A critique of pure reason 1

In 1978, Patrick Hayes promulgated the Naive Physics Manifesto. (It finally appeared as an “official” publication in Hobbs and Moore 1985.) In this paper, he proposed that an allout effort be mounted to formalize commonsense knowledge, using first-order logic as a notation. This effort had its roots in earlier research, especially the work of John McCarthy, but the scope of Hayes’s proposal was new and ambitious. He suggested that the use of Tarskian seniantics could allow us to study a large volume of knowledge-representation problems free from the confines of computer programs. The suggestion inspired a small community of people to actually try to write down all (or most) of commonsense knowledge in predictate calculus. He launched the effort with his own paper on “Liquids” (also in Hobbs and Moore 1985), a fascinating attempt to fix ontology and notation for a realistic domain. Since then several papers in this vein have appeared (Allen 1984; Hobbs 1986; Shoham 1985). I myself have been an enthusiastic advocate of the movement, having written general boosting papers (1978) as well as attempts to actually get on with the work. (1982, 1985). I even coauthored a textbook oriented around Hayes’s idea (Charniak and McDermott 1985). It is therefore with special pain that I produce this report, which draws mostly negative conclusions about progress on Hayes’s project so far, and the progress we can expect. In a nutshell, I will argue that the skimpy progress observed so far is no accident, that in fact it is going to be very difficult to do much better in the future. The reason is that the unspoken premise in Hayes’s arguments, that a lot of reasoning can be analyzed as deductive or approximately deductive, is erroneous. I don’t want what I say in this paper to be taken as a criticism of Pat Hayes, for the simple reason that he is not solely to blame for the position I am criticizing. I will therefore refer to it as the “logicist” position in what follows. It is really the joint work of several people, including John McCarthy, Robert Moore, James Allen, Jerry Hobbs, Patrick Hayes, and me, of whom Hayes is simply the most eloquent.