What is good thinking? To ask this is to pose one of the most venerable questions of scholarship. Aristotle’s (350 B. C. E.) analysis of syllogisms, Bacon’s (1620/1878) account of scientific inquiry, Kant’s (1785/1994) categorical imperative, Von Neumann and Morgenstern’s (1944) exposition of game theory, Inhelder and Piaget’s (1958) notion of formal operational thinking, Wertheimer’s (1945) formulation of productive thinking all set forth normative conceptions of various kinds of thinking. Contemporary work expands, ramifies, and refines the analysis into many particular kinds of thinking (e.g. Baron, 1985; Basseches, 1984; Case, 1992; Elgin, 1996; Langer, 1989; Paul, 1990; Toulmin, 1958).