I suggest that a conflict between two philosophical models of the mind so far unremarked in discussions of psychoanalysis is at the heart of questions about its status as a science, the objectivity of psychoanalytic interpretations, and the nature of the unconscious. In philosophy one model is embodied in the tradition of Descartes, Hobbes, Locke, Kant, among many others, which construes thought as prior to and independent of language. According to this tradition the mind is self-contained and mental contents or "ideas" are essentially subjective phenomena. It follows that knowledge of other minds and the material world is radically problematic. In the second and more contemporary model the phenomenon of meaning is dependent on interactions between minds, and between mind and the world. Since meaning is understood to be intrinsically social, so in an important sense is mind. I develop this second philosophic model, indicating its relevance for psychoanalysis. I also point out some of the contributions of psychoanalysis to philosophy of mind.