Analytic & pragmatist · 1926–2016
Hilary Putnam
Harvard philosopher who launched functionalism, then criticised it
Mental states are functional states that could be realised in many materials; and “meanings just ain’t in the head”: what our words refer to depends on the world. He later turned against functionalism and toward pragmatism.
Life and thought
Hilary Putnam (1926–2016) studied with Hans Reichenbach at UCLA and first made his name in mathematical logic, contributing to the solution of Hilbert’s tenth problem. He taught at Princeton and MIT and from 1965 at Harvard. Politically active, he joined a Maoist group in the late 1960s, and he was famous for changing his mind in public when he thought his earlier arguments had failed.
In the 1960s Putnam proposed functionalism: a mental state such as pain is defined by its role, by what causes it and what it causes, not by what it is made of, so it could be realised in a human brain, an octopus or a computer. In “The Meaning of ‘Meaning’” (1975) he imagined Twin Earth, where a liquid exactly like water is chemically XYZ, not H₂O. A Twin Earthling’s word “water” refers to XYZ even though her thoughts feel the same as ours, so “meanings just ain’t in the head”. Later he criticised functionalism, rejected the idea of a “God’s-eye view” of reality, and ended close to the pragmatism of James and Dewey.