A Beginner's History of Philosophy, Vol. 2: Modern Philosophy

by Herbert Ernest Cushman

Categories of Relation,—Substance, Cause, Reciprocity.

Categories of Modality,—Possibility, Existence, Necessity.

These categories occupy the same position in the understanding that space and time do in the perception,—they are the a priori principles. In respect to them the perceptions are the a posteriori material. The categories are pure, innate, and transcendental. They are the inner nature of the understanding. Thus the objects of the understanding contain both a priori and a posteriori factors, and are syntheses of manifolds. Perception synthesizes sensations, while the understanding synthesizes perceptions, and states the synthesis in the form of a judgment.

Having named the a priori forms of the understanding, how does Kant show that by their means our knowledge of nature has validity? Because when the understanding functions, it prescribes these forms to perception. Impressions would remain vague and formless, if we did not think them; by means of thought we weld impressions into objects and give them a coherent reality. This is exactly what is meant by understanding. If nature were an independent thing and prescribed laws to the understanding, the laws would never be universal and necessary. The universality ofthe laws of nature can be explained only by supposing that the understanding prescribes its laws to nature, not to nature as a Thing-in-Itself, but only so far as it appears in sense-perception. Universal and necessary knowledge of nature is possible only if the connections and relations of nature are absolutely identical with the modes of thought. The categories of the understanding have objective validity, therefore, because the laws of the understanding are the fundamental laws of nature. The understanding has given such laws to nature. A priori and therefore universal and necessary, synthetic and therefore creative, the world consists of objects under laws of the understanding. There are as many kinds of natural objects as there are categories of the understanding.

If we will examine what we call the world of nature, we shall find that many of its objects have never been perceived. Man has only partly explored the earth, and there are vast regions in space that he has never seen. He has never seen the South Pole, and the North Pole only recently; he has never seen the other side of the moon, and there are myriads of stars beyond even the reach of his telescope. These are not perceptible things, and yet they are the objects of the understanding—objects of knowledge. How is it possible? It would not be possible if the laws of nature were limited to the empirically perceived facts. It is possible because the laws of the understanding are the laws of nature and apply everywhere, whether the thing is actually perceived or not. The moon must have another side because the human understanding conceives all substances in this way; the law of cause and effect obtains beyond the stars, and at the South Pole, even though they have never beenperceived. The world of physical objects, or in other words the world of objects of the understanding, consists of both possible and actually perceived objects. If the laws of nature were prescribed by nature to the mind, then the world of objects would consist only of actually perceived objects.

But look at the world of nature a little more closely. It is one whole world with very many things in it. Why is this the case? Would it ever be so if our knowledge of the world was simply a reproduction of what the world presented to us? Of course not. There would be as many different worlds as there are human beings. The wholeness, the oneness of our world of many things to many individuals indicates not only that the understanding is the source of the laws of the world, but also that the faculties of understanding in all the millions of human beings have a transcendental unity. Knowledge has therefore a stronger proof of its validity, since what is knowledge for one human being is knowledge for all. Every individual man is conscious of the contrast between his own subjective world and the world of knowledge which he shares with other men. His own ideas have a movement of their own and have no validity beyond themselves; the ideas which he shares with others, however, are valid for all others because these ideas are beyond the control of any one man. Each individual man has to acknowledge this control of his knowledge as residing in something beyond himself. The categories of each man’s understanding coöperate exactly with those of every other man. The individual man is not actually conscious of this process of coöperation in experience, but he accepts the objective necessity of it.

The individual consciousness is not therefore thecreator of the objects of knowledge; rather consciousness in general—the consciousness of humanity—is the creator. Kant is not a solipsist, but an idealist. A higher consciousness, a super-conscious Self, must be assumed to explain the compactness of human knowledge. Kant does not call this super-conscious Self the “soul” or “spirit,” but the “I think” or the “transcendental ego,” or by the more clumsy phrase “the transcendental unity of apperception.” He contrasts it with what he calls the “empirical ego” on the ground that it is the ego always identical with itself, rather than the Self at this or that particular moment. It is the Self as thinker rather than the Self as thought about. The super-conscious Self is always self-active and never dependent upon empirical conditions. It must be accepted as the postulate of all knowledge. It is the universal Self, and through it the categories of the human understanding become universalized. Just as space and time are the unifying forms of synthetic consciousness on its lower level; just as the categories of the understanding are the unifying forms of the synthetic consciousness on a higher level; so the universal Self must be postulated to explain the universality of the categories. It is a postulate only because it, not known in experience, is necessary to explain the unity of knowledge. This theoretical conception of the Self by Kant is thus very different from the traditional notion of the soul.

Has the Reason by Itself any Validity? When Kant calls his criticism the Critique of Pure Reason, he uses the term “Reason” in a wide sense as the whole knowing process. In the Dialectic he treats the Reason in a narrow sense, as if it were a special faculty like the perception or understanding. This is, of course, a confusinguse of terms, like his use of the term “Synthesis”; but it should cause no difficulty provided the two uses are known beforehand. The term “Ideas” is also used in two senses. In this place it has a special use. While usually an idea means any thought, here it means the synthetic form of the special faculty of the reason, just as the categories are the form of the understanding, and space and time the form of sense-perception. The synthetic forms of the Reason are the three Ideas, viz., God, the soul, and the totality of the universe.

What is the office of this special faculty of the Reason and its Idea-forms? They represent Kant’s way of stating the natural tendency of the human mind to get from its knowledge the greatest possible unity with the greatest possible extension. Consciousness is a synthesis which is never satisfied in being partial and incomplete. The partial syntheses of its faculties of perception and understanding do not satisfy it. Perception and understanding tell us nothing about God, about the soul, and about the totality of the universe, for these faculties are fettered to experience. Yet God, the soul, and the totality of the universe are very important matters. So the Reason leaps over the boundaries of experience, and thinks it is justified in poaching in the territory forbidden to knowledge. The Reason is not content with the partial and relational knowledge of mathematics and of physical science, but it would deal with the unrelated and the unconditioned. Indeed, we need only search our own minds to see how true Kant is to fact. We find that we ourselves are not satisfied with conditioned things, which must be explained by other conditioned things. On the contrary, we long to know the absolutely unconditioned, which alone will explain all conditions.We are forever seeking to make our synthesis complete, and to render a rational and complete account of what is nevertheless impossible to our knowledge.

Now it is evident that the Ideas of the Reason are not indispensable to knowledge in the sense that the categories of the understanding and the forms of sense perception are indispensable. Cause, time, and space enter into all knowledge. Physical and mathematical laws exist as facts, and need no proof for their existence. Kant asked about them, “How are synthetic a priori judgments possible?” But concerning the judgments of the Reason, he asks a different question: not How are they possible, but Are they possible?