Wednesday, March 14, 2007

Common Sense and the Question of the Underlying Foundations of Thought and Consciousness

In legal theorizing about inference there is much talk about "generalizations" and, on inspection, these generalizations are often common sense generalizations. In Artificial Intelligence -- or, if you prefer, "computational intelligence" -- there has been much interest in and talk about common sense generalizations. I recently mentioned the pioneering work of John McCarthy, who is profoundly interested in, not only AI, but also commonsense principles about the world. He is not alone; Douglas Lenat is another example, if possibly a curious one. (He is reported to have said that "intelligence is 10 million [common sense?] rules.") Fuzzy probability and its offshoots are another example of AI theorizing that takes common sense principles very seriously.

Some neuroscience, by contrast, seems determined to do away with common sense and to ascertain, via neuroscience, what and how human beings really think. The work of the Churchlands and of Daniel Dennett strongly tends in this direction, as does perhaps the "neurolaw" that Jeffrey Rosen of the NYTimes recently described.

The question of whether what we think we think is what and how we actually think is, scientifically speaking, an unresolved question. While it seems to be true that human thought as we know it cannot take place without material entities such as the brain, the nervous system, and a functioning heart, it must not be too readily supposed that in time, as all is revealed, it will be revealed that common sense thinking is entirely epiphenomenal, entirely an elaborate artifice, as it were -- much less that it will necessarily be shown that human thought is, not only associated with and dependent on the existence of, say, physical or neural processes in the brain, but also that human thought is, in some fundamental sense, superfluous to such "[allegedly] determinative material ["neural"?] substrata "processes"?]." The reduction of human thought to the workings of neural pathways is not yet at hand -- this condition is not yet at hand in the sense that we do not yet know how to replace allegedly epiphenomenal human reasoning with the workings of neural pathways in the human brain or, more broadly, in the human body.

Is it possible that human thought will never be reducible to the workings of such pathways or to something analogous to (and perhaps "deeper" than) such pathways? The answer, I think, depends at present more on faith than on science -- more on what one believes, without proof, about the fundamental nature of things. I would offer just a word of caution to the new reductionists, those who aspire to reduce all thought to "material neural pathways" [perhaps an oxymoron]: The sense of this nonexpert in AI matters is that at present it can be said -- perhaps counter-intuitively in the eyes of some observers -- that some AI approaches that emphasize the reality and efficacy of arguably epiphenomenal ways of thinking about the world do, to some extent, allow the creation of artificial mechanisms that seem to have some capacity to deal with the workings of the world. I think here principally of the successes of soft computing in controlling matters such as the scheduling of Japanese trains and the focusing mechanisms in cameras. See the interesting Wikipedia article on fuzzy control systems. Perhaps it will turn out that common sense has vastly more "intelligence" than is sometimes attributed to it.

But we must not be too smug intellectually. Another important development in recent years, partly the result again of research in AI, is our increasing awareness of the extent to which human inference involves and requires what Helmholtz called "unconscious inference." As I see it, a new Aristotle will soon emerge. This new Aristotle will be a thinker who will suggest how these two visions of human information processing -- commonsense reasoning and tacit, or unconscious, inference -- combine in a way that does not annihilate the truth and reality of either of them, and that makes it possible for human beings to function in the world -- in a way that perhaps even makes it possible for human beings to reflect on their position in the world, i.e., to philosophize.

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