II.1. The Discipline of Pure Reason in respect of its Polemical Employment

Reason must in all its undertakings subject itself to criticism; should it limit freedom of criticism by any prohibitions, it must harm itself, drawing upon itself a damaging suspicion. Nothing is so important through its usefulness, nothing so sacred, that it may be exempted from this searching examination, which knows no respect for persons. Reason depends on this freedom for its very existence. For reason has no dictatorial authority; its verdict is always simply the agreement of free citizens, of whom each one must be permitted to express, without let or hindrance, his objections or even his veto.

But while reason can never refuse to submit to criticism, it does not always have cause to fear it. In its dogmatic (non-mathematical) employment it is not, indeed, so thoroughly conscious of such exact observation of its own supreme laws, as not to feel constrained to present itself with diffidence, nay, with entire renunciation of all assumed dogmatic authority, to the critical scrutiny of a higher judicial reason.

The situation is, however, quite otherwise, when reason has to deal not with the verdict of a judge, but with the claims of a fellow-citizen, and against these has only to act in self-defence. For since these are intended to be just as dogmatic in denial as its own are in affirmation, it is able to justify itself κατ’ ἄνθρωπον, in a manner which ensures it against all interference, and provides it with a title to secure possession that need fear no outside claims, although κατ’ ἀλήθειαν the title cannot itself be conclusively proved.

By the polemical employment of pure reason I mean the defence of its propositions as against the dogmatic counter-propositions through which they are denied. Here the contention is not that its own assertions may not, perhaps, be false, but only that no one can assert the opposite with apodeictic certainty, or even, indeed, with a greater degree of likelihood. We do not here hold our possessions upon sufferance; for although our title to them may not be satisfactory, it is yet quite certain that no one can ever be in a position to prove the illegality of the title.

It is grievous, indeed, and disheartening, that there should be any such thing as an antithetic of pure reason, and that reason, which is the highest tribunal for all conflicts, should thus be at variance with itself. We had to deal, in a previous chapter, with such an antithetic; but it turned out to be only an apparent conflict, resting upon a misunderstanding. In accordance with the common prejudice, it took appearances as being things in themselves, and then required an absolute completeness of their synthesis in the one mode or in the other (this being equally impossible in either way)—a demand which is not at all permissible in respect of appearances. There was, therefore, no real self-contradiction of reason in the propounding of the two propositions, that the series of appearances given in themselves has an absolutely first beginning, and that this series is absolutely and in itself without any beginning. For the two propositions are quite consistent with each other, inasmuch as appearances, in respect of their existence (as appearances), are in themselves nothing at all, that is, [so regarded] are something self-contradictory; for the assumption [that they do thus exist in themselves] must naturally lead to self-contradictory inferences.

But there are other cases in which we cannot allege any such misunderstanding, and in which we cannot, therefore, dispose of the conflict of reason in the above manner—when, for instance, it is asserted, on the one hand, theistically, that there is a supreme being, and on the other hand, atheistically, that there is no supreme being; or as in psychology, that everything which thinks is endowed with absolute and abiding unity and is therefore distinct from all transitory material unity, and, in opposition thereto, that the soul is not immaterial unity and cannot be exempt from transitoriness. For since in these cases the understanding has to deal only with things in themselves and not with appearances, the object of such questions is free from any foreign element that is in contradiction with its nature. There would indeed be a real conflict, if pure reason had anything to say on the negative side which amounted to a positive ground for its negative contentions. For so far as concerns criticism of the grounds of proof offered by those who make dogmatic affirmations, the criticism can be freely admitted, without our having on that account to give up these affirmations, which have at least the interest of reason in their favour—an interest to which the opposite party cannot appeal.

I do not at all share the opinion which certain excellent and thoughtful men (such as Sulzer), in face of the weakness of the arguments hitherto employed, have so often been led to express, that we may hope sometime to discover conclusive demonstrations of the two cardinal propositions of our reason—that there is a God, and that there is a future life. On the contrary, I am certain that this will never happen. For whence will reason obtain ground for such synthetic assertions, which do not relate to objects of experience and their inner possibility. But it is also apodeictically certain that there will never be anyone who will be able to assert the opposite with the least show [of proof], much less, dogmatically. For since he could prove this only through pure reason, he must undertake to prove that a supreme being, and the thinking subject in us [viewed] as pure intelligence, are impossible. But whence will he obtain the modes of knowledge which could justify him in thus judging synthetically in regard to things that lie beyond all possible experience. We may therefore be so completely assured that no one will ever prove the opposite, that there is no need for us to concern ourselves with formal arguments. We are always in a position to accept these propositions—propositions which are so very closely bound up with the speculative interest of our reason in its empirical employment, and which, moreover, are the sole means of reconciling the speculative with the practical interest. As against our opponent, who must not be considered here as a critic only, we are equipped with our non liquet, which cannot fail to disconcert him. At the same time we do not mind his turning this argument upon ourselves, since we always have in reserve the subjective maxim of reason, which is necessarily lacking to our opponent, and under its protection can look upon all his vain attacks with a tranquil indifference.

There is thus no real antithetic of pure reason. For the arena for such an antithetic would have to be located in the domain of pure theology and psychology; and in that domain no combatant can be adequately equipped, or have weapons that we need fear. Ridicule and boasting form his whole armoury, and these can be laughed at, as mere child’s play. This is a comforting consideration, and affords reason fresh courage; for upon what could it rely, if, while it alone is called upon to remove all errors, it should yet be at variance with itself, and without hope of peace and quiet possession.

Everything which nature has itself instituted is good for some purpose. Even poisons have their use. They serve to counteract other poisons generated in our bodily humours, and must have a place in every complete pharmacopoeia. The objections against the persuasions and complacency of our purely speculative reason arise from the very nature of reason itself, and must therefore have their own good use and purpose, which ought not to be disdained. Why has Providence placed many things which are closely bound up with our highest interests so far beyond our reach that we are only permitted to apprehend them in a manner lacking in clearness and subject to doubt—in such fashion that our enquiring gaze is more excited than satisfied? We may, indeed, be in doubt whether it serves any useful purpose, and whether it is not perhaps even harmful, to venture upon bold utterances in regard to such uncertain matters. But there can be no manner of doubt that it is always best to grant reason complete liberty, both of enquiry and of criticism, so that it may not be hindered in attending to its own proper interests. These interests are no less furthered by the limitation than by the extension of its speculations, and will always suffer when outside influences intervene to divert it from its proper path, and to constrain it by what is irrelevant to its own proper ends.

Allow, therefore, your opponent to speak in the name of reason, and combat him only with weapons of reason. For the rest, have no anxiety as to the outcome in its bearing upon our practical interests, since in a merely speculative dispute they are never in any way affected. The conflict serves only to disclose a certain antinomy of reason which, inasmuch as it is due to the very nature of reason, must receive a hearing and be scrutinised. Reason is benefited by the consideration of its object from both sides, and its judgment is corrected in being thus limited. What is here in dispute is not the practical interests of reason but the mode of their presentation. For although we have to surrender the language of knowledge, we still have sufficient ground to employ, in the presence of the most exacting reason, the quite legitimate language of a firm faith.

If we should ask the dispassionate David Hume, [by temperament] so peculiarly fitted for balanced judgment, what led him to undermine, through far-fetched subtleties so elaborately thought out, the conviction which is so comforting and beneficial for mankind, that their reason has sufficient insight for the assertion and for the determinate conception of a supreme being, he would answer: ‘Solely in order to advance reason in its self-knowledge, and because of a certain indignation at the violence that is done to reason by those who, while boasting of its powers, yet hinder it from candid admission of the weaknesses which have become obvious to it through its own self-examination’. If, on the other hand, we should ask Priestley, who was wholly devoted to the empirical employment of reason and out of sympathy with all transcendent speculation, what motives had induced him—himself a pious and zealous teacher of religion—to pull down two such pillars of all religion as the freedom and immortality of the soul (the hope of a future life is for him only the expectation of the miracle of resurrection), he would not be able to give any other answer than that he was concerned for the interest of reason, which must suffer when we seek to exempt certain objects from the laws of material nature, the only laws which we can know and determine with exactitude. It would be unjust to decry the latter (who knew how to combine his paradoxical teaching with the interests of religion), and so to give pain to a well-intentioned man, simply because he is unable to find his bearings, having strayed outside the field of natural science. And the same favour must be accorded to the no less well disposed and in his moral character quite blameless Hume, when he insists upon the relevance, in this field, of his subtly thought-out speculations. For, as he rightly held, their object lies entirely outside the limits of natural science, in the domain of pure ideas.

What, then, is to be done, especially in view of the danger which would thus seem to threaten the best interests of mankind? Nothing is more natural, nothing is more reasonable, than the decision which we are hereby called upon to make. Leave such thinkers free to take their own line. If they exhibit talent, if they initiate new and profound enquiries, in a word, if they show reason, reason always stands to gain. If we resort to other means than those of untrammelled reason, if we raise the cry of high treason, and act as if we were summoning the vulgar to extinguish a conflagration—the vulgar who have no understanding of such subtle enquiries—we make ourselves ridiculous. For the question at issue is not as to what, in these enquiries, is beneficial or detrimental to the best interests of mankind, but only how far reason can advance by means of speculation that abstracts from all interests, and whether such speculation can count for anything, or must not rather be given up in exchange for the practical. Instead, therefore, of rushing into the fight, sword in hand, we should rather play the part of the peaceable onlooker, from the safe seat of the critic. The struggle is indeed toilsome to the combatants, but for us can be entertaining; and its outcome—certain to be quite bloodless—must be of advantage as contributing to our theoretical insight. For it is indeed absurd to look to reason for enlightenment, and yet to prescribe beforehand which side she must necessarily favour. Besides, reason is already of itself so confined and held within limits by reason, that we have no need to call out the guard, with a view to bringing the civil power to bear upon that party whose alarming superiority may seem to us to be dangerous. In this dialectic no victory is gained that need give us cause for anxiety.

Reason does indeed stand in sore need of such dialectical debate; and it is greatly to be wished that the debate had been instituted sooner and with unqualified public approval. For in that case criticism would sooner have reached a ripe maturity, and all these disputes would of necessity at once have come to an end, the opposing parties having learned to recognise the illusions and prejudices which have set them at variance.

There is in human nature a certain disingenuousness, which, like everything that comes from nature, must finally contribute to good ends, namely, a disposition to conceal our real sentiments, and to make show of certain assumed sentiments which are regarded as good and creditable. This tendency to conceal ourselves and to assume the appearance of what contributes to our advantage, has, undoubtedly, not only civilised us, but gradually, in a certain measure, moralised us. For so long as we were not in a position to see through the outward show of respectability, honesty, and modesty, we found in the seemingly genuine examples of goodness with which we were surrounded a school for self-improvement. But this disposition to represent ourselves as better than we are, and to give expression to sentiments which we do not share, serves as a merely provisional arrangement, to lead us from the state of savage rudeness, and to allow of our assuming at least the outward bearing of what we know to be good. But later, when true principles have been developed, and have become part of our way of thought, this duplicity must be more and more earnestly combated; otherwise it corrupts the heart, and checks the growth of good sentiments with the rank weeds of fair appearances.

I am sorry to observe the same disingenuousness, misrepresentation, and hypocrisy even in the utterances of speculative thought, where there are far fewer hindrances to our making, as is fitting, frank and unreserved admission of our thoughts, and no advantage whatsoever in acting otherwise. For what can be more prejudicial to the interests of knowledge than to communicate even our very thoughts in a falsified form, to conceal doubts which we feel in regard to our own assertions, or to give an appearance of conclusiveness to grounds of proofs which we ourselves recognise to be insufficient. So long as mere personal vanity is what breeds these secret devices—and this is generally the case with those speculative judgments which concern no special interest and do not easily allow of apodeictic certainty—it is counteracted, in the process of enlisting general acceptance, by the vanity of others; and thus in the end the result is the same as would have been obtained, though much sooner, by entirely sincere and honest procedure. When the common people are of opinion that those who indulge in subtle questionings aim at nothing less than to shake the very foundations of public welfare, it may, indeed, seem not only prudent but permissible, and indeed even commendable, to further the good cause through sophistical arguments rather than allow its supposed antagonists the advantage of having made us lower our tone to that of a merely practical conviction, and of having compelled us to admit our lack of speculative and apodeictic certainty. I cannot, however, but think that nothing is so entirely incompatible with the purpose of maintaining a good cause as deceit, hypocrisy, and fraud. Surely the least that can be demanded is that in a matter of pure speculation, when weighing the considerations cited by reason, we should proceed in an entirely sincere manner. If we could confidently count even upon this little, the conflict of speculative reason regarding the important questions of God, the immortality of the soul, and freedom, would long ago have been decided, or would very soon be brought to a conclusion. Thus it often happens that purity of purpose is in inverse ratio to the goodness of the cause, and that candour and honesty are perhaps more likely to be found among its assailants than among its defenders.

I shall therefore assume that I have readers who do not wish to see a righteous cause defended in an unrighteous manner; and that they will consequently take it as agreed, that, according to our principles of criticism, and having regard not to what commonly happens, but to what ought to happen, there can, properly speaking, be no polemic of pure reason. For how can two persons carry on a dispute about a thing the reality of which neither of them can present in actual or even in possible experience—a dispute in which they brood over the mere idea of the thing, in order to extract from it something more than the idea, namely, the reality of the object itself? What means have they of ending the dispute, since neither of them can make his thesis genuinely comprehensible and certain, but only attack and refute that of his opponent? For this is the fate of all assertions of pure reason: that since they transcend the conditions of all possible experience, outside which the authentication of truth is in no wise possible, while at the same time they have to make use of the laws of the understanding—laws which are adapted only for empirical employment, but without which no step can be taken in synthetic thought—neither side can avoid exposing its weakness, and each can therefore take advantage of the weakness of the other.

The critique of pure reason can be regarded as the true tribunal for all disputes of pure reason; for it is not involved in these disputes—disputes which are immediately concerned with objects—but is directed to the determining and estimating of the rights of reason in general, in accordance with the principles of their first institution.

In the absence of this critique reason is, as it were, in the state of nature, and can establish and secure its assertions and claims only through war. The critique, on the other hand, arriving at all its decisions in the light of fundamental principles of its own institution, the authority of which no one can question, secures to us the peace of a legal order, in which our disputes have to be conducted solely by the recognised methods of legal action. In the former state, the disputes are ended by a victory to which both sides lay claim, and which is generally followed by a merely temporary armistice, arranged by some mediating authority; in the latter, by a judicial sentence which, as it strikes at the very root of the conflicts, effectively secures an eternal peace. The endless disputes of a merely dogmatic reason thus finally constrain us to seek relief in some critique of reason itself, and in a legislation based upon such criticism. As Hobbes maintains, the state of nature is a state of injustice and violence, and we have no option save to abandon it and submit ourselves to the constraint of law, which limits our freedom solely in order that it may be consistent with the freedom of others and with the common good of all.

This freedom will carry with it the right to submit openly for discussion the thoughts and doubts with which we find ourselves unable to deal, and to do so without being decried as troublesome and dangerous citizens. This is one of the original rights of human reason, which recognises no other judge than that universal human reason in which everyone has his say. And since all improvement of which our state is capable must be obtained from this source, such a right is sacred and must not be curtailed. Indeed we are very ill-advised in decrying as dangerous any bold assertions against, or audacious attacks upon, the view which already has on its side the approval of the largest and best portion of the community; in so doing we are ascribing to them an importance which they are not entitled to claim. Whenever I hear that a writer of real ability has demonstrated away the freedom of the human will, the hope of a future life, and the existence of God, I am eager to read the book, for I expect him by his talents to increase my insight into these matters. Already, before having opened it, I am perfectly certain that he has not justified any one of his specific claims; not because I believe that I am in possession of conclusive proofs of these important propositions, but because the transcendental critique, which has disclosed to me all the resources of our pure reason, has completely convinced me that, as reason is incompetent to arrive at affirmative assertions in this field, it is equally unable, indeed even less able, to establish any negative conclusion in regard to these questions. For from what source will the freethinker derive his professed knowledge that there is, for example, no supreme being? This proposition is outside the field of possible experience, and therefore beyond the limits of all human insight. The reply of the dogmatic defender of the good cause I should not read at all. I know beforehand that he will attack the sophistical arguments of his opponent simply in order to gain acceptance for his own; and I also know that a quite familiar line of false argument does not yield so much material for new observations as one that is novel and ingeniously elaborated. The opponent of religion is indeed, in his own way, no less dogmatic, but he affords me a welcome opportunity of applying and, in this or that respect, amending the principles of my Critique, while at the same time I need be in no fear of these principles being in the least degree endangered.

But must not the young, at least, when entrusted to our academical teaching, be warned against such writings, and preserved from a premature knowledge of such dangerous propositions, until their faculty of judgment is mature, or rather until the doctrine which we seek to instil into them has taken such firm root, that they are able effectively to withstand all persuasion to contrary views, from whatever quarter it may come?

If we are to insist on holding to dogmatic procedure in matters of pure reason, and on disposing of our opponents in strictly polemical fashion, that is, by ourselves taking sides in the controversy, and therefore equipping ourselves with proofs in support of the opposite assertions, certainly this procedure would for the time being be the most expedient; but in the long run nothing would be more foolish and ineffective than to keep youthful reason thus for a period under tutelage. This will indeed guard the young temporarily against perversion. But when, later, either curiosity or the fashion of the age brings such writings under their notice, will their youthful conviction then stand the test? Whoever, in withstanding the attacks of his opponent, has at his disposal only dogmatic weapons, and is unable to develop the dialectic which lies concealed in his own breast no less than in that of his antagonist, [is in a dangerous position]. He sees sophistical arguments, which have the attraction of novelty, set in opposition to sophistical arguments which no longer have that attraction, but, on the contrary, tend to arouse the suspicion that advantage has been taken of his youthful credulity. And accordingly he comes to believe that there can be no better way of showing that he has outgrown childish discipline than by casting aside these well-meant warnings; and accustomed as he is to dogmatism, he drinks deep draughts of the poison, which destroys his principles by a counter-dogmatism.

In academic teaching we ought to pursue the course exactly opposite to that which is here recommended, provided always that the teaching is based on thorough instruction in the criticism of pure reason. For in order to bring the principles of this criticism into operation as soon as possible, and to show their sufficiency even when dialectical illusion is at its height, it is absolutely necessary that the attacks which seem so terrible to the dogmatist should be made to exercise their full force upon the pupil’s reason, which though still weak has been enlightened through criticism, and that the pupil should thus be allowed the opportunity of testing for himself, one by one, by reference to the critical principles, how groundless are the assertions of those who have launched these attacks. As it is by no means difficult for him to resolve these arguments into thin air, he early begins to feel his own capacity to secure himself against such injurious deceptions, which must finally lose for him all their illusory power. Those same blows which destroy the structures of the enemy must indeed be equally destructive to any speculative structure which he may perchance himself wish to erect. This does not, however, in the least disturb him, since he has no need of any such shelter, being still in possession of good expectations in the practical sphere, where he may confidently hope to find firmer ground upon which to erect his own rational and beneficial system.

There is, therefore, properly speaking, no polemic in the field of pure reason. Both parties beat the air, and wrestle with their own shadows, since they go beyond the limits of nature, where there is nothing that they can seize and hold with their dogmatic grasp. Fight as they may, the shadows which they cleave asunder grow together again forthwith, like the heroes in Valhalla, to disport themselves anew in the bloodless contests.

But neither can we admit that there is any sceptical employment of pure reason, such as might be entitled the principle of neutrality in all its disputes. To set reason at variance with itself, to supply it with weapons on both sides, and then to look on, quietly and scoffingly, at the fierce struggle, is not, from the dogmatic point of view, a seemly spectacle, but appears to suggest a mischievous and malevolent disposition. If, however, we consider the invincible obstinacy and the boastfulness of those who argue dogmatically, and who refuse to allow their claims to be moderated by any criticism, there is really no other available course of action than to set against the boasting of the one side the no less justified boasting of the other, in the hope that the resistance thus offered to reason may at least serve to disconcert it, to awaken some doubts as to its pretensions, and to make it willing to give a hearing to criticism. But to allow ourselves simply to acquiesce in these doubts, and thereupon to set out to commend the conviction and admission of our ignorance not merely as a remedy against the complacency of the dogmatists, but likewise as the right method of putting an end to the conflict of reason with itself, is a futile procedure, and can never suffice to overcome the restlessness of reason. At best it is merely a means of awakening it from its sweet dogmatic dreams, and of inducing it to enter upon a more careful examination of its own position. Since, however, the sceptical method of escaping from the troublesome affairs of reason appears to be, as it were, a short cut by which we can arrive at a permanent peace in philosophy, or [if it be not that], is at least the road favoured by those who would feign make show of having a philosophical justification for their contemptuous dislike of all enquiries of this kind, I consider it necessary to exhibit this way of thinking in its true light.

The consciousness of my ignorance (unless at the same time this ignorance is recognised as being necessary), instead of ending my enquiries, ought rather to be itself the reason for entering upon them. All ignorance is either ignorance of things or ignorance of the function and limits of knowledge. If ignorance is only accidental, it must incite me, in the former regard to a dogmatic enquiry concerning things (objects), in the latter regard to a critical enquiry concerning the limits of my possible knowledge. But that my ignorance is absolutely necessary, and that I am therefore absolved from all further enquiry, cannot be established empirically, from observation, but only through an examination, critically conducted, of the primary sources of our knowledge. The determination of the limits of our reason cannot, therefore, be made save on a priori grounds; on the other hand, that limitation of it which consists merely in an indeterminate knowledge of an ignorance never to be completely removed, can be recognised a posteriori by reference to that which, notwithstanding all we know, still remains to be known. The former knowledge of our ignorance, which is possible only through criticism of reason itself, is science; the latter is nothing but perception, and we cannot say inferences from perception may extend. If I represent the earth as it appears to my senses, as a flat surface, with a circular horizon, I cannot know how far it extends. But experience teaches me that wherever I may go, I always see a space around me in which I could proceed further; and thus I know the limits of my actual knowledge of the earth at any given time, but not the limits of all possible geography. But if I have got so far as to know that the earth is a sphere and that its surface is spherical, I am able even from a small part of it, for instance, from the magnitude of a degree, to know determinately, in accordance with principles a priori, the diameter, and through it the total superficial area of the earth; and although I am ignorant of the objects which this surface may contain, I yet have knowledge in respect of its circuit, magnitude, and limits.

The sum of all the possible objects of our knowledge appears to us to be a plane, with an apparent horizon—namely, that which in its sweep comprehends it all, and which has been entitled by us the idea of unconditioned totality. To reach this concept empirically is impossible, and all attempts to determine it a priori in accordance with an assured principle have proved vain. None the less all the questions raised by our pure reason are as to what may be outside the horizon, or, it may be, on its boundary line.

The celebrated David Hume was one of those geographers of human reason who have imagined that they have sufficiently disposed of all such questions by setting them outside the horizon of human reason—a horizon which yet he was not able to determine. Hume dwelt in particular upon the principle of causality, and quite rightly observed that its truth, and even the objective validity of the concept of efficient cause in general, is based on no insight, that is, on no a priori knowledge, and that its authority cannot therefore be ascribed to its necessity, but merely to its general utility in the course of experience, and to a certain subjective necessity which it thereby acquires, and which he entitles custom. From the incapacity of our reason to make use of this principle in any manner that transcends experience, he inferred the nullity of all pretensions of reason to advance beyond the empirical.

A procedure of this kind—subjecting the facts of reason to examination, and if necessary to blame—may be entitled the censorship of reason. This censorship must certainly lead to doubt regarding all transcendent employment of principles. But this is only the second step, and does not by any means complete the work of enquiry. The first step in matters of pure reason, marking its infancy, is dogmatic. The second step is sceptical, and indicates that experience has rendered our judgment wiser and more circumspect. But a third step, such as can be taken only by fully matured judgment, based on assured principles of proved universality, is now necessary, namely, to subject to examination, not the facts of reason, but reason itself, in the whole extent of its powers, and as regards its aptitude for pure a priori modes of knowledge. This is not the censorship but the criticism of reason, whereby not its present bounds but its determinate [and necessary] limits, not its ignorance on this or that point but its ignorance in regard to all possible questions of a certain kind, are demonstrated from principles, and not merely arrived at by way of conjecture. Scepticism is thus a resting-place for human reason, where it can reflect upon its dogmatic wanderings and make survey of the region in which it finds itself, so that for the future it may be able to choose its path with more certainty. But it is no dwelling-place for permanent settlement. Such can be obtained only through perfect certainty in our knowledge, alike of the objects themselves and of the limits within which all our knowledge of objects is enclosed.

Our reason is not like a plane indefinitely far extended, the limits of which we know in a general way only; but must rather be compared to a sphere, the radius of which can be determined from the curvature of the arc of its surface—that is to say, from the nature of synthetic a priori propositions—and whereby we can likewise specify with certainty its volume and its limits. Outside this sphere (the field of experience) there is nothing that can be an object for reason; nay, the very questions in regard to such supposed objects relate only to subjective principles of a complete determination of those relations which can come under the concepts of the understanding and which can be found within the empirical sphere.

We are actually in possession of a priori synthetic modes of knowledge, as is shown by the principles of understanding which anticipate experience. If anyone is quite unable to comprehend the possibility of these principles, he may at first be inclined to doubt whether they actually dwell in us a priori; but he cannot on this account declare that they are beyond the powers of the understanding, and so represent all the steps which reason takes under their guidance as being null and void. All that he can say is that if we could have insight into their origin and authenticity, we should be able to determine the scope and limits of our reason, but that until we can have such insight any assertions as to the limits of reason are made at random. And on this ground a general doubt regarding all dogmatic philosophy, proceeding as such philosophy does without criticism of reason itself, is entirely justified; but we cannot therefore altogether deny to reason the right to take such forward steps, once we have prepared and secured the way for them by a more thorough preparation of the ground. For all the concepts, nay, all the questions, which pure reason presents to us, have their source not in experience, but exclusively in reason itself, and must therefore allow of solution and of being determined in regard to their validity or invalidity. We have no right to ignore these problems, as if their solution really depended on the nature of things, and as if we might therefore, on the plea of our incapacity, decline to occupy ourselves with their further investigation; for since reason is the sole begetter of these ideas, it is under obligation to give an account of their validity or of their illusory, dialectical nature.

All sceptical polemic should properly be directed only against the dogmatist, who, without any misgivings as to his fundamental objective principles, that is, without criticism, proceeds complacently upon his adopted path; it should be designed simply to put him out of countenance and thus to bring him to self-knowledge. In itself, however, this polemic is of no avail whatsoever in enabling us to decide what it is that we can and what it is that we cannot know. All unsuccessful dogmatic attempts of reason are facts, and it is always of advantage to submit them to the censorship of the sceptic. But this can decide nothing regarding those expectations of reason which lead it to hope for better success in its future attempts, and to build claims on this foundation; and consequently no mere censorship can put an end to the dispute regarding the rights of human reason.

Hume is perhaps the most ingenious of all the sceptics, and beyond all question is without rival in respect of the influence which the sceptical procedure can exercise in awakening reason to a thorough self-examination. It will therefore well repay us to make clear to ourselves, so far as may be relevant to our purpose, the course of the reasoning, and the errors, of so acute and estimable a man—a course of reasoning which at the start was certainly on the track of truth.

Hume was perhaps aware, although he never followed the matter out, that in judgments of a certain kind we pass beyond our concept of the object. I have entitled this kind of judgments synthetic. There is no difficulty as to how, by means of experience, I can pass beyond the concept which I previously have. Experience is in itself a synthesis of perceptions, whereby the concept which I have obtained by means of a perception is increased through the addition of other perceptions. But we suppose ourselves to be able to pass a priori beyond our concept, and so to extend our knowledge. This we attempt to do either through the pure understanding, in respect of that which is at least capable of being an object of experience, or through pure reason, in respect of such properties of things, or indeed even of the existence of such things, as can never be met with in experience. Our sceptical philosopher did not distinguish these two kinds of judgments, as he yet ought to have done, but straightway proceeded to treat this self-increment of concepts, and, as we may say, this spontaneous generation on the part of our understanding and of our reason, without impregnation by experience, as being impossible. He therefore regarded all the supposed a priori principles of these faculties as fictitious, and concluded that they are nothing but a custom-bred habit arising from experience and its laws, and are consequently merely empirical, that is, rules that are in themselves contingent, and to which we ascribe a supposititious necessity and universality. In support of his assertion of this startling thesis, he cited the universally recognised principle of the relation between cause and effect. For since no faculty of understanding can carry us from the concept of a thing to the existence of something else that is thereby universally and necessarily given, he believed that he was therefore in a position to conclude that in the absence of experience we have nothing that can increase our concept and justify us in propounding a judgment which thus enlarges itself a priori. That sunlight should melt wax and yet also harden clay, no understanding, he pointed out, can discover from the concepts which we previously possessed of these things, much less infer them according to a law. Only experience is able to teach us such a law. But, as we have discovered in the Transcendental Logic, although we can never pass immediately beyond the content of the concept which is given us, we are nevertheless able, in relation to a third thing, namely, possible experience, to know the law of its connection with other things, and to do so in an a priori manner. If, therefore, wax, which was formerly hard, melts, I can know a priori that something must have preceded, ([that something being] for instance [in this case] the heat of the sun), upon which the melting has followed according to a fixed law, although a priori, independently of experience, I could not determine, in any specific manner, either the cause from the effect, or the effect from the cause. Hume was therefore in error in inferring from the contingency of our determination in accordance with the law the contingency of the law itself. The passing beyond the concept of a thing to possible experience (which takes place a priori and constitutes the objective reality of the concept) he confounded with the synthesis of the objects of actual experience, which is always empirical. He thus confounds a principle of affinity, which has its seat in the understanding and affirms necessary connection, with a rule of association, which exists only in the imitative faculty of imagination, and which can exhibit only contingent, not objective, connections.

The sceptical errors of this otherwise singularly acute thinker arose chiefly from a defect which he shares in common with all dogmatists, namely, that he did not make a systematic review of all the various kinds of a priori synthesis ascribable to the understanding. For he would then have found, to mention only one of many possible examples, that the principle of permanence is a principle of this character, and that, like the principle of causality, it anticipates experience. He would thus have been able to prescribe determinate limits to the activities whereby the understanding and pure reason extend themselves a priori. Instead of so doing, he merely restricts the understanding, without defining its limits, and while creating a general mistrust fails to supply any determinate knowledge of the ignorance which for us is unavoidable. For while subjecting to censorship certain principles of the understanding, he makes no attempt to assess the understanding itself, in respect of all its powers, by the assay-balance of criticism; while rightly denying to the understanding what it cannot really supply, he goes on to deny it all power of extending itself a priori, and this in spite of his never having tested it as a whole. Thus the fate that waits upon all scepticism likewise befalls Hume, namely, that his own sceptical teaching comes to be doubted, as being based only on facts which are contingent, not on principles which can constrain to a necessary renunciation of all right to dogmatic assertions.

Further, he draws no distinction between the well-grounded claims of the understanding and the dialectical pretensions of reason, though it is indeed chiefly against the latter that his attacks are directed. Accordingly that peculiarly characteristic ardour with which reason insists upon giving free rein to itself, has not in the least been disturbed but only temporarily impeded. It does not feel that it has been shut out from the field in which it is wont to disport itself; and so, in spite of its being thwarted in this and that direction, it cannot be made entirely to desist from these ventures. On the contrary, the attacks lead only to counter-preparations, and make us the more obstinate in insisting upon our own views. But a complete review of all the powers of reason—and the conviction thereby obtained of the certainty of its claims to a modest territory, as also of the vanity of higher pretensions—puts an end to the conflict, and induces it to rest satisfied with a limited but undisputed patrimony.

To the uncritical dogmatist, who has not surveyed the sphere of his understanding, and therefore has not determined, in accordance with principles, the limits of his possible knowledge, these sceptical attacks are not only dangerous but even destructive. For he does not know beforehand how far his powers extend, and indeed believes that their limits can be determined by the simple method of trial and failure. In consequence of this, if on being attacked there is a single one of his assertions that he is unable to justify, or which involves illusion for which he also cannot account in terms of any principles, suspicion falls on all his contentions, however plausible they may appear.

The sceptic is thus the taskmaster who constrains the dogmatic reasoner to develop a sound critique of the understanding and reason. When we have advanced thus far, we need fear no further challenge, since we have learned to distinguish our real possessions from that which lies entirely outside them; and as we make no claims in regard to this latter domain, we cannot become involved in any dispute in respect to it. While, therefore, the sceptical procedure cannot of itself yield any satisfying answer to the questions of reason, none the less it prepares the way by arousing reason to circumspection, and by indicating the radical measures which are adequate to secure it in its legitimate possessions.