II
THE THOMISTIC THEORY OF INDIVIDUATION
Our problem, then, has been too much neglected. Yet it has indeed had a history. Although Plato considered the matter, Aristotle was the first philosopher who possessed the technical means for fully defining the problem, in all its main aspects, — logical, psychological, and metaphysical. He did define it, — and left it unsolved. The schoolmen, long afterwards, resumed the unfinished task. As the preclassical period of scholasticism was especially busied with the problem of the universal, so the classical and postclassical periods of scholasticism gave great attention to the problem of the individual. Controversy existed, both as to the interpretation of Aristotle’s authority, and as to the independent treatment of those elements of the question which Aristotle had left undecided. In theology, the problem of the Trinity, the problem of the individuality of the “active intelligence” in man, and of the individuality of the human soul itself, in view of its possession of the “active intelligence,” and, finally, the problems of angelology, gave special significance to these scholastic discussions of the Principle of Individuation.
St. Thomas, one of the two principal scholastic students of our problem, decided that form as such, in the Aristotelian sense, is “not to be communicated to various individuals unless by the aid of matter.” This holds, at all events, for the entire created world. In consequence, matter, and in particular
