Dummett Michael A. E. (b.1925), British philosopher of language, logic, and mathematics, noted for his sympathy for metaphysical antirealism and for his exposition of the philosophy of Frege. Dummett regards allegiance to the principle of bivalence as the hallmark of a realist attitude toward any field of discourse. This is the principle that any meaningful assertoric sentence must be determinately either true or else false, independently of anyone’s ability to ascertain its truth-value by recourse to appropriate empirical evidence or methods of proof. According to Dummett, the sentences of any learnable language cannot have verification-transcendent truth conditions and consequently we should query the intelligibility of certain statements that realists regard as meaningful. On these grounds, he calls into question realism about the past and realism in the philosophy of mathematics in several of the papers in two collections of his essays, Truth and Other Enigmas (1978) and The Seas of Language (1993).
In The Logical Basis of Metaphysics (1991), Dummett makes clear his view that the fundamental questions of metaphysics have to be approached through the philosophy of language, and more specifically through the theory of meaning. Here his philosophical debts to Frege and Wittgenstein are manifest. Dummett has been the world’s foremost expositor and champion of Frege’s philosophy, above all in two highly influential books, Frege: Philosophy of Language (1973) and Frege: Philosophy of Mathematics (1991). This is despite the fact that Frege himself advocated a form of Platonism in semantics and the philosophy of mathematics that is quite at odds with Dummett’s own anti-realist inclinations. It would appear, however, from what Dummett says in Origins of Analytical Philosophy (1993), that he regards Frege’s great achievement as that of having presaged the ‘linguistic turn’ in philosophy that was to see its most valuable fruit in the later work of Wittgenstein. Wittgenstein’s principle that grasp of the meaning of a linguistic expression must be exhaustively manifested by the use of that expression is one that underlies Dummett’s own approach to meaning and his anti-realist leanings. In logic and the philosophy of mathematics this is shown in Dummett’s sympathy for the intuitionistic approach of Brouwer and Heyting, which involves a repudiation of the law of excluded middle, as set forth in Dummett’s own book on the subject, Elements of Intuitionism (1977). See also BROUWER, MATHEMATICAL INTU- ITIONISM , METAPHYSICAL REALISM , WITTGEN – STEI. E.J.L.