On Wed, Oct 14, 2015 at 1:17 AM, Bruce Kellett <bhkell...@optusnet.com.au> wrote:
> On 14/10/2015 4:45 pm, Jason Resch wrote: > > Cochlear implants and artificial retinas give evidence toward multiple > realizability, and therefore, against mind-brain identity theory. They show > that it is functional equivalence, rather than material/compositional > equivalence that matters. Since computers can realize any finite function, > then assuming there are no necessary infinities within the brain, computers > can realize any functional state the brain is able to realize. For > physicalism to be correct, you have to believe either that functional > states are irrelevant to consciousness, or that physics can instantiate > functional states which Turing machines cannot. > > > That is simply false. > > Well that explains it. > > Again it's not clear what you mean by computationalism. Bruce can speak >> for himself, but I think he agrees that strong AI is possible. >> >> > Strong AI implies consciousness is substrate independent. But I thought > Bruce argued against consciousness being derivable from mathematical > computations, which would mean consciousness is substrate dependent: that > it depends on physically implemented Turing machines. > > > I certainly argued that consciousness could not be sustained on platonic > computations in arithmetic. But that was because I do not accept that such > things exist. > What evidence have you seen that led you to this conclusion? > In mathematics you have descriptions of Turing machines and descriptions > of computations, but no live machines or computations. > There are both. > Substrate independence simply means that you can replace all or part of > the human brain with computer-based equivalents. In other words, strong AI. > No need for platonia in order to say that consciousness is independent of > the substrate. > But if it is independent of substrate, and if computations exist platonically, then those platonic computations are equally capable of instantiating consciousness. > > > > > >> >> Why? Arithmetic is system of propositions. Whether it is real or not >> has no effect on Church-Turing. >> > > Then you should be equally happy to have your brain implemented by "unreal > computations" as "real computations" :-) > > > Computations in platonia are 'unreal' -- they do not exist, so cannot > implement anything. > [image: Inline image 1] > > > and it's difficult to make sense of computationalism if you can no longer > define computation or computability. So if you accept computationalism, you > are implicitly accepting infinity and arithmetical realism. Given this, the > rest of Bruno's result is a logical proof, which is either correct or has > an error. > > > No, you missed the point that it is not a logical proof. It's an argument > from incredulity. > > "A Turing Machine either reaches a halting state or runs forever" > "A Turing Machine can emulate any other Turing machine" > "A Turing Machine has an unlimited tape" > > None of the above items are true for physical approximations of Turing > machines. If these basic principals of computer science are not true for > physical Turing machines, then what kind of Turing machines are they true > for? Is Computer Science founded on lies, or does it concern itself with a > recently-discovered mathematical object for which these statements are true? > > > The definition is of an ideal Turing machine. No such ideal machine > exists. Mathematical objects are idealizations: they do not exist. Any > realization of a mathematical objects is necessarily less than ideal. > > If you born in a universe with slightly different laws, you would say this universe is only abstract and doesn't exist. I think you are just biased by what is familiar to you. Jason -- 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 everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
