Not all pragmatists are easily characterized. With the advent of postanalytic philosophy and the diversification of Anglo-American philosophy, many philosophers were influenced by pragmatist thought without necessarily publicly committing themselves to that philosophical school. Daniel Dennett, a student of Quine's, falls into this category, as does Stephen Toulmin, who arrived at his philosophical position via Wittgenstein, whom he calls "a pragmatist of a sophisticated kind" (foreword for Dewey 1929 in the 1988 edition, p. xiii). Another example is Mark Johnson whose embodied philosophy (Lakoff and Johnson 1999) shares its psychologism, direct realism and anti-cartesianism with pragmatism. Conceptual pragmatism is a theory of knowledge originating with the work of the philosopher and logician Clarence Irving Lewis. The epistemology of conceptual pragmatism was first formulated in the 1929 book "Mind and the World Order: Outline of a Theory of Knowledge".