Critique of Pure Reason

by Immanuel Kant

  On the side of empiricism, so far as it determines the cosmological ideas, or the antithesis, there is:—

  First, No such practical interest, arising from the pure principles of reason, as morality and religion possess. On the contrary, empiricism seems to deprive both of their power and influence. If there is no original Being, different from the world; if the world is without a beginning, and therefore without a Creator; if our will is not free, and our soul shares the same divisibility and perishableness with matter, moral ideas also and principles lose all validity, and fall with the transcendental ideas, which formed their theoretic support.

  But, on the other side, empiricism offers advantages to the speculative interests of reason, which are very tempting, and far exceed those which the dogmatical teacher can promise. With the empiricist the understanding is always on its own proper ground, namely, the field of all possible experience, the laws of which may be investigated and serve to enlarge certain and intelligible knowledge without end. Here every object can and ought to be represented to intuition, both in itself and in its relations, or at least in concepts, the images of which can be clearly and distinctly represented in given similar intuitions. Not only is there no necessity for leaving the chain of the order of nature in order to lay hold of ideas, the objects of which are not known, because, as mere products of thought, they can never be given, but the understanding is not even allowed to leave its proper business and, under pretence of its being finished, to cross into the domain of idealising reason and transcendental concepts, where it need no longer observe and investigate according to the laws of nature, but only think and dream, without any risk of being contradicted by the facts of nature, not being bound by their evidence, but justified in passing them by, or in even subordinating them to a higher authority, namely, that of pure reason.

  Hence the empiricist will never allow that any epoch of nature should be considered as the absolutely first, or any limit of his vision into the extent of nature should be considered as the last. He will not approve of a transition from the objects of nature, which he can analyse by observation and mathematics and determine synthetically in intuition (the extended), to those which neither sense nor imagination can ever represent in concreto (the simple); nor will he concede that a faculty be presupposed, even in nature, to act independent of the laws of nature (freedom), thus narrowing the operations of the understanding in investigating, according to the necessary rules, the origin of phenomena. Lastly, he will never tolerate that the cause of anything should be looked for anywhere outside of nature (in the original Being), because we know nothing but nature, which alone can offer us objects and instruct us as to their laws.

  If the empirical philosopher had no other purpose with his antithesis but to put down the rashness and presumption of reason in mistaking her true purpose, while boasting of insight and knowledge, where insight and knowledge come to an end, nay, while representing, what might have been allowed to pass on account of practical interests, as a real advancement of speculative enquiry, in order, when it is so disposed, either to tear the thread of physical enquiry, or to fasten it, under the pretence of enlarging our knowledge, to those transcendental ideas, which really teach us only that we know nothing; if, I say, the empiricist were satisfied with this, then his principle would only serve to teach moderation in claims, modesty in assertions, and encourage the greatest possible enlargement of our understanding through the true teacher given to us, namely, experience. For in such a case we should not be deprived of our own intellectual presumptions or of our faith in their influence on our practical interests. They would only have lost the pompous titles of science and rational insight, because true speculative knowledge can never have any other object but experience; and, if we transcend its limits, our synthesis, which attempts new kinds of knowledge independent of experience, lacks that substratum of intuition to which alone it could be applied.

  As it is, empiricism becomes often itself dogmatical with regard to ideas, and boldly denies what goes beyond the sphere of its intuitive knowledge, and thus becomes guilty itself of a want of modesty, which here is all the more reprehensible, because an irreparable injury is thereby inflicted on the practical interests of reason.

  This constitutes the opposition of Epicureanism13 to Platonism.

  Either party says more than it knows; but, while the former encourages and advances knowledge, although at the expense of practical interests, the latter supplies excellent practical principles, but with regard to everything of which speculative knowledge is open to us, it allows reason to indulge in ideal explanations of natural phenomena and to neglect physical investigation.

  With regard to the third point which has to be considered in a preliminary choice between the two opposite parties, it is very strange that empiricism should be so unpopular, though it might be supposed that the common understanding would readily accept a theory which promises to satisfy it by experimental knowledge and its rational connection, while transcendental dogmatism forces it to ascend to concepts which far surpass the insight and rational faculties of the most practised thinkers. But here is the real motive;—the man of ordinary understanding is so placed thereby that even the most learned can claim no advantage over him. If he knows little or nothing, no one can boast of knowing much more, and though he may not be able to employ such scholastic terms as others, he can argue and subtilise infinitely more, because he moves about among mere ideas, about which it is easy to be eloquent, because no one knows anything about them. The same person would have to be entirely silent, or would have to confess his ignorance with regard to scientific enquiries into nature. Indolence, therefore, and vanity are strongly in favour of those principles. Besides, although a true philosopher finds it extremely hard to accept the principle of which he can give no reasonable account, still more to introduce concepts the objective reality of which cannot be established, nothing comes more natural to the common understanding that wants something with which it can operate securely. The difficulty of comprehending such a supposition does not disquiet a person of common understanding, because not knowing what comprehending really means, it never enters into his mind, and he takes everything for known that has become familiar to him by frequent use. At last all speculative interest disappears before the practical, and he imagines that he understands and knows what his fears and hopes impel him to accept or to believe. Thus the empiricism of a transcendentally idealising reason loses all popularity and, however prejudicial it may be to the highest practical principles, there is no reason to fear that it will ever pass the limits of the school and obtain in the commonwealth any considerable authority, or any favour with the multitude.

  Human reason is by its nature architectonic, and looks upon all knowledge as belonging to a possible system. It therefore allows such principles only which do not render existing knowledge incapable of being associated with other knowledge in some kind of system. The propositions of the antithesis, however, are of such a character that they render the completion of any system of knowledge quite impossible. According to them there is always beyond every state of the world, an older state; in every part, other and again divisible parts; before every event, another event which again is produced from elsewhere, and everything in existence is conditioned, without an unconditioned and first existence anywhere. As therefore the antithesis allows of nothing that is first, and of no beginning which could serve as the foundation of an edifice, such an edifice of knowledge is entirely impossible with such premisses. Hence the architectonic interest of reason (which demands not empirical, but pure rational unity a priori) serves as a natural recommendation of the propositions of the thesis.

  But if men could free themselves from all such interests, and consider the assertions of reason, unconcerned about their consequences, according to the value of their arguments only, they would find themselves, if they knew of no escape from the press except adhesion to one or the other of the opposite doctrines, in a state of constant oscillation. To-da
y they would be convinced that the human will is free; to-morrow, when considering the indissoluble chain of nature, they would think that freedom is nothing but self-deception, and nature all in all. When afterwards they come to act, this play of purely speculative reason would vanish like the shadows of a dream, and they would choose their principles according to practical interests only. But, as it well befits a reflecting and enquiring being to devote a certain time entirely to the examination of his own reason, divesting himself of all partiality, and then to publish his observations for the judgment of others, no one ought to be blamed, still less be prevented, if he wishes to produce the thesis as well as the antithesis, so that they may defend themselves, terrified by no menace, before a jury of his peers, that is, before a jury of weak mortals.

  The Antinomy of Pure Reason

  Section IV

  Of the Transcendental Problems of Pure Reason, and the Absolute Necessity of their Solution

  To attempt to solve all problems, and answer all questions, would be impudent boasting, and so extravagant a self-conceit, that it would forfeit all confidence. Nevertheless there are sciences the very nature of which requires that every question which can occur in them should be answerable at once from what is known, because the answer must arise from the same sources from which the question springs. Here it is not allowed to plead inevitable ignorance, but a solution can be demanded. We must be able, for instance, to know, according to a rule, what in every possible case is right or wrong, because this touches our obligation, and we cannot have any obligation to that which we cannot know. In the explanation, however, of the phenomena of nature, many things must remain uncertain, and many a question insoluble, because what we know of nature is by no means sufficient, in all cases, to explain what has to be explained. It has now to be considered, whether there exists in transcendental philosophy any question relating to any object of reason which, by that pure reason, is unanswerable, and whether we have a right to decline its decisive answer by treating the object as absolutely uncertain (from all that we are able to know), and as belonging to that class of objects of which we may form a sufficient conception for starting a question, without having the power or means of ever answering it.

  Now I maintain that transcendental philosophy has this peculiarity among all speculative knowledge, that no question, referring to an object of pure reason, can be insoluble for the same human reason; and that no excuse of inevitable ignorance on our side, or of unfathomable depth on the side of the problem, can release us from the obligation to answer it thoroughly and completely; because the same concept, which enables us to ask the question, must qualify us to answer it, considering that, as in the case of right and wrong, the object itself does not exist, except in the concept.

  There are, however, in transcendental philosophy no other questions but the cosmological, with regard to which we have a right to demand a satisfactory answer, touching the quality of the object; nor is the philosopher allowed here to decline an answer by pleading impenetrable obscurity. These questions can refer to cosmological ideas only, because the object must be given empirically, and the question only refers to the adequateness of it to an idea. If the object is transcendental and therefore itself unknown, as, for instance, whether that something the phenomenal appearance of which (within ourselves) is the thinking (soul), be in itself a simple being, whether there be an absolutely necessary cause of all things, etc., we are asked to find an object for our idea of which we may well confess that it is unknown to us, though not therefore impossible.14 The cosmological ideas alone possess this peculiarity that they may presuppose their object, and the empirical synthesis required for the object, as given, and the question which they suggest refers only to the progress of that synthesis, so far as it is to contain absolute totality, such absolute totality being no longer empirical, because it cannot be given in any experience. As we are here concerned solely with a thing, as an object of possible experience, not as a thing by itself, it is impossible that the answer of the transcendent cosmological question can be anywhere but in the idea, because it refers to no object by itself; and in respect to possible experience we do not ask for that which can be given in concreto in any experience, but for that which lies in the idea, to which the empirical synthesis can no more than approach. Hence that question can be solved from the idea only, and being a mere creation of reason, reason cannot decline her responsibility and put it on the unknown object.

  It is in reality not so strange as it may seem at first, that a science should demand and expect definite answers to all the questions belonging to it (quaestiones domesticae), although at present these answers have not yet been discovered. There are, in addition to transcendental philosophy, two other sciences of pure reason, the one speculative, the other practical, pure mathematics, and pure ethics. Has it ever been alleged that, it may be on account of our necessary ignorance of the conditions, it must remain uncertain what exact relation the diameter bears to a circle, in rational or irrational numbers? As by the former the relation cannot be expressed adequately, and by the latter has not yet been discovered, it was judged rightly that the impossibility at least of the solution of such a problem can be known with certainty, and Lambert gave even a demonstration of this. In the general principles of morality there can be nothing uncertain, because its maxims are either entirely null and void, or derived from our own rational concepts only. In natural science, on the contrary, we have an infinity of conjectures with regard to which certainty can never be expected, because natural phenomena are objects given to us independent of our concepts, and the key to them cannot be found within our own mind, but in the world outside us. For that reason it cannot in many cases be found at all, and a satisfactory answer must not be expected. The questions of the transcendental Analytic, referring to the deduction of our pure knowledge, do not belong to this class, because we are treating at present of the certainty of judgments with reference to their objects only, and not with reference to the origin of our concepts themselves.

  We shall not, therefore, be justified in evading the obligation of a critical solution, at least of the questions of reason, by complaints on the narrow limits of our reason, and by confessing, under the veil of humble self-knowledge, that it goes beyond the powers of our reason to determine whether the world has existed from eternity, or has had a beginning; whether cosmical space is filled with beings ad infinitum, or enclosed within certain limits; whether anything in the world is simple, or everything can be infinitely divided; lastly, whether there is a Being entirely unconditioned and necessary in itself, or whether the existence of everything is conditioned, and therefore externally dependent, and in itself contingent. For all these questions refer to an object which can be found nowhere except in our own thoughts, namely, the absolutely unconditioned totality of the synthesis of phenomena. If we are not able to say and establish anything certain about this from our own concepts, we must not throw the blame on the object itself as obscure, because such an object (being nowhere to be found, except in our ideas) can never be given to us; but we must look for the real cause of obscurity in our idea itself, which is a problem admitting of no solution, though we insist obstinately that a real object must correspond to it. A clear explanation of the dialectic within our own concept, would soon show us, with perfect certainty, how we ought to judge with reference to such a question.

  If people put forward a pretext of being unable to arrive at certainty with regard to these problems, the first question which we ought to address to them, and which they ought to answer clearly, is this, Whence do you get those ideas, the solution of which involves you in such difficulty? Are they phenomena, of which you require an explanation, and of which you have only to find, in accordance with those ideas, the principles, or the rule of their explanation? Suppose the whole of nature were spread out before you, and nothing were hid to your senses and to the consciousness of all that is presented to your intuition, yet you would never be able to know by one single experience th
e object of your ideas in concreto (because, in addition to that complete intuition, what is required is a completed synthesis, and the consciousness of its absolute totality, which is impossible by any empirical knowledge). Hence your question can never be provoked for the sake of explaining any given phenomenon, and as it were suggested by the object itself. Such an object can never come before you, because it can never be given by any possible experience. In all possible perceptions you always remain under the sway of conditions, whether in space or in time; you never come face to face with anything unconditioned, in order thus to determine whether the unconditioned exists in an absolute beginning of the synthesis, or in an absolute totality of the series without any beginning. The whole, in its empirical meaning, is always relative only. The absolute whole of quantity (the universe), of division, of origination, and of the condition of existence in general, with all the attendant questions as to whether it can be realised by a finite synthesis or by a synthesis to be carried on ad infinitum, has nothing to do with any possible experience. You would, for instance, never be able to explain the phenomena of a body in the least better, or even differently, whether you assume that it consists of simple or throughout of composite parts: for neither a simple phenomenon, nor an infinite composition can ever meet your senses. Phenomena require to be explained so far only as the conditions of their explanation are given in perception; but whatever may exist in them, if comprehended as an absolute whole, can15 never be a perception. Yet it is this very whole the explanation of which is required in the transcendental problems of reason.