On Wed, May 06, 2015 at 01:32:41PM -0400, John Clark wrote: > > > > Russell Standish wrote: > > http://www.hpcoders.com.au/blog/wp-content/uploads/2014/08/mgaRevisted.pdf > > > The Movie Graph Argument seeks to parlay this into an absurdity, where > > there is no active physical difference between a conscious computation, and > > the mindless replaying of a recording. > > > It seems to me that the first thing to do when starting a Reductio ad > absurdum proof is to make sure the conclusion really is absurd, and this > one isn't >
A better aim is proof by contradiction. > If 2 identical computers are running the same AI program computationalism > says there is only one conscious being. If one of the 2 computers is > destroyed computationalism says there is no subjective difference and > nobody died. Time is only meaningful in its relationship to something else > so if the computer is stopped for a billion years and then started up again > there is no subjective difference. If the computer is reset and the same AI > program is run again computationalism says there is no subjective > difference. If the exact same program is rerun on the computer a trillion > times computationalism says there is still only one conscious experience, > that is to say subjectively things would be exactly the same if it had been > run only one time. When a recording of consciousness is played back does > the consciousness exist during the playback or just when the computer was > actually making calculations? If computationalism is true, and I think it > is, then the answer to that question doesn't make any subjective difference > whatsoever. > Exactly. That was one of my points. > What about intelligence, when somebody in the 21th century reads what > Newton accomplished did the intelligence occur in the 17th century or the > 21th? Operationally it makes no difference. Does this mean that > consciousness and intelligence exists outside the normal bounds of space > and time? In a way it sorta does which is why I'm reluctant to say physics > is definitely more fundamental than mathematics; but in another way it > sorta doesn't because the entire argument hinges on the existence of a > computer that operates according to the laws of physics, which is why I'm > reluctant to say mathematics is definitely more fundamental than physics. I > just don't know. . > > > > > One of the consequences of the universal dovetailer argument is that > > you cannot tell which computer program is you. > > Well that sure didn't take long, already on page 1 we run into one of those > damn ambiguous personal pronouns. And in your scenario there is only one > serial program and it is running the entire multiverse so it would be very > easy indeed to say what program is "you" assuming that personal pronoun > means anything. > That doesn't cause any problem. One can just as easily say a person cannot know which program is instantiating that person. (Person as in the sense of Parfit, of course). > > > For every program that instantiates your current conscious state, there > > are an infinite number of possible continuations of that program, > > corresponding to different possible futures. This leads to an irreduciable > > indeterminism > > There is nothing new in this, Turing proved 80 years ago that in general > the behavior of even very simple programs can not be predicted, if you want > to know what it will do all you can do is watch. This is not the same result as the halting theorem, to which you are presumably referring. > And Og the caveman > discovered that people don't always know what they will see next so I see > no reason for a new homemade acronym like "FPI". > Because Og the caveman is more likely to be describing the results of a chaotic system rather than FPI. > > > even an omniscient god cannot know what you will experience next. > > Because even a omniscient god cannot answer a question that isn’t really a > question but is gibberish. > Why is what I'll experience next a gibberish question? I'd like to know before actually experiencing it! > > > the Church-Turing thesis implies that it doesn’t matter what > > physical computer the dovetailer is run on. > > I'm glad you said "physical", the dovetailer could be made many different > ways but however its made as far as we know it must be constructed of > matter and it must operate according to the laws of physics. > > > >The wrinkle is to suppose that the universe doesn’t have sufficient > > resources to run a universal dovetailer. Whilst a universal dovetailer can > > be coded and run on the physical computers we have today, in practice only > > a short initial portion of the UD can be run. What if the universe goes > > into a heat death before any conscious program is started? To distinguish > > between these cases, Marchal calls a universe capable of running a > > universal dovetailer fully a robust universe. > > > So at the very start you've got to assume the existence of a physical > universe and a very special type of physical universe. Does this mean > physics is more fundamental than mathematics? > Not really. It just makes the arguments easier to make at that point. > > we can, for the purposes of this argument, consider robust universes to > > be ones that can run enough of the universal dovetailer for > > programs instantiating all possible human experiences of consciousnesses > > within a human life time be executed. This is still an immense universe, > > but no longer an infinite one. > > > You said the dovetailer "leads to an irreduciable indeterminism", but if > the machine is finite then a faster but still finite computer could predict > what the dovetailer will do; it still could not of course predict what > "you" will see next because in this context that personal pronoun has no > meaning, it would be like asking what klogknee will fluxanate next. > I disagree. What I experience next has a quite specific meaning, and I'll find out by waiting around long enough. What you will experience next I can only give a probabilistic answer to, but still has a precise meaning to you. > > Since all our possibe experiences will be instantiated, and observed, > > our phenomenal physics depends only on the properties of the universal > > machine, not on any underlying physical sustrate. > > > But there is one physical substrate that is still of critical importance, > the substrate out of which your dovetailer machine is built because nobody > knows how to make a Turing Machine or a computer or how to make one single > calculation without using matter that operates according to the laws of > physics. Maybe there is some other way to do it but if there is nobody > knows what it is. > IMHO, one can never know what it is made out of. Our universe could be running on a range of different hardware, and we'd be none the wiser. It could be Bruno's Platonic integers for all we could tell. > > it is observed that different brain states invariably correspond to > > different conscious experiences. > > > And different brain states lead to different physical behavior. > > > > Now consider the scenario of a class of school children, one of whom > > is named Alice, and another Bob. Does Alice’s consciousness supervene on > > the class? Well, yes, as we observe that any change in Alice’s > > consciousness must correspond to a physical change in the classroom, > > concentrated in Alice’s brain. > > > Or to say the same thing more simply, the Turing Test (a behavioral test) > works for both intelligence and consciousness. > Well the Turning test usually doesn't involve opening up people's heads and scanning the neuronal states, but if it did then you'd be right. > > But we can ask a slight different question — does consciousness supervene > > on the class. In this case, we’d have to answer no, because both Alice’s > > conscious states and Bob’s, not to mention the teacher’s and other students > > are all present in the class. A difference in conscious state does not > > correspond to a physical difference. > > > I have no idea what you're talking about here, if one person effects the > class the other class members will effect it too. > That is not what I'm saying. If I experience being Alice within the class, then I'm experiencing something different to the case if I'm experiencing being Bob in the class at the exact same moment. Two different conscious experiences, exact same physical state. > > We can express the same conundrum using the speech case, exploiting the > > so-called “cocktail party” effect. Alice says “hello”, and Bob says > > “hi” simultaneously — but which word we hear depends on who we’re actively > > listening to. > > And the programming of the dovetailer determines who we're actively > listening to. I really don't see what you're drivin at. > > > > The words no longer supervene on the air molecules, but on the state of > > the listener. > > > You've lost me. > The air molecules are in the same physical state. Neverthless in one case, the listener hears “hello” in a feminine voice, and in the other case "hi" in a masculine voice. > > if program A executes the ”or” instruction on registers x and y, and B > > executes the ”and” instruction. If it so happens that both x and y both > > contain the same value (both true or both false), then the resultant > > machine state is identical with each program. Yet the two programs are > > quite different, as if the two registers had different values, the > > resulting machine state would be quite different. We call this “if it had > > been different” a counterfactual. > > > If quantum mechanics has taught us anything it's that counterfactuals are a > intellectual dead end, you can't make a measurement you didn't make. You > can choose to measure the position of a particle with as much accuracy as > you want but if you do you will have little idea what its momentum would be > and it would be pointless to speculate what the momentum value would have > been if you had chosen to measure that instead of position. > The MWI reifies all counterfactuals. So QM actually seems to be saying the opposite. > > In this case, programs A and B are not counterfactually > > equivalent. It seems plausible that counterfactual inequivalence is needed > > as part of the definition of what could differ between computations > > supporting different conscious experiences. > > > That doesn't seem the least bit plausible to me, as long as the inputs are > both true (or both false) then I don't see how on earth it could make any > difference, the "and" instruction produces the same result as the "or" > instruction and the machine is in the identical state. Therefore if > computationalism is true then your above statement is more than just > implausible it is flat out wrong. > In the MWI, there a big physical difference. Just not from our viewpoint. Computational supervenience only implies supervenience of conscious on a class of programs. Since two logically inequivalent programs can result in the same sequence of classical physical states, there is a distinction between computational supervenience and physical supervenience. Of course, in the MWI, there is no such difference, which is one of my main critiques of Maudlin's thought experiment. > > if counterfactual situations are physically realised somewhere in > > the multiverse, then [...] > > > Then if things were different then things would be different. If one input > were 0 and the other 1 then there would be a difference between that > universe and the universe where both inputs were 0 or both 1 and so the > universe would split and the consciousness of the AI program would be > different too so it also would split. > > > This is supported by the intuition that a mere playback of a recording > > of a conscious machine (eg reanimating a dead brain by passing recorded EEG > > sgnals through the neurons) is not sufficient to instantiate > > a consciousness. > > > That isn't my intuition! Audio and video can be recorded and I see no > reason why in theory consciousness couldn't be recorded too, as I explained > above if computationalism is true things like that must be possible, after > all... that's what computationalism means. > Nor mine. For any sufficiently detailed recording of someone's mind, I don't think can intuitively say that the counterfactually incorrect version is not conscious. I'm glad you agree. > > > > The idea is that the conscious computation is implemented as a graph (or > > network) of stateful objects (eg abstract neurons) embedded in a glass > > plate. This allows a movie camera to record a movie of the operation of the > > artificial brain. Then by parts, he severs some of the > > network links between neurons, but by projecting the movie back onto the > > network, is able to excite those neurons as though they were still > > connected. > > > But the neurons still are connected just in a more roundabout way, the > excitation signal from neuron X is recorded on film and then sent to neuron > Y my means of the projector. I really don't see the point of this thought > experiment. It is meant to be some sort of intuition pump, just like Searle's Chinese Room. And it should be answered the same way - the complexities involved in actually doing the experiment really mean all bets are off - the intuition pump runs dry. > > > > > The requirement that the computations be counterfactually correct > > means two distinct conscious experiences may produce the same sequence of > > machine states, but they must differ in their behaviour for some > > counterfactual machine state. > > > That certainly isn't computationalism and it isn't science either because > science deals in the experiments you made not the experiments you didn't > make. > All computational supervenience gets you is that two counterfactually equivalent programs will generate the same conscious state. All bets are off with counterfactually inequivalent programs that nevertheless result in the same physical state. For that you additionally need physical supervenience. The whole business of the recording is how can that physical apparatus replaying the conscious moment actually be conscious, when it is not aware of the environment. As far as computationalism is concerned, the experienced moment has already been experienced, at some previous time and place (there and then). Replaying the recording makes no difference whatsoever. Yet the same sequence of physical states takes place, so in some sense by physical supervenience a new conscious moment is created. I don't think it can be, and I don't think this is what physical supervenience can actually mean. -- ---------------------------------------------------------------------------- Prof Russell Standish Phone 0425 253119 (mobile) Principal, High Performance Coders Visiting Professor of Mathematics [email protected] University of New South Wales http://www.hpcoders.com.au ---------------------------------------------------------------------------- -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
