Critique of Pure Reason

by Immanuel Kant

  If, then, it may not be too difficult to leave a bequest to posterity, in the shape of a systematical metaphysic, carried out according to the critique of pure reason, such a bequest is not to be considered therefore as of little value, whether we regard the improvement which reason receives through the secure method of a science, in place of its groundless groping and uncritical vagaries, or whether we look to the better employment of the time of our enquiring youth, who, if brought up in the ordinary dogmatism, are early encouraged to indulge in easy speculations on things of which they know nothing, and of which they, as little as anybody else, will ever understand anything; neglecting the acquirement of sound knowledge, while bent on the discovery of new metaphysical thoughts and opinions. The greatest benefit however will be, that such a work will enable us to put an end for ever to all objections to morality and religion, according to the Socratic method, namely, by the clearest proof of the ignorance of our opponents. Some kind of metaphysic has always existed, and will always exist, and with it a dialectic of pure reason, as being natural to it. It is therefore the first and most important task of philosophy to deprive metaphysic, once for all, of its pernicious influence, by closing up the sources of its errors.

  In spite of these important changes in the whole field of science; and of the losses which speculative reason must suffer in its fancied possessions, all general human interests, and all the advantages which the world hitherto derived from the teachings of pure reason, remain just the same as before. The loss, if any, affects only the monopoly of the schools, and by no means the interests of humanity. I appeal to the staunchest dogmatist, whether the proof of the continued existence of our soul after death, derived from the simplicity of the substance, or that of the freedom of the will, as opposed to the general mechanism of nature, derived from the subtle, but inefficient, distinction between subjective and objective practical necessity, or that of the existence of God, derived from the concept of an Ens realissimum (the contingency of the changeable, and the necessity of a prime mover), have ever, after they had been started by the schools, penetrated the public mind, or exercised the slightest influence on its convictions? If this has not been, and in fact could not be so, on account of the unfitness of the ordinary understanding for such subtle speculations; and if, on the contrary, with regard to the first point, the hope of a future life has chiefly rested on that peculiar character of human nature, never to be satisfied by what is merely temporal (and insufficient, therefore, for the character of its whole destination); if with regard to the second, the clear consciousness of freedom was produced only by the clear exhibition of duties in opposition to all the claims of sensuous desires; and if, lastly, with regard to the third, the belief in a great and wise Author of the world has been supported entirely by the wonderful beauty, order, and providence, everywhere displayed in nature, then this possession remains not only undisturbed, but acquires even greater authority, because the schools have now been taught, not to claim for themselves any higher or fuller insight on a point which concerns general human interests, than what is equally within the reach of the great mass of men, and to confine themselves to the elaboration of these universally comprehensible, and, for moral purposes, quite sufficient proofs. The change therefore affects the arrogant pretensions of the schools only, which would fain be considered as the only judges and depositaries of such truth (as they are, no doubt, with regard to many other subjects), allowing to the public its use only, and trying to keep the key to themselves, quod mecum nescit, solus vult scire videri. At the same time full satisfaction is given to the more moderate claims of speculative philosophers. They still remain the exclusive depositors of a science which benefits the masses without their knowing it, namely, the critique of reason. That critique can never become popular, nor does it need to be so, because, if on the one side the public has no understanding for the fine-drawn arguments in support of useful truths, it is not troubled on the other by the equally subtle objections. It is different with the schools which, in the same way as every man who has once risen to the height of speculation, must know both the pro's and the con's and are bound, by means of a careful investigation of the rights of speculative reason, to prevent, once for all, the scandal which, sooner or later, is sure to be caused even to the masses, by the quarrels in which metaphysicians (and as such, theologians also) become involved, if ignorant of our critique, and by which their doctrine becomes in the end entirely perverted. Thus, and thus alone, can the very root be cut off of materialism, fatalism, atheism, free-thinking, unbelief, fanaticism, and superstition, which may become universally injurious, and finally of idealism and scepticism also, which are dangerous rather to the schools, and can scarcely ever penetrate into the public. If governments think proper ever to interfere with the affairs of the learned, it would be far more consistent with their wise regard for science as well as for society, to favour the freedom of such a criticism by which alone the labours of reason can be established on a firm footing, than to support the ridiculous despotism of the schools, which raise a loud clamour of public danger, whenever the cobwebs are swept away of which the public has never taken the slightest notice, and the loss of which it can therefore never perceive.

  Our critique is not opposed to the dogmatical procedure of reason, as a science of pure knowledge (for this must always be dogmatical, that is, derive its proof from sure principles a priori), but to dogmatism only, that is, to the presumption that it is possible to make any progress with pure (philosophical) knowledge, consisting of concepts, and guided by principles, such as reason has long been in the habit of employing, without first enquiring in what way, and by what right, it has come possessed of them. Dogmatism is therefore the dogmatical procedure of pure reason, without a previous criticism of its own powers; and our opposition to this is not intended to defend either that loquacious shallowness which arrogates to itself the good name of popularity, much less that scepticism which makes short work with the whole of metaphysic. On the contrary, our critique is meant to form a necessary preparation in support of a thoroughly scientific system of metaphysic, which must necessarily be carried out dogmatically and strictly systematically, so as to satisfy all the demands, not so much of the public at large, as of the schools, this being an indispensable condition, as it has undertaken to carry out its work entirely a priori, and thus to the complete satisfaction of speculative reason. In the execution of this plan, as traced out by the critique, that is, in a future system of metaphysic, we shall have to follow in the strict method of the celebrated Wolf, the greatest of all dogmatic philosophers, who first showed (and by his example called forth, in Germany, that spirit of thoroughness, which is not yet extinct) how the secure method of a science could be attained only by a legitimate establishment of principles, a clear definition of concepts, an attempt at strictness of proof, and an avoidance of all bold combinations in concluding. He was therefore most eminently qualified to raise metaphysics to the dignity of a science, if it had only occurred to him, by criticism of the organum, namely, of pure reason itself, first to prepare his field,—an omission to be ascribed, not so much to himself as to the dogmatical spirit of his age, and with regard to which the philosophers of his own, as well as of all previous times, have no right to reproach each other. Those who reject, at the same time, the method of Wolf, and the procedure of the critique of pure reason, can have no other aim but to shake off the fetters of science altogether, and thus to change work into play, conviction into opinion, and philosophy into philodoxy.

  With regard to this second edition, I have tried, as was but fair, to do all I could in order to remove, as far as possible, the difficulties and obscurities which, not perhaps without my fault, have misled even acute thinkers in judging of my book. In the propositions themselves, and their proofs, likewise in the form and completeness of the whole plan, I have found nothing to alter, which is due partly to the long-continued examination to which I had subjected them, before submitting them to the public, and partly to th
e nature of the subject itself. For pure speculative reason is so constituted that it forms a true organism, in which everything is organic, the whole being there for the sake of every part, and every part for the sake of the whole, so that the smallest imperfection, whether a fault or a deficiency, must inevitably betray itself in use. I venture to hope that this system will maintain itself unchanged for the future also. It is not self-conceit which justifies me in this confidence, but the experimental evidence produced by the identity of the result, whether we proceed progressively from the smallest elements to the whole of pure reason, or retrogressively from the whole (for this also is given by the practical objects of reason) to every single part; the fact being, that an attempt at altering even the smallest item produces at once contradictions, not only in the system, but in human reason in general. With regard to the style, however, much remains to be done; and for that purpose, I have endeavoured to introduce several improvements into this second edition, which are intended to remove, first, misapprehensions in the Æsthetic, especially with regard to the concept of time: secondly, obscurities in the deduction of the concepts of the understanding: thirdly, a supposed want of sufficient evidence, in proving the propositions of the pure understanding: fourthly, the false interpretation put on the paralogisms with which we charged rational psychology. To this point (only to the end of the first chapter of transcendental Dialectic) do the changes of style and representation7 extend, and no further. Time was too short for doing more, nor did I, with regard to the rest, meet with any misapprehensions on the part of competent and impartial judges. These, even though I must not name them with that praise which is due to them, will easily perceive in the proper place, that I have paid careful attention to their remarks.

  These improvements, however, entail a small loss to the reader. It was inevitable, without making the book too voluminous, to leave out or abridge several passages which, though not essential to the completeness of the whole, may yet, as useful for other purposes, be missed by some readers. Thus only could I gain room for my new and more intelligible representation of the subject which, though it changes absolutely nothing with regard to propositions, and even to proofs, yet deviates so considerably from the former, in the method of the treatment here and there, that mere additions and interpolations would not have been sufficient. This small loss, which every reader may easily supply by reference to the first edition, will I hope be more than compensated for by the greater clearness of the present.

  I have observed with pleasure and thankfulness in various publications (containing either reviews or separate essays) that the spirit of thoroughness is not yet dead in Germany, but has only been silenced for a short time by the clamour of a fashionable and pretentious licence of thought, and that the difficulties which beset the thorny path of my critique, which is to lead to a truly scientific and, as such, permanent, and therefore most necessary, science of pure reason, have not discouraged bold and clear heads from mastering my book. To these excellent men, who so happily blend thorough knowledge with a talent for lucid exposition (to which I can lay no claim), I leave the task of bringing my, in that respect far from perfect, work to greater perfection. There is no danger of its being refuted, though there is of its being misunderstood. For my own part, I cannot henceforth enter on controversies, though I shall carefully attend to all hints, whether from friends or opponents, in order to utilise them in a future elaboration of the whole system, according to the plan traced out in this propaedeutic. As during these labours I have advanced pretty far in years (this very month, into my sixty-fourth year), I must be careful in spending my time, if I am to carry out my plan, of furnishing a metaphysic of nature, and a metaphysic of morals, in confirmation of the truth of my critique both of speculative and of practical reason, and must leave the elucidation of such obscurities as could at first be hardly avoided in such a work, and likewise the defence of the whole, to those excellent men who have made it their own. At single points every philosophical treatise may be pricked (for it cannot be armed at all points, like a mathematical one), while yet the organic structure of the system, considered as a whole, has not therefore to apprehend the slightest danger. Few only have that pliability of intellect to take in the whole of a system, if it is new; still fewer have an inclination for it, because they dislike every innovation. If we take single passages out of their connection, and contrast them with each other, it is easy to pick out apparent contradictions, particularly in a work written with all the freedom of a running speech. In the eyes of those who rely on the judgment of others, such contradictions may throw an unfavourable light on any work; but they are easily removed, if we ourselves have once grasped the idea of the whole. And, if a theory possesses stability in itself, then this action and reaction of praise and blame, which at first seemed so dangerous, serve only in time to rub off its superficial inequalities: nay, secure to it, in a short time, the requisite elegance also, if only men of insight, impartiality, and true popularity will devote themselves to its study.

  Königsberg, April, 1787.

  Supplement III

  Table of Contents

  of the Second Edition (1787), with the paging of that edition

  Introduction

  I. Of the difference between pure and empirical knowledge

  II. We are in possession of certain cognitions a priori, and even the ordinary understanding is never without them

  III. Philosophy requires a science, to determine the possibility, the principles, and the extent of all cognitions a priori

  IV. Of the difference between analytical and synthetical judgments

  V. In all theoretical sciences of reason synthetical judgments a priori are contained as principles

  VI. The general problem of pure reason

  VII. Idea and division of an independent science under the name of Critique of Pure Reason

  I. Elements of Transcendentalism

  First Part. Transcendental Æsthetic

  Introduction. § 1

  First Section. Of Space. § 2, 3

  Second Section. Of Time. § 4-7

  General Observations on transcendental Æsthetic. § 8

  Conclusion of transcendental Æsthetic

  Second Part. Transcendental Logic

  Introduction. The idea of a transcendental Logic

  I. Of Logic in general

  II. Of transcendental Logic

  III. Of the division of general Logic into analytical and dialectical

  IV. Of the division of transcendental Logic into transcendental Analytic and Dialectic

  First Division. Transcendental Analytic

  First Book. Analytic of concepts

  First Chapter. Method of discovering all pure concepts of the understanding

  First Section. Of the logical use of the understanding in general

  Second Section. Of the logical function of the understanding in judgments. § 9

  Third Section. Of the pure concepts of the understanding, or of the Categories. § 10-12

  Second Chapter. Of the deduction of the pure concepts of the understanding

  First Section. Of the principles of a transcendental deduction in general. § 13

  Transition to a transcendental deduction of the Categories. § 14

  Second Section. Transcendental deduction of the pure concepts of the understanding. § 15-27

  Second Book. Analytic of principles (transcendental doctrine of the faculty of judgment)

  Introduction. Of the transcendental faculty of judgment in general

  First Chapter. Of the schematism of the pure concepts of the understanding

  Second Chapter. System of all principles of the pure understanding

  First Section. Of the highest principle of all analytical judgments

  Second Section. Of the highest principle of all synthetical judgments

  Third Section. Systematical representation of all synthetical principles of the pure understanding

  1. Axioms of intuition

  2. A
nticipations of perception

  3. Analogies of experience

  First Analogy. Principle of the permanence of substance

  Second Analogy. Principle of the succession of time, according to the law of causality

  Third Analogy. Principle of coexistence, according to the law of reciprocity

  4. Postulates of empirical thought in general

  General note on the system of the principles

  Third Chapter. On the ground of distinction of all subjects into phenomena and noumena

  Appendix. On the amphiboly of reflective concepts owing to the confusion of the empirical with the transcendental use of the understanding

  Second Division. Transcendental Dialectic

  Introduction

  I. Of transcendental illusion

  II. Of pure reason as the seat of transcendental illusion

  A. Of reason in general

  B. Of the logical use of reason

  C. Of the pure use of reason

  First Book. Of the concepts of pure reason

  First Section. Of ideas in general

  Second Section. Of transcendental ideas

  Third Section. System of transcendental ideas