FACULTY PSYCHOLOGY is the name given to the older psychology which "explained" the various mental processes by reference to corresponding "faculties" (Latin facultas, a capacity) which exercised them. Thus the process of thinking was explained by reference to the faculty of "understanding" or of "reason," the process of volition was referred to the faculty of "will," and so on. Although the faculty psychology has been frequently derided from the days of Locke onwards, it is not entirely dead, for it still seems to haunt some of the latest books on psychology in the guise of "abilities."