Philosophical psychology reflects upon the aims and the concepts of empirical psychology. First published in 1979, Philosophical Problems in Psychology argues that empirical psychology must be founded upon the language of rationality, for actions and the reasons people give for their actions are at the heart of human behaviour. This thesis is defended in the contributions to Part I which assert that psychology must take the form of an elaboration of common sense. But the authors in Part II maintain that psychology may remain faithful to this insight whilst still developing more sophisticated models of behaviour. The use of computer models, Piaget’s views on the effects of internalization and a discussion of the geometry of phenomenal space provide illustrations. Part III contains three papers which explore the limitations of theoretical statements which emphasize our construction of reality. The pertinence of the computer analogy is disputed, subject-centred models are scrutinized in the light of phenomenology, and the role of theory in psychotherapy is critically discussed.