Re: Quantum accident survivor
David wrote: Furthermore if I witness a crash where someone dies can I assume that the victim will survive in their own world so far as at least one quantum branch of survivability seems possible? David Kwinter In case, after the crash, there is somebody who is really dying (and who does not believe in MWI) you can also try this desperate procedure. - Measure on the dying subject, at the 'right' moment, that is to say when he is 'really' dying, the projection operator on the state 'psi'; - There are chances that the state of the dying subject will become 'psi'; - Then measure whether the resulting dying subject, in the state 'psi', is alive or dead; - There are chances it will turn out to be alive; - You can also repeat this procedure more times, in case of necessity.
Re: Quantum accident survivor
- Measure on the dying subject, at the 'right' moment, that is to say when he is 'really' dying, the projection operator on the state 'psi'; Of course this state 'psi' would be a superposition of the kind 1/sqrt2 (|live + |dead) or, better, 1/sqrt2 (|live + exp(i phase)|dead)
JOINING post
Hi, My name is Eric Cavalcanti, and I am joining this list. As was solicited in the website, I am sending this Joining post with details of my background. I am a physicist, recently received my MSc in atomic physics. I have been participating in the Fabric of Reality list for some time, so I have some familiarity (but no extensive knowledge) with some of the topics discussed in this list... Seems the discussions here are also very interesting. Regards, -Eric.
Re: Quantum accident survivor
Hello Hal, Hal Finney wrote: You can indeed choose to believe that as long as any version of yourself continues in any universe, then you will consider yourself to still be alive. You could also choose the contrary, that if the total measure (ie. probability) of your survival is extremely small, that you are dead. How is this different from the current situation? Isn't your measure extremely small compared with the rest of the multiverse already? Wouldn't this mean that mean you're already dead by this definition? If so then I'm not really expecting a reply :-) Matt. When God plays dice with the Universe, He throws every number at once...
Re: Quantum accident survivor
Hi Benjamin, Benjamin Udell wrote: Assume I survive a car/plane crash which we assume could have many different quantum outcomes including me (dead || alive) Since I was the same person (entire life history) up until the crash/quantum 'branch' - then can't I assume that since there was at least one outcome where I survived, that TO ME I will always survive other such life/death branches? Furthermore if I witness a crash where someone dies can I assume that the victim will survive in their own world so far as at least one quantum branch of survivability seems possible? Yes, this is Quantum Immortality in a nutshell. If the MWI is correct, it is impossible to die from a subjective point of view. Hooray! Survive as what, though? And in what condition? I know from personal experience that one does not always experience oneself in that world-branch in which one is in tip-top shape. Reminds me of the ancient Greek myth of the goddess whose mortal lover was granted immortality at her request by Zeus, but not eternal youth, because it didn't occur to the goddess to ask Zeus to grant her lover that too. So the lover never died, but grew ever older, more wrinkled bent, till he became a grasshopper. This is the story of Tithonos and Eos. A similar thing happened to Sibyl, too. Perhaps QI imposes some kind of limit on how physically decrepit one can actually get. Another possibility is that QI does not say that it is impossible to lose consciousness, it says that it is impossible to lose it forever. So perhaps really all it does is guarantee some kind of afterlife (in the most physically likely set of circumstances where that can occur). Matt. When God plays dice with the Universe, He throws every number at once...
Re: a possible paradox
These models with topological non-local features may not actually have outsides by the same token that the Mobius band only has one side, get it? Max Tegmark is a nice kid but he does not seem to deal very well with his own finitude ! I am sure he is not the only one... -Joao Leao Norman Samish wrote: To repeat Tegmark's rhetorical question (and he's probably not the originator), If the multiverse is finite, what's outside it's edge? Norman - Original Message - From: Mirai Shounen [EMAIL PROTECTED] To: Federico Marulli [EMAIL PROTECTED]; [EMAIL PROTECTED] Sent: Thursday, October 30, 2003 1:14 PM Subject: Re: a possible paradox Actually I wasn't thinking about physically impossible things happening very rarely (QM) but only about regular physics vs probability of things happening. If you consider quantum mechanics you are right in an infinite universe there could be areas in which physics just happens to work very differently, people there would formulate very different physical laws (if people could evolve, or spontaneously appear). So if the universe is infinite, it doesn't make much sense to talk about laws of physics. Still there need to be some fundamental rules that never change, for example the fact that something exists. You can't have areas of the universe in which the universe itself does note exist (I think). Frankly I don't believe the universe is infinite, occam's razor says it's just very big. Last month there was a report about someone finding a pattern in galaxies that would suggest the universe is much smaller than we thought but light wraps around making it appear infinite... the theory was discarded very soon after more experiments were carried out, but it reminded me of that star trek episode.. state the nature of the universe - the universe is a hollow sphere 12 km in diameter ... or something. Infinity is just our perception of things very big... something that originates from nothingness and expands has very little chances of becoming infinite in finite time. mirai++ I think two things are being confused. First, the laws of physics, second, the laws of probability. A gas particle follow physical rules (movement, bumping, thermal vibrations) and lots of gas particles together follow probability rules (low probability of people suffocating in rooms). The problem is that all the laws of physics have been found observing the world around us in an experimental way. But all the outcomes of an experiment are probabilistc and we know the low of physics only with a certain error. So the paradox in the laws of probability is a paradox in laws of physics too. The whole physics is probabilistic. -- Joao Pedro Leao ::: [EMAIL PROTECTED] Harvard-Smithsonian Center for Astrophysics 1815 Massachussetts Av. , Cambridge MA 02140 Work Phone: (617)-496-7990 extension 124 Cell-Phone: (617)-817-1800 -- All generalizations are abusive (specially this one!) ---
Re: Quantum accident survivor
Yes, this is Quantum Immortality in a nutshell. If the MWI is correct, it is impossible to die from a subjective point of view. Hooray! Yes but there can be no communication from one possible world to another (thus no cross-world awareness), because, think about it, if I could communicate with another world, then the other world would by definition be in my world (where I define my world as all parts of the universe that I can influence with a lightspeed communication), so it would just be some other part of my world. Oops. The bottom line is that if there are other possible worlds existing, they can be of nothing other than theoretical interest to us. Damn. So try to avoid running into any creatures weilding large scythes or other sharp implements tonight. Eric
Re: Quantum accident survivor
You are quite right in one point, Hal: ...probably a lot of things!. But you should have written: Certainly a lot of things, each one with high probability. If you pick photons rather than, say, flying massive debris, you should in all honesty, include photons along all the spectrum including, of course, gamma rays, which will kill you not just now, but keep on killing softly you forever by blasting the nuclear structure of your atoms and persuading them to decay. You would conclude that if you survive the blast, you would, with the help of QM be able to calculate precisely how dead you already are! So there is a branching event for you: if you survive a nuclear blast, how sure could you be that you really survived? Laurie Anderson was fond of saying: What kills you is not the bullett, its the hole!. -Joao Leao Hal Finney wrote: David Kwinter writes: The concept of what makes a real quantum branch irks me. Surely a man standing beside a nuclear explosion will never survive. Not necessarily. What exactly kills a man standing by a nuclear explosion? Well, probably a lot of things, but let's think about the radiant heat energy released by the blast. This heat is carried by photons, each of which is emitted by some atom in the nuclear device. When an atom emits a photon, the direction of its emission is random. With the large numbers of atoms and photons involved, the emission is, on average, uniform in all directions, which is what we expect. But each individual emission is a quantum effect, and there is a chance that all of the atoms in the nuclear device could happen to emit their photons in a different direction than towards the man. In that case he would not experience the heat energy from the device and would not be killed by it. I think similar arguments are possible for the radiation and all other sources of destruction coming from the nuclear explosion. So a man standing beside such an explosion could in fact survive. It's also possible that the photons and other radiation from the device might happen to pass through the man's body without being absorbed. Each photon has a certain probability of being absorbed, per unit distance that it travels through biological tissue. And each absorption event is governed by quantum randomness. Therefore there is a nonzero chance that a photon could pass entirely through the man's body, and in fact that all of the photons could do so. In effect the man might just happen to become transparent at the precise instant necessary to survive the blast. Probably there are other bizarre quantum coincidences which could occur to let him survive as well. Hal Finney -- Joao Pedro Leao ::: [EMAIL PROTECTED] Harvard-Smithsonian Center for Astrophysics 1815 Massachussetts Av. , Cambridge MA 02140 Work Phone: (617)-496-7990 extension 124 Cell-Phone: (617)-817-1800 -- All generalizations are abusive (specially this one!) ---
Re: Quantum accident survivor
OK, what about heat? Heat fills low pressure areas uniformly so there could be no bubble of non-vaporizing heat for the scientist to live in. Isn't the heat an absolute killer? On Friday, October 31, 2003, at 10:55 AM, Hal Finney wrote: David Kwinter writes: The concept of what makes a real quantum branch irks me. Surely a man standing beside a nuclear explosion will never survive. Not necessarily. What exactly kills a man standing by a nuclear explosion? Well, probably a lot of things, but let's think about the radiant heat energy released by the blast. This heat is carried by photons, each of which is emitted by some atom in the nuclear device. When an atom emits a photon, the direction of its emission is random. With the large numbers of atoms and photons involved, the emission is, on average, uniform in all directions, which is what we expect. But each individual emission is a quantum effect, and there is a chance that all of the atoms in the nuclear device could happen to emit their photons in a different direction than towards the man. In that case he would not experience the heat energy from the device and would not be killed by it. I think similar arguments are possible for the radiation and all other sources of destruction coming from the nuclear explosion. So a man standing beside such an explosion could in fact survive. It's also possible that the photons and other radiation from the device might happen to pass through the man's body without being absorbed. Each photon has a certain probability of being absorbed, per unit distance that it travels through biological tissue. And each absorption event is governed by quantum randomness. Therefore there is a nonzero chance that a photon could pass entirely through the man's body, and in fact that all of the photons could do so. In effect the man might just happen to become transparent at the precise instant necessary to survive the blast. Probably there are other bizarre quantum coincidences which could occur to let him survive as well. Hal Finney David Kwinter
Re: Quantum accident survivor
Joao Leao, [EMAIL PROTECTED], writes: You are quite right in one point, Hal: ...probably a lot of things!. But you should have written: Certainly a lot of things, each one with high probability. If you pick photons rather than, say, flying massive debris, you should in all honesty, include photons along all the spectrum including, of course, gamma rays, which will kill you not just now, but keep on killing softly you forever by blasting the nuclear structure of your atoms and persuading them to decay. You would conclude that if you survive the blast, you would, with the help of QM be able to calculate precisely how dead you already are! I'm not sure if you are joking here; do you agree that even gamma ray photons may happen to miss your body due to the quantum randomness in their emission and absorption events? So there is a branching event for you: if you survive a nuclear blast, how sure could you be that you really survived? Which brings up another possibility, which is that your body could spontaneously re-assemble from atoms in the environment even if it were temporarily destroyed. In that case you might have genuine uncertainty as to whether you really survived, depending on your views of personal identity and survival. Hal
