Path: utzoo!attcan!uunet!zephyr.ens.tek.com!uw-beaver!ubc-cs!alberta!aunro!aupair.cs.athabascau.ca!auk.cs.athabascau.ca!holt From: holt@auk.cs.athabascau.ca (Peter D Holt) Newsgroups: comp.ai.philosophy Subject: Re: Reasoning Paradigms Message-ID: Date: 15 Oct 90 18:29:03 GMT References: <3586@media-lab.MEDIA.MIT.EDU> <69347@lll-winken.LLNL.GOV> <3593@media-lab.MEDIA.MIT.EDU> <69377@lll-winken.LLNL.GOV> <11@tdatirv.UUCP> <27@tdatirv.UUCP> Sender: news@cs.athabascau.ca Lines: 52 sarima@tdatirv.UUCP (Stanley Friesen) writes: >I was operating on the assumption that NN's were originally concieved as >a sort of crude analog to the type of processing done by living things. >I also assumed that the limitations of current NN's are due to limitations >of technology and knowledge, not fundamental limitations of circuits. >It is true there are many unknowns in neurobiology, but I do not see that >there is any reason to believe that neurons do anything that is not at >least amenable to aproximation using electronics. Indeed, I suspect that >they do not even do anything that cannot be exactly duplicated. >But even more important, I suspect that the exact details of biological >neurobiology are irrelevant to making a general purpose responsive network >[such as NN's]. That is, the redundancy and intrinsic variability in neuron >response patterns make exact duplication unnecessary. In basic operation >a neuron appears to be a complex combinatorial circuit. It performs some >sorted of a generalized weighted 'sum' of an enormous number of inputs >(often several thousand), and distributes the resulting signal to a large >number destinations (again often in the thousands). The summation is >probably quite different than the simple arithmetic sum used by current NN's, >and the weighting and threshold functions are probably more complex than >we currently imagine, but this is just a matter of technology and knowledge, >not metaphysics. >-- >--------------- >uunet!tdatirv!sarima (Stanley Friesen) The above is a very acceptable opinion. However, I think previously you have mixed up your opinions with fact. Just because the above is your opinion, it does not provide scientific support the contention of your original posting that the human brain is an existence proof that neural nets can do anything people can do. Without defining neural net such a statement is vacuous. If you define neural nets as what the brain has of course you are correct. BUT we do not know how exactly how those function or more importantly how they support all of cognition so we do not know if we can simulate that support. If you define neural networks in anyway approximating what I have seen or read of current simulations (or their approximating logical extensions) I suspect that you are wrong. BUT I do not even have to prove that, by any current standards of science it is up to you to demonstrate that you are correct. Since you cannot do that this would seem to imply that if there are any "metaphysics" involved here it is that neural nets have become somewhat of a religion for you. I do not mean to imply that synthetic or simulated neural nets are not a very interesting technology, nor that they do not have endearing attributes not found not found in symbolic AI. Nor that they may successfully models some aspects of human perception and cognition, I just question the usefulness of making claims for neural nets that are unsubstantiable.