ABSTRACT
Since the sensory aspect of perception can be focalized, psychologists have often tried to describe perception in terms of sensation. This method of procedure, however, is based upon the assumption that a perception can be analyzed into elements which are the perception. Having found reason to doubt whether any psychological or physiological process is ever a mere sum of elementary constituents, we have denied this assumption, and have maintained, instead, that every process is a unitary whole, in the differentiation of which new wholes are created. We have been able to trace the creation of these new wholes in the course of both phylogenetic and ontogenetic development. Among the differentiations which take place in the behavior of an individual certain events emerge with a compactness and completeness that defines their phenomena as perceptions.
