The category of the general and the special, of the universe and its parts, contains all other categories in the germ. In order to explain the process of thought, we must explain it as a part of the universal process. It has not caused the creation of the world, neither in a theological nor in an idealist sense, nor is it a mere effect of the brain substance, as the materialists of the eighteenth century represented it. The process of thought and its understanding is a peculiarity of the universal cosmos. The relation of the general to the special is the clear and typical category underlying all other categories. One might also apply other names to this category, for instance, the one and the many; the essence and the form; the substance and its attributes; truth and its phenomena, etc. However, a name is but a breath and a sound; understanding and comprehension are what we want in the first place. XII MIND AND MATTER: WHICH IS PRIMARY, WHICH SECONDARY? It is the merit of the philosophical outcome to have delivered the process of understanding from its mystic elements. So long as cause and effect are not recognized as a form of thought belonging to the same species with many other forms of thought, all of which serve the common purpose of illuminating the cosmic processes for the human mind by a symbolized picture composed of various conceptions, just so long will something mysterious adhere to the category of cause and effect. Philosophy is particularly engaged in illuminating the understanding. It has learned enough of its specialty to know that it is a part of the universe performing the special function of arranging the world of phenomena and its smaller circles according to relations of consanguinity and chronology. Such an arrangement presents a scientific picture of the world. The well-known diagram of conceptions used by logicians, consisting of a large circle symbolizing the general, inside of which smaller circles crossing and encircling one another represent the specialties, is a fitting aid in explaining the method by which the faculty of understanding arrives at its scientific results. Science in general is the sum of all special kinds of knowledge, differing from them in no greater degree than the human body from the various organs of which it is composed. A bodily organ can no more exist outside of the body than any particular knowledge can exist outside of the generality of all sciences. No metaphysics is possible under this condition.