- The area of artificial intelligence (AI) differs from that of natural intelligence in at least three respects. First, in AI one is perforce limited to the use of formalized behavioral data or "output" as a basis for making inferences about one's subjects. (The situation is no different, however, in the fields of history and archaeology.) Second, by convention, if nothing else, in AI one must ordinarily assume, until proved otherwise, that one's subject has no more mentality than a rock; whereas in the area of natural intelligence one can often get away with the opposite assumption, namely, that until proved otherwise, one's subject can be considered to be sentient. Third, in AI analysis is ordinarily limited to questions regarding the "structure" of intelligence, whereas a complete analysis of natural intelligence must also consider questions of function, development, and evolution.
- In other respects, however, it seems to me that the problems of inferring mental capacities are very much the same in the two areas. And the whole purpose of the Turing test (or the many counterparts to that test which are the mainstay of comparative psychology) is to devise a clear set of rules for determining the status of subjects of any species, about whose possession of a given capacity we are uncertain. This is admittedly a game, and it cannot be freed of all possible arbitrary aspects any more than can, say, the field of law. Furthermore, unless everyone agrees to the rules of the game, there is no way to prove one's case for (or against) a given capacity with absolute and dead certainty.
- As I see it. Searle quite simply refuses to play such games, at least according to the rules proposed by AI. He assigns himself the role of a judge who knows beforehand in most cases what the correct decision should be. And he does not, in my opinion, provide us with any decision rules for the remaining (and most interesting) undecided cases, other than rules of latter-day common sense (whose pitfalls and ambiguities are perhaps the major reason for devising objective tests that are based on performance rather than physical characteristics such as species, race, sex, and age).
- Let me be more specific. First of all, the discussion of "the brain" and "certain brain processes" is not only vague but seems to me to displace and complicate the problems it purports to solve. In saying this I do not imply that physiological data are irrelevant; I only say that their relevance is not made clear, and the problem of deciding where the brain leaves off and non-brain begins is not as easy as it sounds. Indeed. I doubt that many neuroanatomists would even try to draw any sharp and unalterable line that demarcates exactly where in the animal kingdom "the brain" emerges from "the central nervous system"; and I suspect that some of them would ask, Why single out the brain as crucial to mind or intentionality? Why not the central nervous system or DNA or (to become more restrictive rather than liberal) the human brain or the Caucasian brain? Precisely analogous problems would arise in trying to specify for a single species such as man precisely how much intact brain, or what parts of it, or which of the "certain brain processes," must be taken into account and when one brain process leaves off and another one begins. Quite coincidentally, I would be curious as to what odds Searle would put on the likelihood that a neurophysiologist could distinguish between the brain processes of Searle during the course of his hypothetical experiment and the brain processes of a professor of Chinese. Also, I am curious as to what mental status he would assign to, say, an earthworm.
- Second, it seems to me that, especially in the domain of psychology, there are always innumerable ways to skin a cat, and that these ways are not necessarily commensurate, especially when one is discussing two different species or cultures or eras. Thus, for example, I would be quite willing to concede that to "acquire the calculus" I would not require the intellectual power of Newton or of Leibnitz, who invented the calculus. But how would Searle propose to quantity the relative "causal powers" that are involved here, or how would he establish the relative similarity of the "effects"? The problem is especially difficult when Searle talks about subjects who have "zero understanding," for we possess no absolute scales or ratio scales in this domain, but only relativistic ones. In other words, we can assume by definition that a given subject may be taken as a criterion of "zero understanding," and assess the competence of other subjects by comparing them against this norm; but someone else is always free to invoke some other norm. Thus, for example, Searle uses himself as a standard of comparison and assumes he possesses zero understanding of Chinese. But what it I proposed that a better norm would be, say, a dog? Unless Searle's performance were no better than that of the dog, it seems to me that the student of AI could argue that Searle's understanding must be greater than zero, and that his hypothetical experiment is therefore inconclusive; that is, the computer, which performs as he did, cannot necessarily be said to have zero understanding either.
- In addition to these problems, Searle's hypothetical experiment is based on the assumption that AI would be proved "false" if it could be shown that even a single subject on a single occasion could conceivably pass a Turing test despite the fact that he possesses what may be assumed to be zero understanding. This, in my opinion, is a mistaken assumption. No student of AI would, to my knowledge, claim infallibility. His predictions would be at best probabilistic or statistical; and, even apart from problems such as cheating, some errors of classification are to be expected on the basis of "chance" alone. Turing, for example, predicted only that by the year 2000 computers will be able to fool an average interrogator on a Turing test, and be taken for a person, at least 30 times out of 100. In brief, I would agree with Searle if he had said that the position of strong AI is unprovable with dead certainty; but by his criteria no theory in empirical science is provable, and I therefore reject his claim that he has shown AI to be false.
- Perhaps the central question raised by Searle's paper is, however, Where does mentality lie? Searle tells us that the intelligence of computers lies in our eyes alone. Einstein, however, used to say, "My pencil is more intelligent than I"; and this maxim seems to me to come at least as close to the truth as Searle's position. It is quite true that without a brain to guide it and interpret its output, the accomplishments of a pencil or a computer or of any of our other "tools of thought" would not be very impressive. But, speaking for myself, I confess I'd have to take the same dim view of my own accomplishments. In other words, I am quite sure that I could not even have "had" the thoughts expressed in the present commentary without the assistance of various means of externalizing and objectifying "them" and rendering them accessible not only for further examination but for their very formulation. I presume that there were some causal connections and correspondences between what is now on paper (or is it in the reader's eyes alone?) and what went on in my brain or mind; but it is an open question as to what these causal connections and correspondences were. Furthermore, it is only if one confuses present and past, and internal and external happenings with each other, and considers them a single "thing," that "thinking" or even the causal power behind thought can be allocated to a single "place" or entity. I grant that it is metaphorical if not ludicrous to give my pencil the credit or blame for the accomplishment of "the thoughts in this commentary." But it would be no less metaphorical and ludicrous - at least in science, as opposed to everyday life - to give the credit or blame to my brain as such. Whatever brain processes or mental processes were involved in the writing of this commentary, they have long since been terminated. In the not-too-distant future not even "I" as a body will exist any longer. Does this mean that the reader of the future will have no valid basis for estimating whether or not I was (or, as a literary figure, "am") any more intelligent than a rock? I am curious as to how Searle would answer this question. In particular, I would like to know whether he would ever infer from an artifact or document alone that its author had a brain or certain brain processes - and, if so, how this is different from making inferences about mentality from a subject's outputs alone.
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- Blue: Text by me; © Theo Todman, 2019
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