Kinship can make for trouble. This is true for the relations between the various disciplines of knowledge, such as the sciences. It is also true for the present interaction between psychology and philosophy, about which I wish to register a complaint in the following. To be sure, if one prefers to cling strictly to one's own specialty, one need not worry about contradictions between neighboring occupations. That, however, is a convenience one cannot afford if one is convinced, as I am, that one's own field of work and philosophy are inseparable.

For my purpose, philosophy is not a self-contained discipline; it is the crowning superstructure of efforts in the various fields of study to advance to ultimate principles. It is those principles on which the work of philosophy is based. And just as philosophy is threatened with sterility when it fails to replenish its resources from pertinent areas of knowledge, work in any specialty may succumb to narrow drudgery when it no longer focuses on the larger objectives that are the territory of the philosopher.

This symbiotic relationship seems to me particularly indispensable for psychology. Philosophy must refer to other sciences, such as physics or biology, when required by its particular tasks to do so. Psychology, however, is always involved in this symbiosis because philosophy deals with the mind and the mind is the subject of psychology.

Conversely, in my own work on the psychology of art, I find it hard to decide where, for example, my study of the artist's dealing with the world of reality trespasses on epistemology as a chapter of philosophy. Or, to pick another example, where does an invest