Intersubjectivity, the cooperation of two or more minds, is basic to human behavior, yet eludes the grasp of psychiatry. This paper traces the dilemma to the “problem of other minds” assumed with the epistemologies of modern science. It presents the solution of Wittgenstein's later philosophy, known for his treatment of other minds in terms of “human agreement in language.”Unlike recent studies of “Wittgenstein's psychology,” this one reviews the Philosophical Investigations' “private language argument,” the crux of his mature views on mind. (...) It reads that argument as recording his shift from the modern egocentric paradigm of mind to an intersubjective one.The paper contrasts the merits of Wittgenstein's reduction of subject and object to grammar with the problems of Freud's metapsychological reduction. It shows how Wittgenstein's intersubjective method avoids the excesses of behaviorism and phenomenology, offering a specifically human way to adapt mechanistic and interpretive means to the communicative ends of psychiatry. (shrink)