PART III
THE PRINCIPLE OF INDIVIDUATION
The question: What is an individual? and the related question: What principle is the source of Individuation, or of the presence and variety of individuals in the world, or in our knowledge? — these are matters of no small importance for logic, for psychology, and for metaphysics. All these three doctrines have to do with individuals, as possible objects of thought, as well as with those other logical objects called universals. The psychologist has to ask the question: How do we come by the knowledge of the individual objects? — whether primarily or by some secondary process, and whether solely through experience or by virtue of some reflective or intuitive insight. The metaphysician is above all concerned with the questions: What sort of individuals does the real world contain? and, How are they distinguished from one another and from the other types of reality which the universe contains, if there are such other types? The present division of this paper has something to say of all three aspects of our problem; and, as a fact, all three aspects are obviously closely related to one another.
I
DEFINITION OF THE PROBLEM
As to the general interest of the problem, even outside of technical philosophy, there can be no
