The first half of Putnam's career was dominated in large part by tensions induced by his relationship to logical positivism and verificationism. The results were felt principally in the philosophy of science, the philosophy of language, and the philosophy of mind.

In philosophy of science, the main components were a developing realism, a rejection of the idea that any truths are absolutely a priori, and an assertion of the quasi-empirical character of mathematics. Putnam's claims here required underpinning with a realist theory of meaning. So in the philosophy of language, his focus was on terms that are central to scientific investigations (so-called “natural kind” terms), and his perspective tended increasingly towards externalism or anti-individualism. In the philosophy of mind, Putnam was stimulated mainly to think and rethink functionalism, understood narrowly here as a particular set of claims concerning the nature of mental phenomena.

The present aim is to distil from the details of this work a sense of the developing point of view from which it was written, first introducing its component parts in relation to sub-areas of philosophy, and then reassembling the overall perspective. In keeping with the interpretative focus of this part of the book, equal attention will be given to lesser known early writings in which the roots and first sketches of views are to be found (Putnam 1962a; 1962b; 1963a; 1965c; 1967c; 1968; 1971) as to the handful of classic and regularly anthologized papers in which those views are fully worked out and receive their official form.