Critique of Pure Reason

by Immanuel Kant

  But after practical reason has reached this high point, namely, the concept of a sole original Being as the supreme good, it must not imagine that it has raised itself above all empirical traditions of its application and soared up to an immediate knowledge of new objects, and thus venture to start from that concept and to deduce from it the moral laws themselves. For it was these very laws the internal practical necessity of which led us to the admission of an independent cause, or of a wise ruler of the world that should give effect to them. We ought not, therefore, to consider them afterwards again as accidental and derived from the mere will of the ruler, particularly as we could have no concept of such a will, if we had not formed it in accordance with those laws. So far as practical reason is entitled to lead us we shall not look upon actions as obligatory because they are the commands of God, but look upon them as divine commands because we feel an inner obligation to follow them. We shall study freedom according to the unity of design determined by the principles of reason, and we shall believe ourselves to be acting in accordance with the Divine will in so far only as we hold sacred the moral law which reason teaches us from the nature of actions themselves. We shall believe ourselves to be serving Him only by promoting everything that is best in the world, both in ourselves and in others. Moral theology is, therefore, of immanent use only, teaching us to fulfil our destiny here in the world by adapting ourselves to the general system of ends, without either fanatically or even criminally abandoning the guidance of reason and her moral laws for our proper conduct in life, in order to connect it directly with the idea of the Supreme Being. This would be a transcendent use of moral theology which, like a transcendent use of mere speculation, must inevitably pervert and frustrate the ultimate aims of reason.

  Canon of Pure Reason

  Section III

  Of Trowing, Knowing, and Believing

  The holding a thing to be true is an event in our understanding which, though it may rest on objective grounds, requires also subjective causes in the mind of the person who is to judge. If the judgment is valid for everybody, if only he is possessed of reason, then the ground of it is objectively sufficient, and the holding it to be true is called conviction. If, on the contrary, it has its ground in the peculiar character of the subject only, it is called persuasion.

  Persuasion is a mere illusion, the ground of the judgment, though it lies solely in the subject, being regarded as objective. Such a judgment has, therefore, private validity only, and the holding it to be true cannot be communicated to others. Truth, however, depends on agreement with the object, and, with regard to it, the judgments of every understanding must agree with each other (consentientia uni tertio consentiunt inter se, etc.). An external criterion, therefore, as to whether our holding a thing to be true be conviction or only persuasion, consists in the possibility of communicating it, and finding its truth to be valid for the reason of every man. For, in that case, there is at least a presumption that the ground of the agreement of all judgments, in spite of the diversity of the subjects, rests upon the common ground, namely, on the object with which they all agree, and thus prove the truth of the judgment.

  Persuasion, therefore, cannot be distinguished from conviction, subjectively, so long as the subject views its judgment as a phenomenon of his own mind only; the experiment, however, which we make with the grounds that seem valid to us, by trying to find out whether they will produce the same effect on the reason of others, is a means, though only a subjective means, not indeed of producing conviction, but of detecting the merely private validity of the judgment, that is, of discovering in it what is merely persuasion.

  If we are able besides to analyse the subjective causes of our judgment, which we have taken for its objective grounds, and thus explain the deceptive judgment as a phenomenon in our mind, without having recourse to the object itself, we expose the illusion and are no longer deceived by it, although we may continue to be tempted by it, in a certain degree, if, namely, the subjective cause of the illusion is inherent in our nature.

  I cannot maintain anything, that is, affirm it as a judgment necessarily valid for everybody, except it work conviction. Persuasion I may keep for myself, if it is agreeable to me, but I cannot, and ought not to attempt to make it binding on any but myself.

  The holding anything to be true, or the subjective validity of a judgment admits, with reference to the conviction which is at the same time valid objectively, of the three following degrees, throwing, believing, knowing. Throwing is to hold true, with the consciousness that it is insufficient both subjectively and objectively. If the holding true is sufficient subjectively, but is held to be insufficient objectively, it is called believing; while, if it is sufficient both subjectively and objectively, it is called knowing. Subjective sufficiency is called conviction (for myself), objective sufficiency is called certainty (for everybody). I shall not dwell any longer on the explanation of such easy concepts.

  I must never venture to trow, or to be of opinion, without knowing at least something by means of which a judgment, problematical by itself, is connected with truth, which connection, though it involves not a complete truth, is yet attended with more than arbitrary fiction. Moreover, the law of such a connection must be certain. For if, even with regard to this law, I should have nothing but an opinion, all would become a mere play of the imagination, without the least relation to truth.

  In the judgments of pure reason opinion is not permitted. For, as they are not based on empirical grounds, but everything has to be known a priori, and everything therefore must be necessary, the principle of connection in them requires universality and necessity, and consequently perfect certainty, without which there would be nothing to lead us on to truth. Hence it is absurd to have an opinion in pure mathematics; here one must either know, or abstain from pronouncing any judgment. The same applies to the principles of morality, because one must not hazard an action on the mere opinion that it is allowed, but must know it to be so.

  In the transcendental employment of reason, on the contrary, mere opinion, no doubt, would be too little, but knowledge too much. Speculatively, therefore, we cannot here form any judgment at all, because the subjective grounds on which we hold a thing to be true, as for instance those which may very well produce belief, are not approved of in speculative questions, as they cannot be held without empirical support, nor, if communicated to others, can produce the same effect on them.

  Nor can the theoretically insufficient acceptance of truth be called belief, except from a practical point of view. And this practical view refers either to skill or to morality, the former being concerned with any contingent and casual ends and objects whatsoever, the latter with absolutely necessary ends only.

  If we have once proposed an object or end to ourselves, the conditions of attaining it are hypothetically necessary. This necessity is subjective, and yet but relatively sufficient, if I know of no other conditions under which the end can be attained: it is sufficient absolutely and for every one, if I am convinced that no one can know of other conditions, leading to the attainment of our end. In the former case my assuming and holding certain conditions as true is merely an accidental belief, while in the latter case it is a necessary belief. Thus a physician, for instance, may feel that he must do something for a patient, who is in danger. But as he does not know the nature of the illness, he observes the symptoms, and arrives at the conclusion, as he knows nothing else, that it is phthisis. His belief, according to his own judgment, is contingent only, and he knows that another might form a better judgment. It is this kind of contingent belief which, nevertheless, supplies a ground for the actual employment of means to certain actions, which I call pragmatic belief.

  The usual test, whether something that is maintained be merely persuasion, or a subjective conviction at least, that is, firm belief, is betting. People often pronounce their views with such bold and uncompromising assurance that they seem to have abandoned all fear of error. A bet startles them. Sometimes it t
urns out that a man has persuasion sufficient to be valued at one ducat, but not at ten; he is ready to venture the first ducat, but with ten, he becomes aware for the first time that, after all, it might be possible that he should be mistaken. If we imagine that we have to stake the happiness of our whole life, the triumphant air of our judgment drops considerably; we become extremely shy, and suddenly discover that our belief does not reach so far. Thus pragmatic belief admits of degrees which, according to the difference of the interests at stake, may be large or small.

  Now it is true, no doubt, that, though with reference to an object of our belief, we can do nothing, and our opinion is, therefore, purely theoretical, yet in many cases we can represent and imagine to ourselves an undertaking for which we might think that we had sufficient inducements, if any means existed of ascertaining the truth of the matter. Thus, even in purely theoretical judgments, there is an analogon of practical judgments to which the word belief may be applied, and which we shall therefore call doctrinal belief. If it were possible to apply any test of experience, I should be ready to stake the whole of my earthly goods on my belief that at least one of the planets which we see is inhabited. Hence I say that it is not only an opinion, but a strong belief, on the truth of which I should risk even many advantages of life, that there are inhabitants in other worlds.

  Now we must admit that the doctrine of the existence of God belongs to doctrinal belief. For although, with reference to my theoretical knowledge of the world, I can produce nothing which would make this thought a necessary supposition as a condition of my being able to explain the phenomena of the world, but on the contrary am bound to use my reason as if everything were mere nature, nevertheless, the unity of design is so important a condition of the application of reason to nature that I cannot ignore it, especially as experience supplies so many examples of it. Of that unity of design, however, I know no other condition, which would make it a guidance in my study of nature, but the supposition that a supreme intelligence has ordered all things according to the wisest ends. As a condition, therefore, of, it may be, a contingent, but not unimportant end, namely, in order to have a guidance in the investigation of nature, it is necessary to admit a wise author of the world. The result of my experiment confirms the usefulness of this supposition so many times, while nothing decisive can be adduced against it, that I am really saying far too little, if I call my acceptation of it a mere opinion, and it may be said, even with regard to these theoretical matters, that I firmly believe in God. Still, if we use our words strictly, this belief must always be called doctrinal, and not practical, such as the theology of nature (physical theology) must always and necessarily produce. In the same wisdom, and in the prominent endowments of human nature, combined with the inadequate shortness of life, another sufficient ground may be found for the doctrinal belief in the future life of the human soul.

  The expression of belief is in such cases an expression of modesty from the objective point of view, and yet, at the same time, a firm confidence from a subjective. If even I were to call this purely theoretical acceptance an hypothesis only, which I am entitled to assume, I should profess to be in possession of a more complete concept of the nature of a cause of the world, and of another world, than I really can produce. If I accept anything, even as an hypothesis only, I must know it at least so much according to its properties, that I need not imagine its concepts, but its existence only. But the word belief refers only to the guidance which an idea gives me, and to its subjective influence on the conduct of my reason, which makes me hold it fast, though I may not be able to give an account of it from a speculative point of view.

  Purely doctrinal belief, however, has always a somewhat unstable character. Speculative difficulties often make us lose hold of it, though in the end we always return to it.

  It is quite different with moral belief. For here action is absolutely necessary, that is, I must obey the moral law on all points. The end is here firmly established, and, according to all we know, one only condition is possible under which that end could agree with all other ends, and thus acquire practical validity, namely, the existence of a God and of a future world. I also know it for certain that no one is cognisant of other conditions which could lead to the same unity of ends under the moral law. As, then, the moral precept is at the same time my maxim, reason commanding that it should be so, I shall inevitably believe in the existence of God, and in a future life, and I feel certain that nothing can shake this belief, because all my moral principles would be overthrown at the same time, and I cannot surrender them without becoming hateful in my own eyes.

  We see, therefore, that, even after the failure of all the ambitious schemes of reason to pass beyond the limits of all experience, enough remains to make us satisfied for practical purposes. No one, no doubt, will be able to boast again that he knows that there is a God and a future life. For a man who knows that, is the very man whom I have been so long in search of. As all knowledge, if it refers to an object of pure reason, can be communicated, I might hope that, through his teaching, my own knowledge would be increased in the most wonderful way. No, that conviction is not a logical, but a moral certainty; and, as it rests on subjective grounds (of the moral sentiment), I must not even say that it is morally certain that there is a God, etc., but that I am morally certain, etc. What I really mean is, that the belief in a God and in another world is so interwoven with my moral sentiment, that as there is little danger of my losing the latter, there is quite as little fear lest I should ever be deprived of the former.

  The only point that may rouse misgivings is that this rational belief is based on the supposition of moral sentiments. If we surrender this, and take a man who is entirely indifferent with regard to moral laws, the question proposed by reason becomes merely a problem for speculation, and may in that case be still supported with strong grounds from analogy, but not such to which the most obstinate scepticism has to submit.2

  No man, however, is with regard to these questions free from all interest. For although in the absence of good sentiments he may be rid of all moral interest, enough remains even thus to make him fear the existence of God and a future life. For nothing is required for this but his inability to plead certainty with regard to the nonexistence of such a being and of a future life. As this would have to be proved by mere reason, and therefore apodictically, he would have to establish the impossibility of both, which I feel certain no rational being would venture to do. This would be a negative belief which, though it could not produce morality and good sentiments, would still produce something analogous, namely, a check on the outbreak of evil.

  But, it will be said, is this really all that pure reason can achieve in opening prospects beyond the limits of experience? Nothing more than two articles of faith? Surely even the ordinary understanding could have achieved as much without taking counsel of philosophers!

  I shall not here dwell on the benefits which, by the laborious efforts of its criticism, philosophy has conferred on human reason, granting even that in the end they should turn out to be merely negative. On this point something will have to be said in the next section. But I ask, do you really require that knowledge, which concerns all men, should go beyond the common understanding, and should be revealed to you by philosophers only? The very thing which you find fault with, is the best confirmation of the correctness of our previous assertions, since it reveals to us what we could not have grasped before, namely, that in matters which concern all men without distinction, nature cannot be accused of any partial distribution of her gifts; and that with regard to the essential interests of human nature, the highest philosophy can achieve no more than that guidance which nature has vouchsafed even to the meanest understanding.

  1 All practical concepts relate to objects of pleasure or displeasure, that is, of joy or pain, and, therefore, at least indirectly, to objects of our feelings. But, as feeling is not a faculty of representing things, but lies outside the whole field of our powers of cognition, the
elements of our judgments, so far as they relate to pleasure or pain, that is, the elements of practical judgments, do not belong to transcendental philosophy, which is concerned exclusively with pure cognitions a priori.

  2 The interest which the human mind takes in morality (an interest which, as I believe, is necessary to every rational being) is natural, though it is not undivided, and always practically preponderant. If you strengthen and increase that interest, you will find reason very docile, and even more enlightened, so as to be able to join the speculative with the practical interests. If you do not take care that you first make men at least moderately good, you will never make them honest believers.

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  Method of Transcendentalism

  Chapter III

  The Architectonic of Pure Reason

  By architectonic I understand the art of constructing systems. As systematical unity is that which raises common knowledge to the dignity of a science, that is, changes a mere aggregate of knowledge into a system, it is easy to see that architectonic is the doctrine of what is really scientific in our knowledge, and forms therefore a necessary part of the doctrine of method.