The simplest representations are the sensations, which, amid all their variety, still group themselves into definite classes (odors, sounds, colors).  They serve us as symbols of the disturbing reals, but they are not images of things, nor effects of these, but products of the soul itself:  the generation of sensations is the soul’s peculiar way of guarding itself against threatened disturbances.  Every representation once come into being disappears again from consciousness, it is true, but not from the soul.  It persists, unites with others, and stands with them in a relation of interaction—­in both cases according to definite laws.  These original representations are the only ones which the soul produces by its own activity; all other psychical phenomena, feeling, desire, will, attention, memory, judgment, the whole wealth of inner events, result of themselves from the interplay of the primary representations under law.  Representation (more exactly sensation) is alone original; space, time, the categories, which Kant makes a priori, are all acquired, i.e., like all the higher mental life, they are the results of a psychical mechanism, results whose production needs no renewed exertion on the part of the soul itself.  It has been a very harmful error in psychology hitherto to ascribe each particular mental activity to a special faculty of the soul having a similar name, instead of deriving it from combinations of simple representations.  Abstract, empty class ideas have been treated as real forces, in the belief that thus the single concrete acts had been “explained.”

There is no bitterer foe of the faculty theory than Herbart.  His campaign against it, if not victorious, was yet salutary, and the motives of his hostility, up to a certain point, entirely justified.  Nothing is more useless than the assurance that what the soul actually does, that it must also have the power to do.  Who disputes this?  A faculty explains nothing so long as the laws under which its functions and its relations to other faculties remain unexplained.  But although the faculty idea serves no positive end, it cannot be entirely discarded.  It marks the boundary where our ability to reduce one class of psychical phenomena to another ceases.  Herbart’s polemic has no force against the moderate and necessary use of this idea, no matter how much it was in place in view of the impropriety of a superfluous multiplication of the faculties of the soul.  The realization of the ideal of psychology, the reduction of the complex phenomena of mental life to the smallest possible number of simple elements, is limited by the heterogeneity of the original phenomena, knowing, feeling, willing, which wholly resists derivation from the combination of sensations.  That which blinded Herbart to these limitations was that tendency toward unity, which, as a metaphysician and moral philosopher, he had all too willfully suppressed, and which now took revenge for this infringement of its rights by misleading the psychologist to an exaggeration which had important consequences.  Nevertheless his unsuccessful attempt remains interesting and worthy of gratitude.