Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site sdcsvax.UUCP Path: utzoo!watmath!clyde!akgua!sdcsvax!davidson From: davidson@sdcsvax.UUCP (Greg Davidson) Newsgroups: net.ai,net.philosophy Subject: Re: New topic for discussion (long) Message-ID: <736@sdcsvax.UUCP> Date: Fri, 27-Apr-84 23:51:58 EDT Article-I.D.: sdcsvax.736 Posted: Fri Apr 27 23:51:58 1984 Date-Received: Sun, 29-Apr-84 07:19:11 EDT References: <119@eneevax.UUCP> Organization: EECS Dept. U.C. San Diego Lines: 168 This is a response to the submission by Phaedrus at the University of Maryland concerning speculations about the nature of conscious beings. I would like to take some of the points in his/her submission and treat them very skeptically. My personal bias is that the nature of conscious experience is still obscure, and that current theoretical attempts to deal with the issue are far off the mark. I recommend reading the book ``The Mind's Eye'' (Hofstadter & Dennett, eds.) for some marvelous thought experiments which (for me) debunk most current theories, including the one referred to by Phaedrus. The quoted passages which I am criticizing are excerpted from an article by J. R. Lucas entitled ``Minds, Machines, and Goedel'' which was excerpted in Hofstadter's Goedel, Escher, Bach and found there by Phaedrus. the concept of a conscious being is, implicitly, realized to be different from that of an unconscious object This statement begs the question. No rule is given to distinguish conscious and unconscious objects, nothing is said about the nature of either, and nothing indicates that consciousness is or is not a property of all or no objects. In saying that a conscious being knows something we are saying not only does he know it, but he knows that he knows it, and that he knows that he knows that he knows it, and so on .... First, I don't accept the claim that people possess this meta-knowlege more than a (small) finite number of levels deep at any time, nor do I accept that human beings frequently engage in such meta-awareness; just because human beings can pursue this abstraction process arbitrarily deeply (but they get lost fairly quickly, in practice), does not mean that there is any process or structure of infinite extent present. Second, such a recursive process is straightforward to simulate on a computer, or imbue an AI system with. I don't see any reason to regard such systems as being conscious, even though they do it better than we do (they don't have our short term memory limitations). we insist that a conscious being is a unity, and though we talk about parts of our mind, we do so only as a metaphor, and will not allow it to be taken literally. Well, this is hardly in accord with my experience. I often become aware of having been persuing parallel thought trains, but until they merge back together again, neither was particularly aware of the other. Marvin Minsky once said the same thing after a talk claiming that the conscious mind is inherently serial. Superficially, introspection may seem to show a unitary process, but more careful introspection dissolves this notion. The paradoxes of consciousness arise because a conscious being can be aware of itself, as well as of other things, and yet cannot really be construed as being divisible into parts. The word ``aware'' is an implicit reference to the unknown mechanism of consciousness. This is part of the apparent paradox. Again, there's nothing mysterious about a system having a model of itself and being able to do reasoning on that model the same way it does reasoning on other models. Also again, nothing here supports the claim that the conscious mind is not divisible. It means that a conscious being can deal with Godelian questions in a way in which a machine cannot, because a conscious being can consider itself and its performance and yet not be other than that which did the performance. Whatever the conscious mind is, it appears to be housed in a physical information processing system, to wit, the human brain. If our current understanding about the kind of information processing brains are capable of is correct, brains fall into the class of automata and cannot ultimately do any processing task that cannot be done with a computer. The conscious mind can scrutinize its internal workings to an extent, but so can computer programs. Presumably the Goedelian & (more to the point) Turing limitations apply in principle to both. no extra part is required to do this: it is already complete, and has no Achilles' heel. This is an unsupported statement. The whole line of reasoning is rather loose; perhaps the author simply finds it psychologically difficult to suppose that he has any fundamental limitations. When we increase the complexity of our machines, there may, perhaps, be surprises in store for us.... Below a certain ``critical'' size, nothing much happens.... Turing is suggesting that it is only a matter of complexity [before?] a qualitative difference appears. Well, its very easy to build machines that are infeasible to predict. Such machines do not even have to be very complex in construction to be highly complex in behavior. Las Vegas is full of many examples of such machines. The idea that complexity in itself can result in a system able to escape Goedelian and Turing limitations is directly contradicted by the mathematical induction used in their proofs: The limitations apply to <> automata, not just to automata simple enough for us to inspect. Charlatans can claim any properties they want for mechanisms too complex for direct disproofs, but one need not work hard before dismissing them with indirect disproofs. This is why the patent office rejects claimed perpetual motion machines which supposedly operate merely by the complexities of their mechanical or electromagnetic design. It is also why journals of mathematics reject rediculously long proofs which claim to supply methods of squaring the circle, etc. No one examines such proofs to find the flaw, it would be a thankless task, and is not necessary. It is essential for the mechanist thesis that the mechanical model of the mind shall operate according to ``mechanical principles,'' that is, we can understand the operation of the whole in terms of the operation of its parts.... Certainly one expects that the behavior of physical objects can be explained at any level of reduction. However, consciousness is not necessarily a behavior, it is an ``experience'', whatever that is. Claims of consciousness, as in ``I assert that I am conscious'' are behavior, and can reasonably be subjected to a reductionist analysis. But whether this will shed any light on the nature of consciousness is unclear. A useful analogy is whether attacking a computer with a voltmeter will teach you anything about the abstractions ``program'', ``data structure'', ``operating system'', etc., which we use to describe the nature of what is going on there. These abstractions, which we claim are part of the nature of the machine at the level we usually address it, are not useful when examining the machine below a certain level of reduction. But that is no paradox, because these abstractions are not physical structure or behavior, they are our conceptualizations of its structure and behavior. This is as mystical as I'm willing to get in my analysis, but look at what Lucas does with it: if the mechanist produces a machine which is so complicated that this [process of reductionist analysis] ceases to hold good of it, then it is no longer a machine for the purpose of our discussoin, no matter how it was constructed. We should say, rather, that he had created a mind, in the same sort of sense as we procreate people at prsent. If someone produces a machine which which exhibits behavior that is infeasible to predict through reductionist methods, there is nothing fundamentally different about it. It is still obeying the laws of physics at all levels of its structure, and we can still in principle apply to it any desired reductionist analysis. We should certainly not claim to have produced anything special (such as a mind) just because we can't easily disprove the notion. When talking of [human beings and these specially complex machines] we should take care to stress that although what was created looked like a machine, it was not one really, because it was not just the total of its parts: one could not even tell the limits of what it could do, for even when presented with the Goedel type question, it got the answer right. There is simply no reason to believe that people can answer Goedelian questions any better than machines can. This bizarre notion that conscious objects can do such things is unproven and dubious. I assert that people cannot do these things, and neither can machines, and that the ability to escape from Goedel or Turing restrictions is irrelevant to questions of consciousness, since we are (experientially) conscious but cannot do such things. I find that most current analyses of consciousness are either mystical like the one I've addressed here, or simply miss the phenonmenon by attacking the system at a level of reduction beneath the level where the concept seems to apply. It is tempting to thing we can make scientific statements about consciousness just because we can experience consciousness ourselves. This idea runs aground when we find that this notion is dependent on capturing scientifically the phenomena of ``experience'', ``consciousness'' or ``self'', which I have not yet seen adequately done. Whether consciousness is a phenomenon with scientific existence, or whether it is an abstract creation of our conceptualizations with no external or reductionist existence is still undetermined. -Greg Davidson (davidson@sdcsvax.UUCP or davidson@nosc.ARPA)