Although the Oxford philosophers and the posthumous publication of Wittgenstein’s writings produced a revolution in Anglo-American philosophy, the branch of analytic philosophy that emphasized formal analyses by means of modern logic was by no means dormant. Since the appearance of Principia Mathematica in 1910–13, striking new findings have emerged in logic, many of which, though requiring for their understanding a high level of mathematical sophistication, are nevertheless important for philosophy.

Among those philosophers for whom symbolic logic occupied a central position was W.V.O. Quine, who taught at Harvard University from the 1930s to his retirement in 1978. Symbolic logic represented for him, as it did for many earlier analytic philosophers, the framework for the language of science. There were two important themes in his work, however, that represent significant departures from the positions of the logical atomists and the logical positivists. In the first place, Quine rejected the distinction between “analytic” statements, whose truth or falsity depends upon the meaning of the terms involved (e.g., “All bachelors are unmarried”), and “synthetic” statements, whose truth or falsity is a matter of empirical and observable fact (e.g., “It is raining here now”). This distinction, which had played an essential role in logical positivism and was thought by most empiricists to be the basis of the division between the deductive sciences (including philosophy) and the empirical ones, was impossible to draw, according to Quine. In the course of his argument, a similar doubt was cast upon concepts traditional not only to philosophy but also to linguistics—in particular, the concept of synonymy, or sameness of meaning.

The second important departure of Quine’s philosophy was his attempt to show that science can be successfully conducted without reference to what he calls “intensional entities.” Among such entities are many items that analytic philosophers had thought they could talk about without difficulty, such as meanings, propositions, and the properties—attributed to statements—of being necessarily true or possibly true. Because he did not accept the existence of entities that did not need to be referred to in successful scientific theories, Quine concluded that we have no good reason to believe that intensional entities exist. Quine’s work, though by no means widely accepted, has made analytic philosophers at least wary of uncritically accepting certain of their standard distinctions.

Since the mid-20th century, there has been considerable interaction between analytic philosophy and the science of linguistics. This interaction did not occur in earlier years because analytic philosophers, at least until the later Wittgenstein, had almost always considered their study of language to be a priori and thus unconcerned with empirical facts about particular languages. However, the advent of theories of transformational-generative grammar in the work of the American linguist Noam Chomsky and others from the late 1950s, and in particular Chomsky’s theory of innate linguistic knowledge in the form of a “universal grammar,” produced a revolution in linguistics and exerted a powerful influence in analytic philosophy, especially in the fields of epistemology and the philosophy of mind. At first, some analytic philosophers regarded Chomsky’s analyses, in which the surface syntactic structures of sentences were generatively derived from underlying “deep structures,” as a possible model for philosophical analysis. It was subsequently considered, however, that, whereas Chomsky’s way of looking at grammar had contributed valuable concepts to philosophy, it was not an appropriate methodology for doing analytic philosophy. The interchange between linguists and philosophers, however, has continued.