The Wolffian school, which Herbart (not less than Kant) found in possession of the field, and which in Germany may be taken to represent only a slight variant of the half-and-half attitude of vulgar thought, was entrenched in the psychology of faculties. Empirical psychology, said Wolff(35), tells the number and character of the soul's faculties: rational psychology will tell what they "properly" are, and how they subsist in soul. It is assumed that there are general receptacles or tendencies of mental operation which in course of time get filled or qualified in a certain way: and that when this question is disposed of, it still remains to fix on the metaphysical bases of these facts.
That a doctrine of faculties should fix itself in psychology is not so wonderful. In the non-psychical world objects are easily discriminated in space, and the individual thing lasts through a time. But a phase of mind is as such fleeting and indeterminate: its individual features which come from its "object" tend soon to vanish in memory: all freshness of definite characters wears off, and there is left behind only a vague "recept" of the one and same in many, a sort of hypostatised representative, faint but persistent, of what in experience was an ever-varying succession. We generalise here as elsewhere: but elsewhere the many singulars remain to confront us more effectually. But in Mind the immense variety of real imagination, memory, judgment is forgotten, and the name in each case reduced to a meagre abstract. Thus the identity in character and operation, having been cut off from the changing elements in its real action, is transmuted into a substantial somewhat, a subsistent faculty. The relationship of one to another of the powers thus by abstraction and fancy created becomes a problem of considerable moment, their causal relations in particular: till in the end they stand outside and independent of each other, engaged, as Herbart says, in a veritable _bellum omnium contra omnes_.
But this hypostatising of faculties becomes a source of still further difficulties when it is taken in connexion with the hypostasis of the Soul or Self or Ego. To Aristotle the Soul in its general aspect is Energy or Essence; and its individual phases are energies. But in the hands of the untrained these conceptions came to be considerably displaced. Essence or Substance came to be understood (as may be seen in Locke, and still more in loose talk) as a something,--a substratum,--or peculiar nature--(of which _in itself_ nothing further could be said(36) but which notwithstanding was permanent and perhaps imperishable): this something subsistent exhibited certain properties or activities. There thus arose, on one hand, the Soul-thing,--a substance misunderstood and sensualised with a supernatural sensuousness,--a denizen of the transcendental or even of the transcendent world: and, on the other hand, stood the actual manifestations, the several exhibitions of this force, the assignable and describable psychic facts. We are accordingly brought before the problem of how this one substance or essence stands to the several entities or hypostases known as faculties. And we still have in the rear the further problem of how these abstract entities stand to the real and concrete single acts and states of soul and mind.