Putnam applied equal scrutiny to his own philosophical positions as to those of others, subjecting each position to rigorous analysis until he exposed its flaws.[8] As a result, he acquired a reputation for frequently changing his positions.[9] In philosophy of mind, Putnam argued against the type-identity of mental and physical states based on his hypothesis of the multiple realizability of the mental, and for the concept of functionalism, an influential theory regarding the mind–body problem.[5][10] In philosophy of language, along with Saul Kripke and others, he developed the causal theory of reference, and formulated an original theory of meaning, introducing the notion of semantic externalism based on a thought experiment called Twin Earth.[11]
In his later work, Putnam became increasingly interested in American pragmatism, Jewish philosophy, and ethics, engaging with a wider array of philosophical traditions. He also displayed an interest in metaphilosophy, seeking to "renew philosophy" from what he identified as narrow and inflated concerns.[17] He was at times a politically controversial figure, especially for his involvement with the Progressive Labor Party in the late 1960s and early 1970s.[18]
^Putnam, Hilary (1978). ""Realism and reason", Presidential Address to the Eastern Division of the American Philosophical Association, December 1976". Meaning and the Moral Sciences. Routledge and Kegan Paul. pp. 123–140. ISBN978-0-710-08754-6. OCLC318417931.
^King, P. J. (2004). One Hundred Philosophers: The Life and Work of the World's Greatest Thinkers. Barron's. p. 170. ISBN978-0-764-12791-5. OCLC56593946.
^Putnam, H. (1990). Conant, J. F. (ed.). Realism with a Human Face. Cambridge, Massachusetts: Harvard University Press. ISBN978-0-674-74945-0. OCLC1014989000.