ABSTRACT
Explanation presupposes a foundation of what we like to regard as established fact. In everyday life we can work from a large number of practical certainties, such as our experiences of gravity, weight, volume, sharpness and bluntness, heat and cold, and the constant properties of known materials. But we have no such tangible and verifiable experience of what causes behaviour. Through the ages, therefore, man has been led to postulate either, as Plato did, a soul as the motive force, with its various parts initiating different types of behaviour; or, as in the case of the philosophers of the Renaissance, that differences in the behaviour of individuals arise from the admixture of the elements of earth, fire, air, and water in each person's constitution. In more modern times instincts, drives, ‘motives’, or other sources of psychic energy have been made to serve as the explanatory bedrock. Needless to say, there is no means of verifying the existence of any of these supposed bases of human motivation, nor do the facts of behaviour force us to conclude that they must exist. Man has invented them in his attempt to explain himself.
