IMMANUEL KANT

The Critique of Pure Reason

Immanuel Kant, the most celebrated of German metaphysicians, was born at Konigsberg on April 22, 1724, and died on February 12, 1804. Taking his degree at Konigsberg, he speedily entered on a professional career, which he quietly and strenuously pursued for over thirty years. Though his lectures were limited to the topics with which he was concerned as professor of logic and philosophy, his versatility is evidenced by the fact that he was offered the chair of poetry, which he declined. His lasting reputation began with the publication, in 1781, of his wonderful "Critique of Pure Reason" ("Kritik der reinen Vernunft"). Within twelve years of its appearance it was expounded in all the leading universities, and even penetrated into the schools of the Church of Rome. Kant was the first European thinker who definitely grasped the conception of a critical philosophy, though he was doubtless aided by the tendency of Locke"s psychology. He did much to counteract the sceptical influence of Hume. The main object of his "Critique of Pure Reason" is to separate the necessary and universal in the realm of knowledge from the merely experimental or empirical. This little version of Kant"s celebrated work has been prepared from the German text.

_I.--Knowledge Transcendental: aesthetic_

Experience is something of which we are conscious. It is the first result of our comprehension, but it is not the limit of our understanding, since it stimulates our faculty of reason, but does not satisfy its desire for knowledge. While all our knowledge may begin with sensible impressions or experience, there is an element in it which does not rise from this source, but transcends it. That knowledge is transcendental which is occupied not so much with mere outward objects as with our manner of knowing those objects, that is to say, with our _a priori_ concepts of them. All our knowledge is either _a priori_ or _a posteriori_. That is _a posteriori_ knowledge which is derived from sensible experience as including sensible impressions or states; while _a priori_ knowledge is that which is not thus gained, but consists of whatever is universal or necessary. A complete "Transcendental Philosophy" would be a systematic exposition of all that is _a priori_ in human knowledge, or of "all the principles of pure reason." But a "Critique of Pure Reason" cannot include all this. It can do little more than deal with the synthetic element or quality in _a priori_ knowledge, as distinguished from the a.n.a.lytic element.

We perceive objects through our sensibility which furnishes us, as our faculty of receptivity, with those intuitions that become translated into thought by means of the understanding. This is the origin of our conceptions, or ideas. I denominate as _matter_ that which in a phenomenon corresponds to sensation; while I call _form_ that quality of matter which presents it in a perceived order. Only matter is presented to our minds _a posteriori_; as to form, this must inevitably exist in the mind _a priori_, and therefore it can be considered apart from all sensation.

Pure representation, entirely apart from sensation, in a transcendental signification, forms the pure intuition of the mind, existing in it as a mere form of sensibility. Transcendental aesthetic is the science of all the principles of sensibility. But transcendental logic is the science of the principles of pure thought. In studying the former we shall find that there are two pure forms of sensuous intuition, namely, s.p.a.ce and time.

Are s.p.a.ce and time actual ent.i.ties? Or are they only relations of things? s.p.a.ce is simply the form of all the phenomena of external senses; that is, it is the subjective condition of the sensibility under which alone external intuition is possible. Thus, the form of all phenomena may exist _a priori_ in the soul as a pure intuition previous to all experience. So we can only speak of s.p.a.ce and of extended objects from the standpoint of human reason. But when we have abstracted all the forms perceived by our sensibility, there remains a pure intuition which we call s.p.a.ce. Therefore our discussion teaches us the objective validity of s.p.a.ce with regard to all that can appear before us externally as an object; but equally the subjective ideality of s.p.a.ce, with regard to things if they are considered in themselves by our reason, that is, without taking into account the nature of our sensibility.

Time is not empirically conceived of; that is, it is not experimentally apprehended. Time is a necessary representation on which all intuitions are dependent, and the representation of time to the mind is thus given _a priori._ In it alone can phenomena be apprehended. These may vanish, but time cannot be put aside.

Time is not something existing by itself independently, but is the formal condition _a priori_ of all phenomena. If we deduct our own peculiar sensibility, then the idea of time disappears indeed, because it is not inherent in any object, but only in the subject which perceives that object. s.p.a.ce and time are essential _a priori_ ideas, and they are the necessary conditions of all particular perceptions.

From the latter and their objects we can, in imagination, without exception, abstract; from the former we cannot.

s.p.a.ce and time are therefore to be regarded as the necessary _a priori_ pre-conditions of the possibility and reality of all phenomena. It is clear that transcendental aesthetic can obtain only these two elements, s.p.a.ce and time, because all other concepts belong to the senses and pre-suppose experience, and so imply something empirical. For example, the concept of motion pre-supposes something moving, but in s.p.a.ce regarded alone there is nothing that moves; therefore, whatever moves must be recognised by experience, and is a purely empirical datum.

_II.--Transcendental Logic_

Our knowledge is derived from two fundamental sources of the consciousness. The first is the faculty of receptivity of impressions; the second, the faculty of cognition of an object by means of these impressions or representations, this second power being sometimes styled spontaneity of concepts. By the first, an object is given to us; by the second it is thought of in the mind. Thus intuition and concepts const.i.tute the elements of our entire knowledge, for neither intuition without concepts, nor concepts without intuition, can yield any knowledge whatever. Hence arise two branches of science, aesthetic and logic, the former being the science of the rules of sensibility; the latter, the science of the rules of the understanding.

Logic can be treated in two directions: either as logic of the general use of the understanding, or of some particular use of it. The former includes the rules of thought, without which there can be no use of the understanding; but it has no regard to the objects to which the understanding is applied. This is elementary logic. But logic of the understanding in some particular use includes rules of correct thought in relation to special cla.s.ses of objects; and this latter logic is generally taught in schools as preliminary to the study of sciences.

Thus, general logic takes no account of any of the contents of knowledge, but is limited simply to the consideration of the forms of thought. But we are constrained by antic.i.p.ation to form an idea of a logical science which has to deal not only with pure thought, but also has to determine the origin, validity, and extent of the knowledge to which intuitions relate, and this science might be styled transcendental logic.

In transcendental aesthetic we isolated the faculty of sensibility. So in transcendental logic we isolate the understanding, concentrating our consideration on that element of thought which has its source simply in the understanding. But transcendental logic must be divided into transcendental a.n.a.lytic and transcendental dialectic. The former is a logic of truth, and is intended to furnish a canon of criticism. When logic is used to judge not a.n.a.lytically, but to judge synthetically of objects in general, it is called transcendental dialectic, which serves as a protection against sophistical fallacy.

a.n.a.lYTIC OF PURE CONCEPTS

The understanding may be defined as the faculty of judging. The function of thought in a judgment can be brought under four heads, each with three subdivisions.

1. Quant.i.ty of judgments: Universal, particular, singular.

2. Quality: Affirmative, negative, infinite.

3. Relation: Categorical, hypothetical, disjunctive.

4. Modality: Problematical, a.s.sertory, apodictic [above contradiction].

If we examine each of these forms of judgment we discover that in every one is involved some peculiar idea which is its essential characteristic. Thus, a singular judgment, in which the subject of discourse is a single object, involves obviously the special idea of oneness, or unity. A particular judgment, relating to several objects, implies the idea of plurality, and discriminates between the several objects. Now, the whole list of these ideas will const.i.tute the complete cla.s.sification of the fundamental conceptions of the understanding, regarded as the faculty which judges, and these may be called categories.

1. Of Quant.i.ty: Unity, plurality, totality.

2. Of Quality: Reality, negation, limitation.

3. Of Relation: Substance and accident, cause and effect, action and reaction.

4. Of Modality: Possibility--impossibility, existence--non-existence, necessity--contingence.

These, then, are the fundamental, primary, or native conceptions of the understanding, which flow from, or const.i.tute the mechanism of, its nature; are inseparable from its activity; and are hence, for human thought, universal and necessary, or _a priori_. These categories are "pure" conceptions of the understanding, inasmuch as they are independent of all that is contingent in sense.

TRANSCENDENTAL DIALECTIC

A distinction is usually made between what is immediately known and what is only inferred. It is immediately known that in a figure bounded by three straight lines there are three angles, but that these angles together are equal to two right angles is only inferred. In every syllogism is first a fundamental proposition; secondly, another deduced from it; and, thirdly, the consequence.

In the use of pure reason its concepts, or transcendental ideas, aim at unity of all conditions of thought. So all transcendental ideas may be arranged in three cla.s.ses; the first containing the unity of the thinking subject; the second, the unity of the conditions of phenomena observed; the third, the unity of the objective conditions of thought.

This cla.s.sification becomes clear if we note that the thinking subject is the object-matter of psychology; while the system of all phenomena (the world) is the object-matter of cosmology; and the Being of all Beings (G.o.d) is the object-matter of theology.

Hence we perceive that pure reason supplies three transcendental ideas, namely, the idea of a transcendental science of the soul (_psychologia rationalis_); of a transcendental science of the world (_cosmologia rationalis_); and, lastly, of a transcendental science of G.o.d (_theologia transcendentalis_). It is the glory of transcendental idealism that by it the mind ascends in the series of conditions till it reaches the unconditioned, that is, the principles. We thus progress from our knowledge of self to a knowledge of the world, and through it to a knowledge of the Supreme Being.

_III.--The Antinomies of Pure Reason_

Transcendental reason attempts to reconcile conflicting a.s.sertions.

There are four of these antinomies, or conflicts.

FIRST ANTINOMY. Thesis. The world has a beginning in time, and is also limited in regard to s.p.a.ce. Proof. Were the world without a time-beginning we should have to ascribe a present limit to that which can have no limit, which is absurd. Again, were the world not limited in regard to s.p.a.ce, it must be conceived as an infinite whole, yet it is impossible thus to conceive it.

Ant.i.thesis. The world has neither beginning in time, nor limit in s.p.a.ce, but in both regards is infinite. Proof. The world must have existed from eternity, or it could never exist at all. If we imagine it had a beginning, we must imagine an anterior time when nothing was. But in such time the origin of anything is impossible. At no moment could any cause for such a beginning exist.

SECOND ANTINOMY. Thesis. Every composite substance in the world is composed of simple parts. This thesis seems scarcely to require proof.

No one can deny that a composite substance consists of parts, and that these parts, if themselves composite, must consist of others less composite, till at length we come, by compulsion of thought, to the conception of the absolutely simple as that wherein the substantial consists.

Ant.i.thesis. No composite thing in the world consists of simple parts, and nothing simple exists anywhere in the world. Proof. Each simple part implied in the thesis must be in s.p.a.ce. But this condition is a positive disproof of their possibility. A simple substance would have to occupy a simple portion of s.p.a.ce; but s.p.a.ce has no simple parts. The supposition of such a part is the supposition, not of s.p.a.ce, but of the negation of s.p.a.ce. A simple substance, in existing and occupying any portion of s.p.a.ce, must contain a real multiplicity of parts external to each other, _i.e._, it must contradict its own nature, which is absurd.

THIRD ANTINOMY. Thesis. The causality of natural law is insufficient for the explanation of all the phenomena of the universe. For this end another kind of causality must be a.s.sumed, whose attribute is freedom.

Proof. All so-called natural causes are effects of preceding causes, forming a regressive series of indefinite extent, with no first beginning. So we never arrive at an adequate cause of any phenomenon.

Yet natural law has for its central demand that nothing shall happen without such a cause.

Ant.i.thesis. All events in the universe occur under the exclusive operation of natural laws, and there is no such thing as freedom. Proof.

The idea of a free cause is an absurdity. For it contradicts the very law of causation itself, which demands that every event shall be in orderly sequence with some preceding event. Now, free causation is such an event, being the active beginning of a series of phenomena. Yet the action of the supposed free cause must be imagined as independent of all connection with any previous event. It is without law or reason, and would be the blind realisation of confusion and lawlessness. Therefore transcendental freedom is a violation of the law of causation, and is in conflict with all experience. We must of necessity acquiesce in the explanation of all phenomena by the operation of natural law, and thus transcendental freedom must be p.r.o.nounced a fallacy.

FOURTH ANTINOMY. Thesis. Some form of absolutely necessary existence belongs to the world, whether as its part or as its cause. Proof.

Phenomenal existence is serial, mutable, consistent. Every event is contingent upon a preceding condition. The conditioned pre-supposes, for its complete explanation, the unconditioned. The whole of past time, since it contains the whole of all past conditions, must of necessity contain the unconditioned or also "absolutely necessary."

Ant.i.thesis. There is no absolutely necessary existence, whether in the world as its part, or outside of it as its cause. Proof. Of unconditionally necessary existence within the world there can be none.

The a.s.sumption of a first unconditioned link in the chain of cosmical conditions is self-contradictory. For such link or cause, being in time, must be subject to the law of all temporal existence, and so be determined--contrary to the original a.s.sumption--by another link or cause before it.