About
Hilary Putnam (1926–2016) was an American philosopher and one of the central figures in analytic philosophy of mind, spending most of his career as Cogan University Professor at Harvard. In the late 1960s he developed functionalism — the view that mental states are defined by their functional role, not their physical substrate — arguing via 'multiple realizability' that a mind could in principle be realized in silicon as well as neurons. It became the philosophical license for the whole idea that machines might think. Characteristically, he later became one of functionalism's most forceful critics, rejecting it in Representation and Reality (1988). He is equally known for semantic externalism — 'meaning ain't in the head' — and the Twin Earth thought experiment.
Key Contributions
- Developed functionalism and multiple realizability, the argument that mind is substrate-independent
- Later repudiated functionalism in Representation and Reality (1988), a rare public reversal
- Formulated semantic externalism and the Twin Earth thought experiment ('meaning ain't in the head')
- Contributed to the causal theory of reference alongside Saul Kripke
- Proved the Davis–Putnam foundations of automated theorem proving and worked on Hilbert's tenth problem
Questions they sharpened View the streams
Videos & Interviews
The Philosophy of Science - Hilary Putnam & Bryan Magee
Putnam and Bryan Magee discuss the philosophy of science in the classic 1977 BBC 'Men of Ideas' series.
View Details
Hilary Putnam Interview - Mind, Truth & Science (1998)
A wide-ranging interview touching on functionalism, externalism, and the Turing Test.
View DetailsPapers & Publications
Connections
Alan Turing
Influenced byMathematician & Computer Science Pioneer
Putnam's machine-state functionalism, worked out from 'Minds and Machines' (1960) to 'Psychological Predicates' (1967), took Turing's abstract machine as the model of a mind: mental states are machine-table states, defined by their relations to inputs, outputs and one another, whatever they happen to be made of. That move turned Turing's 1950 question about behavior into a theory of what minds are, and it is the philosophical license behind every claim that silicon could think. Putnam later abandoned it, but the license had already been issued.
plato.stanford.edu · en.wikipedia.org
Rudolf Carnap
DebatedPhilosopher & Logician
In the 1963 Schilpp volume on Carnap, Putnam read Carnap's program of inductive logic as the design of a universal learning machine, and gave a diagonal proof that no computable confirmation function of Carnap's kind can learn every computable regularity. Carnap's reply conceded something real: that how scientists accept hypotheses may depend on which hypotheses happen to be proposed, and in what order. The exchange is an early, exact statement of a limit machine learning still lives inside, that every learner has an inductive bias and none learns everything.
plato.stanford.edu · Putnam, "'Degree of Confirmation' and Inductive Logic", in Schilpp (ed.), The Philosophy of Rudolf Carnap (Open Court, 1963), pp. 761–783 · Sterkenburg, "Putnam's Diagonal Argument and the Impossibility of a Universal Learning Machine", Erkenntnis (2019)
