More philosophical fun and games, some of a very high order, from the authors of, respectively, GÃ–del, Escher, Bach, and Brainstorms. Actually, this is an anthology, and there are some 17 other contributors, but Hofstadter and Dennett take turns commenting on all 27 pieces, so they can claim to have ""composed and arranged"" it. The central theme is the mind-body problem (does anything like the traditional notion of the soul really exist? are mental activities an epiphenomenon of the nervous system? is it true to say that ""I am a brain,"" ""I have a brain,"" or both, or neither?), especially as it arises in the question of artificial intelligence (Al). The bias here is empirical-scientific--we don't hear a word from an old-fashioned religious dualist--but Hofstadter and Dennett are wise enough to realize that, except for myopic reductionists, there's no way to settle these impossible issues; so they probe them, wittily, tentatively, non-dogmatically, from various angles. Richard Dawkins argues that human beings are ""survival machines"" for selfish genes, while Thomas Nagel brilliantly attacks such hard-line materialism in ""What Is It Like to Be a Bat?"" (Answer: we don't know.) In a reprint of a famous article, A. M. Turing maintains that machines can think, while John R. Searle counters that computers have a syntax, but no semantics; hence they lack intentionality, hence they can't think. In a psychological fable of fiendish ingenuity Dennett examines the contradictions implicit in separating brain from self. There are a couple of stories by Borges, three marvelous tales by Stanislaw Lem, and various good things by lesser-known writers. On the other hand, the three dialogues by Hofstadter might well have been dropped--he (like some of his critics) overrates his ability in that genre. Still, the writing is without exception polished or at least clear and readable, the topic is steadily interesting, and the dialectical fireworks make a fascinating spectacle.