The Croonian lecture, 1990. The interdependence of the behavioural sciences.

It is true to say that we live in a time of rapid social change. But it is easy to forget that we also live in, or one could say have lived through, a time of rapid change in the nature of science. The exponential growth of science, and its magnificent achievements, have been accompanied by its disintegration into a multiplicity of subsciences. It is no longer possible for an individual to be an all-rounder, and that makes it the more important that collectively we should not lose sight of the essential unity of the scientific enterprise. My aim here is to provide a framework to illustrate essential interrelations between the various subsciences that deal with behaviour and its underlying mech­ anisms, and to emphasize that the research worker must cross and recross the boundaries between them.