This paper aims to clarify certain assumptions, methods, and conclusions which have tended to divide philosophy and psychology. In order to demonstrate these differences, I have selected certain issues and developments within the philosophy of language which are relevant to behaviorism and cognitive theory. What I will demonstrate is that the assumptions, methods, and conclusions of an enquiry are often related to beliefs about the duality of the human subject. I also point out that philosophers are not unanimous about the existence of this alleged duality. Accordingly, I show that when philosophers abandon the dualistic interpretation, they also reject the idea that philosophy and psychology are fundamentally irreconcilable disciplines.