 The most philosophically interesting questions arise for those cases of conflict that present themselves again and again. We speak in the same breath of a responsible human agent who is, and acts, in a world that is a field of physical, chemical, and biological causes and effects. “Men must, we feel, be free; yet they must, we feel, be amenable to prediction and explanation. Their actions cannot be mechanical. Yet also they cannot be unmechanical” (1962a, 444). From the point of view of laymen and scientists who are actually exploring the world, we find out what there is by perceiving it; yet from the point of view of the inquirer into the mechanism of perception, what we perceive never coincides with the world (1954, 2). The reconciliation of these convictions, an answer to the question how this could be, belongs to philosophy.