The starting-point, it may be said, of Herbart’s psychology is a question which to the ordinary psychologist (and to the so-called scientific psychologist) has a secondary, if it have any interest. It was, he says, the problem of Personality, the problem of the Self or Ego, which first led to his characteristic conception of psychological method. “My first discovery,” he tells us(25), “was that the Self was neither primitive nor independent, but must be the most dependent and most conditioned thing one can imagine. The second was that the elementary ideas of an intelligent being, if they were ever to reach the pitch of self-consciousness, must be either all, or at least in part, opposed to each other, and that they must check or block one another in consequence of this opposition. Though held in check, however, these ideas were not to be supposed lost: they subsist as endeavours or tendencies to return into the position of actual idea, as soon as the check became, for any reason, either in whole or in part inoperative. This check could and must be calculated, and thus it was clear that psychology required a mathematical as well as a metaphysical foundation.” The place of the conception of the Ego in Kant’s and Fichte’s theory of knowledge is well known. Equally well known is Kant’s treatment of the soul-reality or soul-substance in his examination of Rational Psychology. Whereas the (logical) unity of consciousness, or “synthetic unity of apperception,” is assumed as a fundamental starting-point in explanation of our objective judgments, or of our knowledge of objective existence, its real (as opposed to its formal) foundation in a “substantial” soul is set aside as an illegitimate interpretation of, or inference from, the facts of inner experience. The belief in the separate unity and persistence of the soul, said Kant, is not a scientifically-warranted conclusion. Its true place is as an ineffaceable postulate of the faith which inspires human life and action. Herbart did not rest content with either of these—as he believed—dogmatic assumptions of his master. He did not fall in cheerfully with the idealism which seemed ready to dispense with a soul, or which justified its acceptance of empirical reality by referring to the fundamental unity of the function of judgment. With a strong bent towards fully-differentiated and individualised experience Herbart conjoined a conviction of the need of logical analysis to prevent us being carried away by the first-come and inadequate generalities. The Ego which, in its extremest abstraction, he found defined as the unity of subject and object, did not seem to him to offer the proper guarantees of reality: it was itself a problem, full of contradictions, waiting for solution. On the other hand, the real Ego, or self of concrete experience, is very much more than this logical abstract, and differs widely from individual to individual, and apparently from time to time even in the same individual.