tag:blogger.com,1999:blog-6642011.post109935892644360135..comments2023-10-29T10:32:36.914-04:00Comments on Philosophy, et cetera: Are Brains Computers?Richard Y Chappellhttp://www.blogger.com/profile/16725218276285291235noreply@blogger.comBlogger9125tag:blogger.com,1999:blog-6642011.post-43009770479425125572012-01-23T15:50:42.992-05:002012-01-23T15:50:42.992-05:00It is most useful to use idealized concepts like T...It is most useful to use idealized concepts like Turing machines and ideal minds. The ideal mind concept was hinted at by "an uber genius who had a million years to solve the problem" but it should really be a person with an infinite IQ, and maximized {whatever it is that humans have} as well as infinite time etc. Then compare that to a Turing machine. Von Neumon computers versus neural nets would be identical in this idealized sense if we are talking about neural nets simulated on Turing machines. If we mean neural nets with infinite precision, then we get into hypecomputation which cannot be fully simulated on a computer.<br /><br />Many hypercompuation (beyond Turing machines) devices have been formulated theoretically, but they cannot be built in the real world. People are "built" in the real world, but i imagine that if people have a way to get outside of themselves even in the most subtle way to get answers for things that they cannot compute (true intuition), then that may explain why we are non-computational.<br /><br />If, however, we are Turing machines, then the vast transfinite infinity of problems unsolvable by machines would apply to us as well...of which only an infinitessmal of probelms are deciable to us and the same would be true of humans. <br /><br />I do not buy arguments that humans cannot solve undecidable problems because we would need an algorithm to do it and that is by definition impossible. We clearly have the ability to perform semantic reasoning and that is, in an ideal sense, uncomputable...so the question becomes: can non-algorithmic language (for example the langauge we are all using to make our cases) have precise meaning to humans? <br /><br />This gets into berry's paradox: "A phrase under 1000 characters that denotes the smallest number, k, that cannot be denoted with 1000 characters or less." denotes such a phrase even when we are limited to a finite combination of symbols because the process of denoting is non-algorithmic. Is such a word as "denote" merely ambiguous or is it truly uncomputable? The same question applies to "meaning" and understanding. I am absolutely convinced that idealized minds cannot be simulated by Turing machines...what is not so clear is if physical humans have such abilities. But perhaps humans are to idealized minds what physical computers are to Turing machines.<br /><br />-Gary Geck---------https://www.blogger.com/profile/16701799527970122680noreply@blogger.comtag:blogger.com,1999:blog-6642011.post-1125250039077655712005-08-28T13:27:00.000-04:002005-08-28T13:27:00.000-04:00a more efficient model of modern computers would b...a more efficient model of modern computers would be an abacus machine anywayAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6642011.post-1099607978159192212004-11-04T17:39:00.000-05:002004-11-04T17:39:00.000-05:00Daniel
We can only speculate. The problem is we h...Daniel<br />We can only speculate. The problem is we have to understand both the brain and the hypothetical AI before we can address the problem theoretically. Obviously playing chess (the way a computer plays) is a highly mechanical activity. Human chess players use quite different strategies which probably include semi-intuitive rules for evaluating a game position. Top chess players have been shown to have exceptional ability to remember a chess game position when shown it briefly but do no better than the general population at remembering positions where the pieces are placed randomly. I included it as a cautionary tale. A lot of knowledgeable experts recognised that the human chess game is much more complex than finite depth minimaxing and therefore concluded that computers (at least the conventional computer chess program) would not be able to play top-level chess. The premise that human and computer chess are different was (probably) correct butthe conclusion that computers could not play at Grand Master level was wrong. The "dumb but reliable" searching computer algorithm outperforms the much more elegant ut error-prone human "art of chess".<br /><br />As far as emotions, desires, evaluation sensibilities are concerned we can certainly postulate that they can run on the right sort of computer architecture. If we accept that the human brain IS a massively parallel network then the fact that they exist in the human brain proves that they can run on such networks. The only alternative is to invoke some sort of vitalism. Of course, the "real" nature of emotions, etc may be quite different to what they think they are.<br /><br />Richard I don't know any formal stuff about non-Turing machines but assume that the essential feature would be that state transitions are not (all) strictly determinable. This can happen with networks of computers with unsynchronised clocks and is more or less assumed in parallel systems even with synchronised clocks. Typically subtasks are assigned to processing units as they become available and we assume that the exact time taken by each subtaskis not known in advance. A computer program running on a single PC would also be a non-Turing machine if it responds to an analog input such as a temperature probe.  <br /><br /><A></A><A></A>Posted by<A><B> </B></A><A HREF="http://www.blogger.com/r?http%3A%2F%2Fgreyshade.blogspot.com" TITLE="sos at actrix dot gen dot nz">Greyshade</A>Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6642011.post-1099595858923191902004-11-04T14:17:00.000-05:002004-11-04T14:17:00.000-05:00Greyshade - A couple thoughts...First, are not emo...Greyshade - A couple thoughts...First, are not emotions, desires, evaluative sensibilities, etc simply *different kinds of things* from anything that would go on in a massive parallel network running a self-modifying, "learning" program? My point is just that (e.g.) learning (or being taught) how to play chess seems to be very different *kind of thing* from having affective and evaluative conscious experience. Second, how would we *test* other human beings? Is there a (realistic) chance we will be able to know what a person *believes* and is phenomenologically experiencing?<br /><br />I would be very interested in such developments. Some links or article/book recommendations would be greatly appreciated. <br /><br /><A></A><A></A>Posted by<A><B> </B></A>DanielAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6642011.post-1099594520545584682004-11-04T13:55:00.000-05:002004-11-04T13:55:00.000-05:00Richard - In my post I was assuming that what you ...Richard - In my post I was assuming that what you meant by 'computer' was something like an "abstract symbol manipulator" and not my PC :) However, it seems that my conscious experience is not *merely* a matter of symbol manipulation - much of it is, I agree, but it's hard to see how *desires* and *emotions* fit the category. Though affections and evaluative states are (often) intentional and are "directed" at an object (or symbol), they are not merely such. Obviously I need (and want) to study some cognitive science and AI work, and this may help alter my deeply embedded "intuitions" about conscious experience. But then again, does the cognitive scientist/philosopher really know more about what it is *like* to be a human being and have conscious experience than I do? ...I guess my affinity with some of Chalmers' work is becoming obvious :) <br /><br /><A></A><A></A>Posted by<A><B> </B></A>DanielAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6642011.post-1099550804333267732004-11-04T01:46:00.000-05:002004-11-04T01:46:00.000-05:00Daniel - Note that by 'computer' I really just mea...Daniel - Note that by 'computer' I really just mean an abstract symbol-manipulator. The 'Von Neumann' computers we're used to are just one form of this, as Greyshade notes, and are very different from the brain. So that is not what I meant by 'computer'.<br /><br />Taking computation to mean the manipulation of representations (i.e. symbols), it does seem to me that this is how our minds must work. We represent the world through our beliefs, desires, and other mental states, and these interact through various computations. I'm not sure how else it could be. (Though as I said, I would like to hear about the alternatives.)<br /><br />As for consciousness, I'll be posting a bit on Dennett's views of that over the next few days. In short, he basically thinks it's a sort of "virtual machine", i.e. special <I>software</I> which is run on our neural hardware (brain). No existing computers have software anything like it, but it's not in principle impossible for them to do so.<br /><br />Greyshade - I agree that it's not something we can judge objectively, but I don't really have a problem with judging AI's from our biased human standpoint. 'Intelligence', 'emotion', etc. are human concepts, so I'm happy to let us decide where they apply. If a robot behaves in such a way that's it strikes us as useful and appropriate to attribute these abilities to them, then we should do so. If not, then we shouldn't . It's less than ideal, I suppose, but I'm not sure what else we can do here.<br /><br />P.S. Are non-Turing machines still 'computers' (in the symbol-manipulation sense), or are they something else? (I really don't know anything much about them.) <br /><br /><A></A><A></A>Posted by<A><B> </B></A>RichardAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6642011.post-1099541856905285542004-11-03T23:17:00.000-05:002004-11-03T23:17:00.000-05:00A "Von Neumann Architecture" computer running a fi...A "Von Neumann Architecture" computer running a fixed program is going to be quite different to a massively parallel network running a self-modifying, learning AI program designed to simulate a human brain. The problem with the question of whether such an AI can exhibit "real" intelligence, emotions, self-awareness, etc is defining them and coming up with experiments by which they can be tested. We might, for instance, have a contest between a human an an AI to compose a poem or a piece of music on the subject "Who am I?" but would we judge the results on the basis of human or AI response to them. It would seem to me that a fair appraisal would be possible only if a hypothetical silicon-chemistried (or whatever) space alien was available as a judge. <br /><br />For a long time we thought that the "art" of playing grand-master level chess would be beyond any computer because of the limited search depth. It turns out that computer programs can beat human grand masters rather easily. This is not because they play grand master chess but because they play a simpler erro-free game and human chess players (even at the highest levels) make far more errors than we realised but get away most of them because their opponents don't spot the error either - unless the opponent is a computer. <br /><br /><A></A><A></A>Posted by<A><B> </B></A><A HREF="http://www.blogger.com/r?http%3A%2F%2Fgreyshade.blogspot.com" TITLE="sos at actrix dot gen dot nz">Greyshade</A>Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6642011.post-1099533529651670082004-11-03T20:58:00.000-05:002004-11-03T20:58:00.000-05:00I took a philosophy of mind course last year and o...I took a philosophy of mind course last year and one thing that always struck me as odd was the claim that "the brain" is structurally/functionally akin to a computer. Now, I realize there are obvious parallels between the two, but I also think there are obvious (and important) dissimilarities. For example, if our 'mental life' (i.e. conscious and unconscious experience) is taken to be either identical to or supervenient upon 'the brain' (as many would suggest), I find it striking that even the most sophisticated computers would seem to lack the affective/evaluative nature of our mental awareness. This is obviously no minor difference. How would a proponent of the view that brains = computers try to account for it? <br /><br /><A></A><A></A>Posted by<A><B> </B></A>DanielAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6642011.post-1099444245213919842004-11-02T20:10:00.000-05:002004-11-02T20:10:00.000-05:00The human brain is a mechanistic "computer" but a ...The human brain is a mechanistic "computer" but a complex "neural net". If it is fully deterministic then it must have a complete "table" and by definition is a Turing machine. If there is some level of indeterministic behaviour it is most unlikely the brain would "halt" (it will presumably branch "randomly" to one of several possible new states) and this would mean it wasn't a Turing Machine.<br /><br />If the human brain can solve the halting problem then it must be a non-Turing machine and the halting problem is obviously computable by such a non-Turing machine. On the other hand the halting problem may be non-computable by any finite machine and the human brain may be a fully deterministic Turing machine. Stating that there is no reason to believe that the human brain cannot solve the halting problem is a long way from proving that it CAN.  <br /><br /><A></A><A></A>Posted by<A><B> </B></A><A HREF="http://www.blogger.com/r?greyshade.blogspot.com" TITLE="sos at actrix dot gen dot nz">Greyshade</A>Anonymousnoreply@blogger.com