A modern American
philosopher, prominent in most fields. Perhaps his best known concept is that of
Twin Earth, which is a faraway planet exactly like Earth and speaking the same languages, except for some virtually undetectable difference, such as that the common liquid they call '
water' is actually not chemically H
2O, or that the animals they call '
horses' have actually evolved in a different family. Putnam then discusses whether an Earthling and a Twin-Earthling
mean the same thing by these terms.
He is also responsible for the original formulation of functionalism in theory of mind, in the 1950s when the Turing machine and computation were shiny new concepts. He argued that a mental state could be realized by some specific configuration of a computing machine as long as the machine state performed the same function: it didn't depend on any underlying basic property of the machine or brain. Although this was extremely influential, and continues to be, Putnam himself eventually disavowed functionalism.
He has ranged over a lot of thought, and to some extent changed over the years, and I have never had a simple impression of what "kind" of thing Putnam professes, or what his philosophy is in a nutshell, and I don't mean that dismissively. He discusses questions rather than proposing overarching theories. In this he followed in the analytic philosophy tradition.
Later he moved to adopt a more pragmatist position, contrasting this "pragmatic realism" with an earlier, more scientifically-inclined "metaphysical realism", which he had derived from early training in logical positivism. But he has never adopted the full-blown relativist tendencies of some American-school philosophers identifying themselves with pragmatism. In fact the persistent feeling you get about his claims is that he's trying to maintain a middle position with the best of both opposing arguments; and this can have a weakening effect, because such a thing is harder to justify convincingly than extreme positions, which at least can have a sharp initial appeal.
Born in Chicago in 1926, he graduated from the University of Pennsylvania in 1948, majoring in mathematics and philosophy, and got his Ph.D. from UCLA in 1951.
He taught maths at Princeton until 1961 then switched to philosophy of science at MIT till 1976, then returned to mathematics at Harvard.
http://spazioinwind.libero.it/albgaz/putnam/puteng.html is a good thorough site with full bibliography and lots more, including links to texts
http://www.xrefer.com/entry.jsp?xrefid=553313&secid=.1.- from an on-line version of The Oxford Companion to Philosophy
http://www.artsci.wustl.edu/~philos/MindDict/putnam.html on functionalism