Although variants of pragmatism were never absent from discussion, in the second third of the century a number of vigorous professionals conducted a refined epistemological critique of the empirical bases of knowledge. Pragmatic assumptions were called into question as realistic doctrines made a comeback. C. I. Lewis's Mind and the World-Order (1929) was a critical text as were the essays of Wilfrid Sellars written mainly in the 1950s and 1960s. The intellectual migration from Europe, caused by the rise of totalitarianism in the 1930s, contributed to this argument when a uniquely stringent empiricism, logical positivism, made an impact on debate after World War II.
These developments gave American thought worldwide honor in professorial circles, but came at great cost to the public presence of philosophy and even to its audience in the academy. In contrast to what philosophy had been, both in and outside the university, during the period of James, Royce, and Dewey, philosophy after World War II had narrow concerns. The 1960s accentuated the new social role when the cultural radicalism and spirit of rebellion surrounding the Vietnam War further exacerbated the problems of professional speculation.
In the last quarter of the century a cacophony of voices competed for attention in the world of philosophy. The most influential movement still had a connection to Cambridge. Originating in the 'pragmatic analysis' developed after World War II by Nelson Goodman and Willard Quine and the ruminations of Sellars, this movement evolved from an extraordinary publication of 1962, The Structure of Scientific Revolutions by Thomas Kuhn. Although Kuhn's work was ambiguous, it soon justified an attack on the objectivity of science. The publications of Richard Rorty in the last twenty years of the century gave a deeper philosophical justification for these ideas.
The last part of this history traces these complicated developments. They took American philosophy from the high point of achievement and public influence of the classic pragmatists to a confused and less potent role at the end of the twentieth century.