On 3 October 2013 10:33, meekerdb <meeke...@verizon.net> wrote: > On 10/2/2013 5:15 PM, Stathis Papaioannou wrote: >> >> On 1 October 2013 23:31, Pierz <pier...@gmail.com> wrote: >>> >>> Maybe. It would be a lot more profound if we definitely *could* reproduce >>> the brain's behaviour. The devil is in the detail as they say. But a >>> challenge to Chalmer's position has occurred to me. It seems to me that >>> Bruno has convincingly argued that *if* comp holds, then consciousness >>> supervenes on the computation, not on the physical matter. >> >> When I say "comp holds" I mean in the first instance that my physical >> brain could be replaced with an appropriate computer and I would still >> be me. But this assumption leads to the conclusion that the computer >> is not actually needed, just the computation as platonic object. > > > But what if you were just slightly different or different only in some rare > circumstances (like being in an MRI), which seems very likely?
If the replacement were slightly different then under particular circumstances the consciousness would be different. It's like any other prosthesis that might function well in most situations but fail if pushed beyond a certain limit. >> So if >> it's true that my brain could be replaced with a physical computer >> then my brain and the computer were not physical in a fundamental >> sense in the first place! > > > But this depends on the MGA or Olympia argument, which find suspect. Yes, but the point I wanted to make was that the case for functionalism is not destroyed even if this argument is valid. >> While this is circular-sounding I don't >> think that it's actually contradictory. It is not a necessary premise >> of Chalmer's argument (or indeed, for most scientific arguments) that >> there be a fundamental physical reality. >> >> As for reproducing the brain's behaviour, it comes down to whether >> brain physics is computable. It probably *is* computable, since we >> have not found evidence of non-computable physics of which I am aware. > > > Suppose it was not Turing computable, but was computable in some other sense > (e.g. hypercomputable). Aren't you just setting up a tautology in which > whatever the brain does, whatever the universe does, we'll call it > X-computable. Already we have one good model of the universe, Copenhagen > QM, that says it's not Turing computable. I think the usual meaning of "computable" is Turing computable. >> If it is not, then computationalism is false. But even if >> computationalism is false, Chalmer's argument still shows that >> *functionalism* is true. Computationalism is a subset of >> functionalism. >> >>> But functionalism suggests that what counts is the output, not the manner >>> in which it as arrived at. That is to say, the brain or whatever neural >>> subunit or computer is doing the processing is a black box. You input >>> something and then read the output, but the intervening steps don't matter. >>> Consider what this might mean in terms of a brain. Let's say a vastly >>> advanced alien species comes to earth. It looks at our puny little brains >>> and decides to make one to fool us. This constructed person/brain receives >>> normal conversational input and outputs conversation that it knows will >>> perfectly mimic a human being. But in fact the computer doing this >>> processing is vastly superior to the human brain. It's like a modern PC >>> emulating a TRS-80, except much more so. When it computes/thinks up a >>> response, it draws on a vast amount of knowledge, intelligence and >>> creativity and accesses qualia undreamed of by a human. Yet its response >>> will completely fool any normal human and will pass Turing tests till the >>> cows come home. What this thought experiment shows is that, while >>> half-qualia may be absurd, it most certainly is possible to reproduce the >>> outputs of a brain without replicating its qualia. It might have completely >>> different qualia, just as a very good actor's emotions can't be >>> distinguished from the real thing, even though his or her internal >>> experience is quite different. And if qualia can be quite different even >>> though the functional outputs are the same, this does seem to leave >>> functionalism in something of a quandary. All we can say is that there must >>> be some kind of qualia occurring, rather a different result from what >>> Chalmers is claiming. When we extend this type of scenario to artificial >>> neurons or partial brain prostheses as in Chamer's paper, we quickly run up >>> against perplexing problems. Imagine the advanced alien provides these >>> prostheses. It takes the same inputs and generates the same correct outputs, >>> but it processes those inputs within a much vaster, more complex system. >>> Does the brain utilizing this advanced prosthesis experience a kind of >>> expanded consciousness because of this, without that difference being >>> detectable? Or do the qualia remain somehow confined to the prosthesis >>> (whatever that means)? These crazy quandaries suggest to me that basically, >>> we don't know shit. >> >> Essentially, I think that if the alien computer reproduces human >> behaviour then it will also reproduce human qualia. Start with a >> prosthesis that replaces 1% of the brain. If it has different qualia >> despite copying the original neurons' I/O behaviour then very quickly >> the system will deteriorate: the brain's owner will notice that the >> qualia are different and behave differently > > > I don't see how you can be sure of that. How will he compare his qualia of > red now with his qualia of red before? And why would small differences > imply "the system will quickly deteriorate". Suppose he became color blind - > which he could realize - Color blind people are still conscious. It's not that he would lose consciousness, it's that there would be a change in consciousness which would lead to a change in behaviour. A person who became colourblind would change his behaviour by failing a colour test or by saying in response to being asked if he felt different, "Yes, colours look different when the prosthesis goes online". If the colourblindness causes no objective or subjective change then it isn't really a change at all. It could be that in ordinary life my red and green qualia are reversed every Wednesday, but I don't notice and I don't care, so I won't notice and I won't care if the same thing happens with a brain prosthesis. >> , which is impossible if >> the original assumption about copying the original neurons' I/O >> behaviour is true. > > > See above point about approximation and circumstance. The prosthesis will be specified to work in particular circumstances. >> The same is the case if the prosthesis replaces 99% >> of the neurons - the 1% remaining neurons would notice that the qualia >> were different and deviate from normal behaviour, and the same would >> be the case if only one of the original neurons were present. > > > You seem to be agreeing with Craig that each neuron alone is conscious. The experiment relates to replacement of neurons which play some part in consciousness. The 1% remaining neurons are part of a system which will notice that the qualia are different. -- Stathis Papaioannou -- 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/groups/opt_out.
