Both the psychology of perception and the philosophy of perception seem to show a new face when the process is considered at its own level, distinct from that of sensation. Unfamiliar conceptions in physics, anatomy, physiology, psychology, and phenomenology are required to clarify the separation and make it plausible. But there have been so many dead ends in the effort to solve the theoretical problems of perception that radical proposals may now be acceptable. Scientists are often more conservative than philosophers (...) of science. I end, therefore, as I began, with a plea for help. (shrink)

The A.W. Mellon lectures in the fine arts 1956, National Gallery of Art, Washington.

It is proposed that the Darwinian theoretical approach and account of living systems has not yet been clearly given. A first approximation to this is attempted, focussing on behavior in evolving environments. A theoretical terminology is defined emphasizing the mutuality of organism and environment and the existence of biologically theoretical entities.