Wilfrid Sellars (1912-89) has been called "the most profound and systematic epistemological thinker of the twentieth century" (Robert Brandom). He was in many respects ahead of his time, and many of his innovations have become widely acknowledged, for example, his attack on the "myth of the given", his functionalist treatment of intentional states, his proposal that psychological concepts are like theoretical concepts, and his suggestion that attributions of knowledge locate the knower "in the logical space of reasons". However, while many philosophers have begun to acknowledge Sellars's...