the real prisoner, and it takes t seconds to simulate t' seconds of the life of the prisoner). A nonzero value for x can still arise in certain cases. E.g. if one simulates one day of the life of the prisoner with periodic boundary conditions, one has x = 1. To see this, suppose the prisoner is simulated on two different computers, one with t'/t = 1 and the other with t'/t = 1/2. Only one day of the life of the prisoner is simulated. After a simulated time of 24 hours the simulation starts all over again. Then clearly in a time interval of 2 T days, the life of the prisoner is simulated 2 T times on the fast computer and T times on the slow computer. Saibal
(Quantum) suicide not necessary?
Instead of the previously discussed suicide experiments to test variousversions of many-worlds theories, one might consider a different approach. By deleting certain sectors of one's memory one should be able to travelto different branches of the multiverse. Suppose you are diagnosed with a rare disease. You don't have complaints yet, but you will diewithin a year. If you could delete the information that you have thisparticular disease (and also the information that information hasbeen deleted), branches in which you don't have the diseasemerge with the branches in which you do have the disease. So withvery high probability you have travelled to a different branch.
Interesting article
Recently an article appeared on the Los Alamos archive that explains how, for certain systems, dynamics can be derived from probabilistic arguments alone. I think that the formalism developed in the article can be generalised, and used to explain the physical laws we observe without necessarilyinvoking ''compressibility'' of information in our universe. The article can be found at: http://xxx.lanl.gov/abs/math-ph/0008018 Saibal
Re: The Rapidly-Accelerating Computer
Wei Dai wrote: On Thu, Sep 14, 2000 at 01:13:35PM -0400, [EMAIL PROTECTED] wrote: It may be impossible to construct such a machine in our universe, but can we achieve the same results by slowing down the consciousness of the observer observing a conventional computer? In other words, each observer's clock cycle (assuming a computer model for the observer) would double in duration in relation to the computer clock. Could there be such an observer in our universe? I suspect that there can't be because the construction of the observer's clock woud require smaller and smaller energy packets in the presence of constant background noise. Even if a continually slowing observer (CSO) could exist, it's relationship to a normal computer would not be the same as that of a normal observer to a RAC. To a normal observer, there is some finite subjective time in the future when the RAC will have gone through an infinite number of clock cycles, but to the CSO there is no finite subjective for when a normal computer will have gone through an infinite number of clock cycles. This is obvious when you consider that any finite subjective time for the CSO is also a finite objective time. But if as a function of objective time t the subjective time s(t) is such that Lim t --- Infinity s(t) = 1 then after a subjective time of 1 second an infinite amount of objective time will have passed, unless you assume that the CSO can only exist at times s(t) 1 . Saibal
Re: another anthropic reasoning
Wei Dai wrote: This experiment is not a game, since the action of each participant only affects his or her own payoff, and not the payoff of the other player. Actually you can do this with just one participant, and maybe that will make the paradoxical nature of anthropic reasoning clearer. Suppose the new experiment has two rounds. In each round the participant will be given temporary amnesia so he can't tell which round he is in. In round one he will have low measure (1/100 of normal). In round two he will have normal measure. He is also told: If you push button 1, you will lose $9. If you push button 2 and you are in round 1, you will win $10. If you push button 2 and you are in round 2, you will lose $10. According to anthropic reasoning, the participant when faced with the choices should think that he is much more likely to be in round 2, and therefore push button 1 in both rounds, but obviously he would have been better off pushing button 2 in both rounds. I would conclude that it is inconsistent to say that there are two rounds and that in round one the participant has 1/100 of the measure of the second round. If it is certain that there will be two rounds then the measures must be equal. Saibal
Re: Who is the enemy?
Bruno, what did you expect? You should expect Jacques to be a typical American. You know how Americans on opposite sides of an issue tend to behave. E.g. recounting of votes in Florida, pro life versus pro choice... Unthinkable here in Europe! Anyway, there is nothing wrong with Jacques, he is behaving in a way you should expect from the MWI or your theory. Saibal - Original Message - From: Marchal [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Wednesday, September 19, 2001 6:08 PM Subject: Who is the enemy? Jacques Mallah wrote: (I'm currently in North Dakota, but have lived in NYC most of my life. I did not know anyone who was in the WTC.) I told you my relief, but I begin to doubt ! Look at what you write: Recently, of course, I have been more concerned with the destruction caused in NYC by the advocates of suicide and believers in immortality. I understand your concern with NYC. I share with you the concern of those terrible and crual 11 sept. events. Now a pecularity of this war consists in figuring out who is the enemy, exactly. It looks like you have solved that problem too. The enemy are the believers in immortality, the religious people !?! I am fearing amalgamations, like the amalgamations between Muslims and terrorists (to name one which has been done by some). But you are the champion: the enemy are all religious people. The war between atheism and religion !?! Perhaps I should tell you what are, according to G*, the canonical enemies of the sound universal machine. [ ... and here a very long reasoning with lot of thought experiments, or a shorter formal reasoning where the main point consists in distinguishing what G and G* say ... I don't want to bore you and give you at once the result ...]: And it looks like you were almost right. The universal sound machines war is between the agnostic and the *imposed* religion (whatever that religion is, atheism included). The sound machine is maximaly humble, she is agnostic on both her own consistency and her own inconsistency. This entails two sort of dangerous consistent extensions: 1) meeting a machine (perhaps itself) which feels superior, and 2) meeting a machine (perhaps itself) which feels inferior. (Meeting or becoming herself). That reminds me a theory of intelligence I developped years ago (still from G*): a machine is intelligent iff it is not stupid. And a machine is stupid iff either the machine believes itself intelligent or the machine believes itself stupid. [with consistent (resp. inconsistent) in place of intelligent (resp. stupid) those sentences are just rephrasing of particular instantiation of Godel second incompleteness theorem]. The universal sound machine is forever undecided about any of its possible ultimate worldview and, by doubting, never imposes its religion or worldview on different machines. This should not prevent her to react against those imposing-view machines. That's just self-defense. We can respect only those who respect ourselves, and ... reciprocaly. With comp any sound machine is condemned to doubt, forever. A sound machine can neither be a believer in immortality nor be a believer in mortality. The sound machine is forever agnostic on that question. That is forever undecided. (and by consequence forever undecided about comp of course: they can bet, fear or hope for comp and/or for self-soundness, but that's personal). The sound machines can also make reasoning with comp *as an hypothesis*. This is what I find very humanistic about comp: we are necessarily more modest and ignorant about fundamental questions, and thus more open and prudent with other's opinions. At the same time we get tools for studying the geometry of that ignorance and see precisely where matters come from, through the comp act of faith. Precisely but uncertainly. Like any scientific approaches. The consistent computationalist cannot *not* be moderate, like the honnest scientific, which is also a professional doubter. Some people believe that doubting is a sign of lacking confidence in oneself, or even lacking faith. Apparently (with G*) it is the contrary. This is coherent with the apparent lack of doubt of the fanatics, which above all does not even tolerate sign of doubts. Today I guess we have still the choice between a war between moderates and fanatics and a war between fanatics and fanatics. In the second case we loose the war at the start, isn't it? Do you agree with this last statement? Or are you really, Mister the Devil's Advocate, a fanatical atheist? Bruno
Re: FIN insanity
Jacques Mallah wrote: From: Saibal Mitra [EMAIL PROTECTED] There are different versions of QTI (let's not call it FIN). I'm certainly not going to call it a theory. Doing so lends it an a priori aura of legitimacy. Words mean things, as Newt Gingrich once said in one of his smarter moments. The most reasonable one (my version, of course) takes into account the possibility that you find yourself alive somewhere else in the universe, without any memory of the atomic bomb that exploded. I totally ignore the possibility that one could survive an atomic bomb exploding above one's head. My version doesn't imply that your a priory expected lifetime should be infinite. Your version may not imply immortality, but I don't really see how it's different from other versions (and thus why it doesn't). As I have written before, a person is just a computation being implemented somewhere. Suppose that the person has discovered that he suffers from a terminal ilness and he dies (the computation ends). Now in principle the person in question could have lived on if he wasn't diagnosed with this terminal ilness. Somewhere in the multiverse this person exists. Some time ago I wrote (I think on the FoR list) that the transformation from the old dying person to the new person is a continuous one. The process of death must involve the destruction of the brain. At some time the information that the person is dying will be lost to the person. The person might even think he is 20 years old while in reality he is 92. Anyway, the point is that his brain had stored so much information that adding new information would lead to an inconsistency. By dumping some of the information, the information left will be identical to the information in a similar brain somewhere else of a younger person, free from disease. I say: 1) If you are hurt in a car accident and the surgeon performes brain surgery and you recover fully, then you are the same person. OK, that's merely a matter of definition though. 2) You would also be the same person if the surgeon made a new brain identically to yours. I'm not sure what you mean here. The new brain would be the same as the old you, the old one would remain the same, the old one was destroyed, or what? Well, suppose that the damaged brain contains enough information to reconstruct the original one. It doesn't matter if you repair the old one or create a new one. 3) From 2) it follows that if your brain was first copied and then destroyed, you would become the copy. A matter of definition agin, but let me point out something important. If your brain is copied, then there is a causal link between the old brain and any copies. Thus it's quite possible for an extended implementation of a computation to start out in the old brain and end up in the copy, without violating the requirement that implementations obey the proper direct causal laws. 4) From 3) you can thus conclude that you will always experience yourself being alive, because copies of you always exist. I don't see how 4 is supposed to follow from 3. In any case, it's certainly not true that copies of you always exist. Rather, people who are structurally identical do exist, but they are not copies as they are not causally linked. Even if they were linked in the past, they have diverged on the level of causal relationships between your brain parts vs. their brain parts. I don't understand why it is necessary for one person to qualify as a copy of another iff there is a causal link. 5) It doesn't follow that you will experience surviving terrible accidents. If 4 were true, I don't see how 5 could be true. 5) is true because you can survive with memory loss (see above). You would be killed, but copies of you exist that never experienced the accident. Saibal
Re: Travelling to a different universe
I don't see why one would want to go back, but there are still copies left in ordinary universes, there are universes in which the probability to win will return to normal after a while. One should thus be able to go back using a suicide machine. Also one could use memory erasure to go back. Saibal John Mikes wrote: OK, Saibal Mitra, you won. Are you happy now? Can you ever go back? John Mikes Suppose that every week I subject myself to a suicide experiment. I usea suicide machineto win that weeks lottery. After a few years I will have won hundreds of times in succession. Now there exists a class of universes, with a very low measure, in which the laws of physics aresuch that I am guaranteed to win. The probability that I find myself in such a universe will have increased substantially aftereach experiment. After a few years I will be sure to live in such a universe. It would be easy to check, all I would have to do is to buy a ticket and see if I have won without using the suicide machine. Saibal
Re: Immortality
I see that according to you Hal Ruhl qualifies as a copy of Hal Finney. - Oorspronkelijk bericht - Van: jamikes [EMAIL PROTECTED] Aan: [EMAIL PROTECTED] CC: Saibal Mitra [EMAIL PROTECTED]; Hal Ruhl [EMAIL PROTECTED] Verzonden: zondag 9 september 2001 15:06 Onderwerp: Immortality As much as I enjoyed last years's discussions in worldview speculations, I get frustrated by the lately emerged word-playing about concepts used in just different contents from the conventional. May I submit a (trivial) proof for immortality in this sense: Death (of others, meaning not only persons) is a 3rd person (fantasy?), either true or imagined. NOBODY ever experienced his/her own death and the time after such, so immortality is the only thing in consciousness. The world (experienceable worldview) does not include otherwise. To the forgotten things existing in another (branch of?) world: If I 'forgot' something: that dose not necessarily build another world of those things I forgot. Alzheimer patients are not the most efficient Creators. And please do not 'rationalize' about 'near death' and similar fantasies in this respect. Excuse my out-of-topic remark to the topic. John Mikes - Original Message - From: Saibal Mitra [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Sunday, September 09, 2001 6:30 AM Subject: Re: Conventional QTI = False Hal Finney wrote: Saibal writes: According to the conventional QTI, not only do you live forever, you can also never forget anything. I don't believe this because I know for a fact that I have forgotten quite a lot of things that have happened a long time ago. Right, but to make the same argument against QTI you'd have to say, you don't believe this because you have died. But this is not possible. So the analogy is not as good as it looks. You do exist in branches where you have forgotten things, as well as in branches where you remember them. That is true, but I want to make the point that branches where I survive with memory loss have to be taken into account. In the case of a person suffering from a terminal disease, it is much more likely that he will survive in a branch where he was not diagnosed with the disease, than in a branch where the disease is magically cured. The latter possibility (conventional qti) can't be favoured above the first just because the surviving person is more similar to the original person. You could object that in the first case your consciousness is somehow transferred to a different person (you ``jump´´ to a different branch that separated from the dying branch before you were diagnosed), but I would say that the surviving person has the same consciousness the original person would have if you cured his disease and erased all memory of having the disease. Saibal
Re: Journals
Try Foundation of Physics Letters! Saibal Russel wrote: As many of you are aware, I have been attempting to publish Why Occams Razor for about 18 months now. In September, it will have been two years since I wrote the paper. I first tried Phys Rev - which rejected it on editorial policy grounds (no fundamentals of QM please) then Annals of Physics (who published Tegmark's paper). Annals of Physics found one referee, who completely failed to understand the main point of the paper, and was not prepared to discuss it. The ended up rejecting the paper because they couldn't find any other referees to handle it. In February of this year, I have submitted it to Journal of Theoretics, for two reasons: i) It is an Internet Journal, with open access to its archives. Philosophically, I am in favour of free open access to journals since a) scientists do not charge to write articles, b) scientists do not charge to referee articles, c) scientific editors often do not charge to edit journals, or the editors are subsidised by a society or institution d) the Internet reduces distributions charges to practically zero. I have been a long supporter of the journal Complexity International for these reasons, although its subject matter is not so relevant for this group. It perhaps does not have the cachet of other journals, but I believe so strongly in this principle, I would like to raise its quality by contributing good articles. ii) J. Theoretics editorial policy is summed up by: Unlike most journals were the theory has to be validated or invalidated by the article, the Journal of Theoretics must use a different process due to the nature of the subject matter. Because a theory by definition is a hypothesis not yet proven, we must show that the premises, logic, or use of language of the article submitted contains a significant error in order for a rejection to occur. ie something obviously wrong gets rejected, but otherwise ideas of merit get to see the light of day. However, it seems that Internet journals do not have a speedier refereeing process. It galls me a bit, since I've always turned around papers I've refereed within a couple of weeks, that other referees may not be taking the refereeing process seriously. I have a question in light of this for the group. Come September (2nd anniversary of Why Occams Razor), if I've had no joy with J. Theoretics, I would like to try another journal. All I ask is that my paper be properly peer reveiwed. Does anyone have any suggestions? What about Teorie e Modelli? Cheers -- -- Dr. Russell StandishDirector High Performance Computing Support Unit, Phone 9385 6967, 8308 3119 (mobile) UNSW SYDNEY 2052 Fax 9385 6965, 0425 253119 () Australia[EMAIL PROTECTED] Room 2075, Red Centre http://parallel.hpc.unsw.edu.au/rks International prefix +612, Interstate prefix 02 -- --
Re: Travelling to a different universe
I had the set of all possible universes in mind. But, as I wrote earlier (in August), the set of all possible universes is contained in the MWI. The reason is that there is a nonzero probability that you are be simulated by a computer. This computer could run any program. Saibal Charles Goodwin wrote: I can't see this. For one thing, you can't 'travel' to other universes with different laws of physics, at least not according to the MWI. More to the point, assuming quantum suicide works, you will find yourself in one of the sheaf of universes which has split off from the one you started in. This is true anyway, according to MWI, but if you also use quantum suicide you limit your existence to a small subset of that sheaf (the subset in which you won the lottery, for example). Since you only experience universes which are physically possible continuers of the universe you started in, you keep the same laws of physics. So - you can't journey to a universe in which the laws of physics are X by using quantum suicide to select versions of yourself for which X is true; you can only limit your existence to universes in which X happens to be true. Always assuming that quantum suicide actually works (as Larry Niven said about the matter transmitter which destroys you at point A and creates a perfect copy at point B, I wouldn't ride in the damn thing). Charles - Original Message - From: Saibal Mitra [EMAIL PROTECTED] To: everything [EMAIL PROTECTED] Cc: FoR [EMAIL PROTECTED] Sent: Monday, December 24, 2001 2:48 AM Subject: Travelling to a different universe Suppose that every week I subject myself to a suicide experiment. I use a suicide machine to win that weeks lottery. After a few years I will have won hundreds of times in succession. Now there exists a class of universes, with a very low measure, in which the laws of physics are such that I am guaranteed to win. The probability that I find myself in such a universe will have increased substantially after each experiment. After a few years I will be sure to live in such a universe. It would be easy to check, all I would have to do is to buy a ticket and see if I have won without using the suicide machine. Saibal [Non-text portions of this message have been removed] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ Yahoo! Groups Sponsor -~-- Access Your PC from Anywhere - Full setup in 2 minutes - Free Download http://us.click.yahoo.com/1GUySC/E6eDAA/ySSFAA/pyIolB/TM -~- Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
Re: Variations in measure
Russel wrote: Saibal Mitra wrote: Hal wrote: One of the concepts we have explored is that all universes and hence all minds exist, but that some observer-moments have greater measure than others. This may help to explain why we observe the kind of universe that we do, because we must be observer-moments that have relatively large measure. I wonder if it would be possible for the measure of an individual to vary over the course of his lifetime. We do expect the measure to fall as he ages, as he comes to occupy fewer and fewer universes. However there may be other ways that his measure could change. For example, suppose he took a drug which made his mental processes become confused. He was no longer sure of basic facts about himself and the universe. This mental state would no longer be bound to one specific universe. Instead, a large collection of distinct universes could be consistent with this mental state. These observer-moments might therefore have larger measure, since they would correspond to a larger part of the multiverse. In general, one might expect those minds with less observational power and less specific knowledge and understanding of the universe to have larger measure. Does this have any implications for the use of the all-universe hypothesis to explain and predict our observations? Yes it does. In particular it explains why we are of finite age, contrary to what one would naively expect from qti. As I have written some time ago qti needs to be modified precisely because of the effect you describe above. The analogy with the universal prior favoring simpler universes is interesting. Saibal Are you implying that we will not see some arbitrary large age because our minds will become confused (senile perhaps), and so our self-perceived age might slip back? Or are you saying that the effect of measure decreasing as a function of psychological time implies that we must start from a simple nascent state of age 0, then experience all intermediate states before reaching some enormous age? This later statement is entirely consistent with the conventional form of QTI. The former is an interesting point, but I'm not entirely sure how to formalise it properly (perhaps as a corollory of the second law of thermodynamics?). I mean it in the former sense. We could become senile and become identical to a younger person (probably a baby at sleep) and that way evade death, or it could happen as a result of massive head injuries. I think that the probability of ``surviving´´ in this discontinuous way (on the long run) is far larger than in a continuous way, as the conventional QTI seems to imply. Saibal
Re: quantum immortality
Yes, you can save the ``conventional´´ quantum immortality theorem by extending the definition of a person, but is a person with an astronomical amount of data stored in his brain plus all of my memory really me? I would say not. I would go even further: The person I was when I was 3 years old is dead. He died because too much new information was added to his brain. A different version of quantum immortality is more reasonable (meaning that it has a much higher probability than the conventional version). The process of death necessarily involves the destruction of the brain. The dying person thus looses information. At a certain point the information that he is dying is lost to the person. At that time the information still present in the brain will be exactly identical to the information present in another person's brain somewhere else in the multiverse. Let's call him X. There will be an infinite number of X's There is then a high probability that X is not dying, that in fact he is almost identical to the original person at a younger age. The dying person thus walks away in X's body. Saibal Russel wrote: A reasonable argument, but it does have a flaw. I vaguely remember a discussion on the evrything list related to the finiteness of someone's memory, which I think is the same argument. Why assume that person retains a constant configuration throughout er life? Could not memory be augmented over time to allow the person to get older unboundedly? Cheers Saibal Mitra wrote: The total number of states a certain person can be in is bounded. One might argue that according to quantum mechanics a certain person will always find himself alive, but all that means is that that person will always find himself in one out of a finite number of states. This implies that there can be no continuous evolution such that the person becomes older and older ad infinitum. Saibal [Non-text portions of this message have been removed] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ Dr. Russell Standish Director High Performance Computing Support Unit, Phone 9385 6967 UNSW SYDNEY 2052 Fax 9385 6965 Australia [EMAIL PROTECTED] Room 2075, Red Centre http://parallel.hpc.unsw.edu.au/rks Yahoo! Groups Sponsor Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
Re: fin insanity
Charles Goodwin wrote: -Original Message- From: Saibal Mitra [mailto:[EMAIL PROTECTED]] As I have written before, a person is just a computation being implemented somewhere. Suppose that the person has discovered that he suffers from a terminal ilness and he dies (the computation ends). Now in principle the person in question could have lived on if he wasn't diagnosed with this terminal ilness. Somewhere in the multiverse this person exists. Some time ago I wrote (I think on the FoR list) that the transformation from the old dying person to the new person is a continuous one. The process of death must involve the destruction of the brain. At some time the information that the person is dying will be lost to the person. The person might even think he is 20 years old while in reality he is 92. Anyway, the point is that his brain had stored so much information that adding new information would lead to an inconsistency. By dumping some of the information, the information left will be identical to the information in a similar brain somewhere else of a younger person, free from disease. Hmm.and this is a simpler theory, with more explanatory power, than that people are just material objects which eventually wear out? People are material objects, but the materials out of which people are made don't matter. If your neurons were replaced by artifiicial ones that would function in the same way, would you not be the same person? You would answer any question in the same way as the original version of you would. I conclude that it is the computation that is performed by your brain that generates you. The materials don't matter. I could just as well generate you by a primitive analog computer. What matters is the computer program that is running on the machine, not the machine itself. If you believe that all possible universes exist (universes that can be generated by a computer program), then you ``always´´ exist in some universe, because, by definition, you are a computer program. So, I would say that you will always find yourself alive somewhere. But it is interesting to consider only our universe and ignore quantum effects. Even then you will always find yourself alive somewhere, but you won't find yourself becoming infinitely old (see above). Because this is a classical continuation of you, it is much more likely than any quantum continuation that allows you to survive an atomic bomb exploding above your head. Saibal
Re: UDA last question (was UDA step 9 10).
Questions 1) and 1a) have been answered in this article: http://xxx.lanl.gov/abs/math-ph/0008018 Saibal Joel wrote: Bruno and fellow Everythingers... Sorry I've been disconnected for a while. I think Bruno's last message has really helped me to understand the Universal Dovetailer. Some of those computations will generate the 3-states corresponding to my preparing coffe 1-state. Because we accept comp. Now if I prepare a cup of coffee, my brain will go through a sequence of states (third person describable computational state, at the right level of description of myself). and I have pick one of those state---like in a duplication experiment). So the UD generates that state eventually (by going through a computation which emulates my doing or dreaming of doing that cup of coffe). So the Universal Dovetailer simply enumerates all possible states for me. (Whatever me is, is unimportant). And somehow, these states are joined by their similarity to one another, which allows (virtual) motion from one state to the next. So, if I am currently sitting in the state of sitting at my desk, I have several realities branching off from this one where in the next moments I am rising from my chair, or still sitting at my desk, or petting a white rabbit. But I am left with one nagging question: 1) Where is Time? 1a) What governs the trajectory of one's awareness through all his/her possible states? 1b) What defines the current state? 1c) How do I get from one state to another? 1d) Isn't this awareness, and its motion path necessarily outside those states and the Universal Dovetailer? Since I am into cellular automata, I always assumed that time is implemented naturally... by the automaton... from one tick to the next - just like a movie. Can we really assume UD* exists? Doesn't it take Time to execute UD? Joel
Re: Provable vs Computable
George Levy wrote: [EMAIL PROTECTED] wrote: Example: a never ending universe history h is computed by a finite nonhalting program p. To simulate randomness and noise etc, p invokes a short pseudorandom generator subroutine q which also never halts. The n-th pseudorandom event of history h is based on q's n-th output bit q(n) which is initialized by 0 and set to 1 as soon as the n-th element of an ordered list of all possible program prefixes halts. Whenever q modifies some q(n) that was already used in the previous computation of h, p appropriately recomputes h since the n-th pseudorandom event. Such a virtual reality or universe is perfectly well-defined. Such a universe would violate Bell' inequality theorem. Quantum randomness cannot be simulated by hidden variables. We have to move beyond realism..to get a model of objective reality we must first develop a model of consciousness. George I disagree. Hidden variables are indeed excluded, but that doesn't mean that deterministic models proposed by Jürgen or 't Hooft are in conflict with Bell's theorem. In the case of the model proposed by 't Hooft, you have a universe that is very chaotic. Quantum mechanics arises in a statistical description of the theory. Particles such as electrons, photons etc. don't describe the degrees of freedom of the original deterministic theory, but rather they arise only in the statistical description of this theory. In other words: Mach was right in not believing that atoms exist. In the case of the two slits experiment, a hidden variable theory would tell you through what particular slit an elecron travelled, and this is not possible. Okay, but does the electron exist in the first place? I think not. The electron is just a mathematical tool that allows you to calculate probabilities and is unphysical, just like virtual particles and ghosts in Feynman diagrams. Why believe in electrons, but not in the Fadeev-Popov ghost? Saibal
Re: The Simulation Argument
A proper calculation using Bayes' theorem is missing in the article. The conclusion is false. E.g. let's assume that (2) and (3) are false. So, we know with almost 100% certainty that we are not living in a simulation, and we know with almost 100% certainty that a posthuman civilization is going to run significant number of simulations of their evolutionary history. Concluding that (1) must be true is thus precisely the Doomsday argument which is false because of improper Bayesian reasoning: The principle of indifference is used while the self indicating assumption is rejected. This is a logical inconsistency which leads to erroneous conclusions. Saibal Nick Bostrom wrote: ``I have just finished a paper (which had been existing in a half-baked form for much too long) that might be of interest to the list members. It has its own website at http://www.simulation-argument.com (which also contains a few related resources). Are You Living In a Computer Simulation? Nick Bostrom (2001) ABSTRACT. This paper argues that at least one of the following propositions is true: (1) the human species is very likely to go extinct before reaching a posthuman stage; (2) any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history (or variations thereof); (3) we are almost certainly living in a computer simulation. It follows that the transhumanist dogma that there is a significant chance that we will one day become posthumans who run ancestor-simulations is false, unless we are currently living in a simulation. A number of other consequences of this result are also discussed.´´
Re: The infinite list of random numbers
All arrangemets are equally likely, but the probability is, of course, zero. So with probability one you don't get only zeros. There is a theorem that says that any finite arbitrary configuration will appear an infinite number of times in an infinite random sequence with probability one. Saibal Neil Lion wrote: It's undefinable. You're just as likely to get all zeros, or all ones, as you are to get any arrangement of numbers you care to mention (or can mention); the probability being 0 for each, I suppose. The difference is, there are some infinite binary strings of numbers you cannot define without an infinite description (semantic paradoxs aside).. which one assumes, are 'truly' random. From: Norman Samish [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject: The infinite list of random numbers Date: Thu, 08 Nov 2001 20:41:30 -0800 Suppose an ideal random number generator produces, every microsecond, either a zero or a one and records it on a tape. After a long time interval one would expect the tape to contain a random mix of zeroes and ones with the number of zeroes equal to the number of ones. Is this necessarily true? Is it possible that, even after an infinite time had passed, that the tape could contain all zeroes or all ones? Or MUST the tape contain an equal number of zeroes and ones? Why? If you have a reference dealing with this topic, please let me know. Thanks, Norm Samish _ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp
Re: Conventional QTI = False
Hal Finney wrote: Saibal writes: According to the conventional QTI, not only do you live forever, you can also never forget anything. I don't believe this because I know for a fact that I have forgotten quite a lot of things that have happened a long time ago. Right, but to make the same argument against QTI you'd have to say, you don't believe this because you have died. But this is not possible. So the analogy is not as good as it looks. You do exist in branches where you have forgotten things, as well as in branches where you remember them. That is true, but I want to make the point that branches where I survive with memory loss have to be taken into account. In the case of a person suffering from a terminal disease, it is much more likely that he will survive in a branch where he was not diagnosed with the disease, than in a branch where the disease is magically cured. The latter possibility (conventional qti) can't be favoured above the first just because the surviving person is more similar to the original person. You could object that in the first case your consciousness is somehow transferred to a different person (you ``jump´´ to a different branch that separated from the dying branch before you were diagnosed), but I would say that the surviving person has the same consciousness the original person would have if you cured his disease and erased all memory of having the disease. Saibal
Re: Journals
Correction: the journal is called Foundations of Physics.
Re: Predictions duplications
Hal Finney wrote: Juergen Schmidhuber writes: But there is no uniform prior over all programs! Just like there is no uniform prior over the integers. To see this, just try to write one down. I think there is. Given a program of length l, the prior probability is 2^(-l). (That is 2 to the power of negative l.) The length of a program is defined by interpreting it using self-delimiting rules as is customary in the AIT analysis of Greg Chaitin. This doesn't seem to be very uniform to me. Maybe you mean that with the above prior the probability for a bit, drawn randomly from the set of all programs, to be 1 is 1/2 ? Saibal Saibal
Re: existence of stars
You'll have to ask Bruno, because that's what he wrote. On 01-Jun-01, Saibal Mitra wrote: BTW, do you know that Godel wrote a formalisation in the modal logic system S5 of St. Anselm proof of the existence of God? (I'm not sure there is any evidence that Godel takes his proof seriously, but it is a nice little piece of exact and very modest theology. See Vol 3 of the complete work of Godel edited by Feferman Al.). My opinion? Well I don't believe in S5 :-)´´ Could you expand on I don't believe in S5? Just curious. Brent Meeker El sueño de la razón produce monstruos. --Francisco de Goya
Re: Introduction (Digital Physics)
Joel wrote: This may be true, but has anyone here (or anywhere else) ever checked to see that we can't program the universe exactly with simple algorithms? I think this is something new. (Check out what Stephen Wolfram has been doing lately: http://www.wolframscience.com) Everyone's talking about quantum consciousness and other nebulous words, but it seems no one has tried to build the universe from the ground up - on absolute principles and no uncertainties. Now, I know I'm not asking everyone to give up their most cherished beliefs and all their hard work forever. I'm just asking for SOMEONE to stop and take a look with me to see if we haven't missed something really simple - something so obviousthat everyone just dismissed it without asking, Why not? Maybe it's not as hard as we think. Maybe we CAN obtain some real, final answers. It's just crazy enough to work! Joel Interestingly 't Hooft (one of the Nobel-Prize winners of 1999) has formulated deterministic models that reduce to quantum mechanics when described statistically. See e.g. this article: ``How Does God Play Dice? (Pre-)Determinism at the Planck Scale´´: http://xxx.lanl.gov/abs/hep-th/0104219 Saibal
Re: FIN
Jacques Mallah wrote: From: Saibal Mitra [EMAIL PROTECTED] Jacques Mallah wrote: `` I have repeated pointed out the obvious consequence that if that were true, then a typical observer would find himself to be much older than the apparent lifetime of his species would allow; the fact that you do not find yourself so old gives their hypothesis a probability of about 0 that it is the truth. However, they hold fast to their incomprehensible beliefs.´´ According to FIN, however, the probability of being alive at all is almost zero, which contradicts our experience of being alive. Whatchya mean? I wouldn't mind acquiring a new argument against FIN to add to the ones I give, but your statement doesn't appear to make any sense. You wrote earlier that consciousness can't be transferred to a copy. But consciousness isn't transferred, the copies had the same consciousness already because they were identical. I would say: I exist because somewhere I am computed. You appear to say that (forgive me if I am wrong) I must identify myself with one computation. Even an identical computation performed somewhere else will have a different identity. My objection is that the brain is constantly changing due to various processes. The typical timescales of these processes is about a millisecond. FIN thus predicts that I shouldn't find myself alive after a few milliseconds. Saibal
Re: Travelling to a different universe
Bruno wrote: Saibal Mitra wrote: Now there exists a class of universes, with a very low measure, in which the laws of physics are such that I am guaranteed to win. The probability that I find myself in such a universe will have increased substantially after each experiment. After a few years I will be sure to live in such a universe. It would be easy to check, all I would have to do is to buy a ticket and see if I have won without using the suicide machine. Just do the computation. At each suicide you will survive in the nearer world from the one you left. That is: the more normal world relatively to you. Of course you will be sure that you live in such a universe, but you will be wrong. If you stop to use the suicide machine you will stop winning (unless you are using explicitely the suicide machine for filtering just a world where you win without suicide machine, but then that is an another experiment). Look at the iteration 64 times of simple self-duplication WM. Among the 2^64 resulting person, one will believe ending up always at W, but if you iterate *again* 32 times you know that this one will have 2^32 - 1 descendant knowing that the expection was wrong, and only one believing (more and more) having been magically linked to Washington. There is a selection effect by the very use of the suicide machine. In the usual WM experiment this doesn't occur, so let's modify it slightly. First I measure the z-component of a spin ½ particle is measured 1000 times in succesion. Provided I don't find 1000 times spin up I will perform the usual WM experiment, otherwise I will only make copies that end up in Washington. Suppose you use the suicide machine to select W ten thousand times in a row, what would the probability be that I had found 1000 times spin up? Saibal
Re: Conventional QTI = False
I just argue that to compute the probability distribution for your next experience, given your previous ones, you must also consider continuations were you suffer memory loss. QTI fails to do so and it is precisely this that leads to the the prediction that you should find yourself being infinitely old, or that you should live for arbitrary long. If you are severly injured in an accident and dying, then the probability that you will survive in a branch where the accident never happened is much larger than living on in a branch where the accident did happen. That continuations with memory loss are important can be verified ``experimentally´´ (I don't remember everything that has happened to me). There are also continuations of me that never forget anything. I am not one of them. Saibal Russell Standish wrote: Never heard of this reasoning before. Can you expand please? This doesn't appear to be related to the problem of being required to forget how old you if you are immortal in a physical human sense. Cheers Saibal Mitra wrote: According to the conventional QTI, not only do you live forever, you can = also never forget anything. I don't believe this because I know for a = fact that I have forgotten quite a lot of things that have happened a = long time ago. Saibal -- -- Dr. Russell StandishDirector High Performance Computing Support Unit, Phone 9385 6967, 8308 3119 (mobile) UNSW SYDNEY 2052 Fax 9385 6965, 0425 253119 () Australia[EMAIL PROTECTED] Room 2075, Red Centre http://parallel.hpc.unsw.edu.au/rks International prefix +612, Interstate prefix 02 -- --
QTI/FIN
Jacques Mallah wrote: `` I have repeated pointed out the obvious consequence that if that were true, then a typical observer would find himself to be much older than the apparent lifetime of his species would allow; the fact that you do not find yourself so old gives their hypothesis a probability of about 0 that it is the truth. However, they hold fast to their incomprehensible beliefs.´´ According to FIN, however,the probability of being alive at all is almost zero, which contradicts our experience of being alive. Saibal
Re: FIN insanity
Charles Goodwin wrote: -Original Message- From: Jacques Mallah [mailto:[EMAIL PROTECTED]] On the other hand I can't see how FIN is supposed to work, either. I *think* the argument runs something like this... Even if you have just had, say, an atom bomb dropped on you, there's still SOME outcomes of the schrodinger wave equation which just happen to lead to you suriviving the explosion. Although these are VERY unlikely - less likely than, say, my computer turning into a bowl of petunias - they do exist, and (given the MWI) they occur somewhere in the multiverse. For some reason I can't work out, all the copies who are killed by the bomb don't count. Only the very very very (etc) small proportion who miraculously survive do, and these are the only ones you personally experience. Is that a reasonable description of FIN? Ignoring statistical arguments, what is wrong with it? There are different versions of QTI (let's not call it FIN). The most reasonable one (my version, of course) takes into account the possibility that you find yourself alive somewhere else in the universe, without any memory of the atomic bomb that exploded. I totally ignore the possibility that one could survive an atomic bomb exploding above one's head. My version doesn't imply that your a priory expected lifetime should be infinite. Death involves the destruction of your brain. But there are many brains in the universe which are almost identical to yours. Jacques says that you can't become one of them. I say: 1) If you are hurt in a car accident and the surgeon performes brain surgery and you recover fully, then you are the same person. 2) You would also be the same person if the surgeon made a new brain identically to yours. 3) From 2) it follows that if your brain was first copied and then destroyed, you would become the copy. 4) From 3) you can thus conclude that you will always experience yourself being alive, because copies of you always exist. 5) It doesn't follow that you will experience surviving terrible accidents. Saibal
Re: Conventional QTI = False
QTI, as formulated by some on this list (I call this conventional QTI), is supposed to imply that you should experience becoming arbitrarily old with probability one. It is this prediction that I am attacking. I have no problems with the fact that according to quantum mechanics there is a finite probability that bullets fired from a machine gun toward you will all tunnel through your body. Or, that if you are thrown into a black hole (Russell Standish's example), you might be emitted from the black hole as Hawking radiation. The mistake is that QTI ONLY considers certain branches were you survive without memory loss, other branches are not considered. This leads to the paradox that you should experience yourself being infinitely old etc.. Saibal Charles Goodwin wrote: -Original Message- From: Saibal Mitra [mailto:[EMAIL PROTECTED]] In the case of a person suffering from a terminal disease, it is much more likely that he will survive in a branch where he was not diagnosed with the disease, than in a branch where the disease is magically cured. The latter possibility (conventional qti) can't be favoured above the first just because the surviving person is more similar to the original person. I don't understand this argument. The person survives (according to QTI) in both branches. In fact QTI postulates that an infinite number of copies of a person survives (although the *proportion* of the multiverse in which he survives tends to zero - but that is because the multivese is growing far faster than the branches in which a person survives). QTI postulates that ALL observer moments are part of a series (of a vast number of series') which survive to timelike infinity. You could object that in the first case your consciousness is somehow transferred to a different person (you ``jump´´ to a different branch that separated from the dying branch before you were diagnosed), but I would say that the surviving person has the same consciousness the original person would have if you cured his disease and erased all memory of having the disease. That isn't necessary (according to QTI). The multiverse is large enough to accomodate an uncountable infinity of branches in which a given person survives from ANY starting state, as well as a (larger) uncountable infinity in which he doesn't. Charles
Re: existence of stars
Bruno wrote: Saibal wrote: (complete message below for the FORers) Can't we prove that stars (and for that matter anything we observe) exist in at least some universes? But does some universes exists ? To tell you frankly I have a problem with the word universe. I guess you take it as meaning the set (let us say) of all what exists. But then I want to distinguish things which really exists from things which are only distinguished from a relative observer point of view. Tell me how you draw the line. Is there a line? The Great Programmer can presumably compute certain correlations between our obserations of what we think is a star and the state of the observed system itself. As I see it the Great Programmer outputs descriptions, including descriptions of an astronomer observing a star. Why can't the Great Programmer check the description of the astronomer of a star against his own description? Since we have identical copies in those universes, it really doesn't matter. Why ? Suppose I love Moscow and that I am duplicated from Brussels to both Washington and Moscow. And suppose that after that event I wake up in Washington. I hope you understand I am not happy. From time to time I get consolating words by my doppelbrother phones from Moscow. But still ... What I meant was that the observer should have an exactly identical copy in a universe in which stars do exist. So the observer can't tell if stars do or don't exist, but it doesn't matter because he is exactly identical to an observer observing a real star. In your example you should replace Moscow by a virtual reality representation of Moscow. One copy of you travels to the real Moscow, the other copy is a digital version of you that is sent to the cyber-version Moscow. Suppose that we didn't tell you that we would make a digital copy of you. In that case your digital copy would think he is in ``real´´ Moscow. It is important for the stellist and galaxies lovers that stars and galaxies remains existing in the universes as seen by the really vast majority of their vast number of doppelbrothers and sisters ... This gives the degree of solidity. It makes worth acting following personal thought, respecting the ten thousand counterfactuals and apparent causalities. The moral I would draw from MW or comp (you know I think comp - MW), is that if you are enthusiast (let us say) and if you want to *stay* enthusiast, then you have no better means that trying to share that enthusiasm with the most vast possible collection of doppelbrothersisters. No? Yes but shouldn't all the ``oppelbrothersisters´´ be identified? Saibal
