On 29 Apr 2017 2:33 a.m., "Bruce Kellett" <[email protected]> wrote:
On 29/04/2017 1:18 am, Bruno Marchal wrote: > On 27 Apr 2017, at 23:22, Brent Meeker wrote: > > The absurdity, if I've understood this, is that idea of physical >> substitution leads to a conclusion that nothing physical is needed. >> > > The absurdity is that the first person experience in physics has to be a > sum on all computations (to be short). > This might cause some problems for the SAN04 argument. The "Yes, doctor" assumption says that if my brain is replaced by a functionally correct digital device (at the appropriate substitution level), then I would not be aware of any experiential change. But if my first person experience is the sum on all computations that pass through my conscious state, then no digital computer could ever be a "sum on an infinity of computations", so my conscious state could not be reproduced in this way. In fact, as has been said, the sum on all computations is not Turing emulable. Thus my conscious state is not Turing emulable, and the "Yes, doctor" scenario fails -- we would have to say "No" to the doctor. The second problem with the idea that the first person experience has to be the sum on all computations, is that this renders duplication of persons impossible. If you duplicate the computation(s) that make up a first person experience, you have simply added some more computations to that experience and the sum over *all* computations is unchanged. Thus there is still only one first person experience, and the attempted duplication fails. So, if the "Yes, doctor" assumption, and the subsequent duplication scenarios, lead to the conclusion that the first person experience is a sum on all computations, the argument is self-contradictory: the conclusion contradicts the input assumptions and the argument is incoherent. Well, you've certainly​ found a way to make it appear incoherent. But here's another way to look at the matter that may help. The multiplicity of machines implied by the UD are in principle objectively distinguishable so in that sense there is no "sum". However let's consider the situation vis a vis identical machine states, any of which might comprise, by assumption, my present subjective state. Now there is no possibility of an objective mapping from the subjective state to a single machine in the multiplicity. As Bruno puts it, if I am indeed a machine, I can't know which one. In that sense my present subjective state could be considered a "sum" over those identical machine states. So if my brain were then to be replaced by a functionally identical prosthesis there would be no change in that "sum" and so my experience, again by assumption, would be unchanged. Ditto for duplication of persons. The key point here is to distinguish between the third-person (computational) and first person (perceptual) situations​. Of course, when one looks beyond any given present state, divergence of subsequent machine state continuations would then in principle render the associated personal histories both objectively and subjectively distinguishable. Hope this helps. David Bruce So even if a physical universe exists, it *cannot* have any influence on my > prediction. Physics lose *all* its prediction power. Computationalism saves > physics, we should say, but makes it more modest when wandering on > metaphysics. > -- 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 https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout. -- 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 https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
