Portal:Philosophy/Selected article/30

Hilary Whitehall Putnam (born July 31, 1926) is an American philosopher who has been a central figure in analytic philosophy since the 1960s, especially in philosophy of mind, philosophy of language, and philosophy of science. He is known for his willingness to apply an equal degree of scrutiny to his own philosophical positions as to those of others, subjecting each position to rigorous analysis until he exposes its flaws. As a result, he has acquired a reputation for frequently changing his own position.

In philosophy of mind, Putnam is known for his argument 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. In philosophy of language, along with Saul Kripke and others, he developed the causal theory of reference, and formulated an original theory of meaning, inventing the notion of semantic externalism based on a famous thought experiment called Twin Earth.

In philosophy of mathematics, he and his mentor W. V. Quine developed the "Quine-Putnam indispensability thesis," an argument for the reality of mathematical entities, later espousing the view that mathematics is not purely logical, but "quasi-empirical." In the field of epistemology, he is known for his critique of the well known "brain in a vat" thought experiment. This thought experiment appears to provide a powerful argument for epistemological skepticism, but Putnam challenges its coherence. In metaphysics, he originally espoused a position called metaphysical realism, but eventually became one of its most outspoken critics, first adopting a view he called "internal realism", which he later abandoned in favor of a pragmatist-inspired direct realism. Putnam's "direct realism" aims to return the study of metaphysics to the way people actually experience the world, rejecting the idea of mental representations, sense data, and other intermediaries between mind and world.