The Online Library of Liberty

A project of Liberty Fund, Inc.

• Dedication
• Preface 1
• Translator’s Preface
• Translator’s Preface to Second Edition
• Introduction [p. 1]
• I: The Idea of Transcendental Philosophy
• II: Division of Transcendental Philosophy
• I: The Elements of Transcendentalism
• Part I: Transcendental Æsthetic [p. 19]
• Section I: Of Space
• Section II: Of Time
• Part II: Transcendental Logic [p. 50]
• Introduction the Idea of a Transcendental Logic
• I: Of Logic In General
• II: Of Transcendental Logic
• III: Of the Division of General Logic Into Analytic and Dialectic
• IV: Of the Division of Transcendental Logic Into Transcendental Analytic and Dialectic
• Division I: Transcendental Analytic In Two Books, With Their Chapters and Sections
• Book I: Analytic of Concepts
• Chapter I: Method of Discovering All Pure Concepts of the Understanding
• Section I: Of the Logical Use of the Understanding In General
• Section II: Of the Logical Function of the Understanding In Judgments [p. 70]
• Section III: Of the Pure Concepts of the Understanding, Or of the Categories
• Chapter II: Of the Deduction of the Pure Concepts of the Understanding [p. 84]
• Section I: Of the Principles of a Transcendental Deduction In General
• Section II: Of the a Priori Grounds For the Possibility of Experience
• I: Of the Synthesis of Apprehension In Intuition
• II: Of the Synthesis of Reproduction In Imagination
• III: Of the Synthesis of Recognition In Concepts [p. 103]
• IV: Preliminary Explanation of the Possibility of the Categories As Knowledge a Priori
• Section III: Of the Relation of the Understanding to Objects In General, and the Possibility of Knowing Them a Priori [p. 115]
• Book II: Analytic of Principles
• Introduction of the Transcendental Faculty of Judgment In General
• Chapter I: Of the Schematism of the Pure Concepts of the Understanding [p. 137]
• Chapter II: System of All Principles of the Pure Understanding [p. 148]
• Section I: Of the Highest Principle of All Analytical Judgments
• Section II: Of the Highest Principle of All Synthetical Judgments [p. 154]
• Section III: Systematical Representation of All Synthetical Principles of the Understanding
• I: [of the Axioms of Intuition 1 Principle of the Pure Understanding
• II: [ Anticipations of Perception
• III: [ the Analogies of Experience
• IV: The Postulates of Empirical Thought In General
• Chapter III: On the Ground of Distinction of All Subjects Into Phenomena and Noumena
• I.: Identity and Difference
• II.: Agreement and Opposition
• III.: The Internal and the External
• IV.: Matter and Form
• Note On the Amphiboly of Reflective Concepts
• Division II: Transcendental Dialectic In Two Books, With Their Chapters and Sections [p. 293]
• Introduction: 1.
• Book I: Of the Concepts of Pure Reason [p. 310]
• First Section of Ideas In General
• Second Section of Transcendental Ideas [p. 321]
• Third Section System of Transcendental Ideas [p. 333]
• Book II: Of the Dialectical Conclusions of Pure Reason
• Chapter I: Of the Paralogisms of Pure Reason [p. 341]
• Chapter II: The Antinomy of Pure Reason
• Section I: System of Cosmological Ideas
• Section II: Antithetic of Pure Reason
• Section III: Of the Interest of Reason In These Conflicts [p. 462]
• Section IV: Of the Transcendental Problems of Pure Reason, and the Absolute Necessity of Their Solution
• Section V: Sceptical Representation of the Cosmological Questions In the Four Transcendental Ideas [p. 485]
• Section VI: Transcendental Idealism As the Key to the Solution of Cosmological Dialectic
• Section VII: Critical Decision of the Cosmological Conflict of Reason With Itself
• Section VIII: The Regulative Principle of Pure Reason With Regard to the Cosmological Ideas [p. 508]
• Section IX: Of the Empirical Use of the Regulative Principle of Reason With Regard to All Cosmological Ideas
• Chapter III: The Ideal of Pure Reason
• Section I: Of the Ideal In General
• Section II: Of the Transcendental Ideal ( Prototypon Transcendentale )
• Section III: Of the Arguments of Speculative Reason In Proof of the Existence of a Supreme Being
• Section IV: Of the Impossibility of an Ontological Proof of the Existence of God [p. 592]
• Section V: Of the Impossibility of a Cosmological Proof of the Existence of God [p. 603]
• Section VI: Of the Impossibility of the Physico-theological Proof
• Section VII: Criticism of All Theology Based On Speculative Principles of Reason [p. 631]
• Chapter I: The Discipline of Pure Reason
• Section I: The Discipline of Pure Reason In Its Dogmatical Use
• Section II: The Discipline of Pure Reason In Its Polemical Use
• Section III: The Discipline of Pure Reason With Regard to Hypotheses
• Section IV: The Discipline of Pure Reason With Regard to Its Proofs
• Chapter II: The Canon of Pure Reason [p. 795]
• First Section: of the Ultimate Aim of the Pure Use of Our Reason
• Section II: Of the Ideal of the Summum Bonum As Determining the Ultimate Aim of Pure Reason
• Section III: Of Trowing, Knowing, and Believing [p. 820]
• Chapter III: The Architectonic of Pure Reason [p. 832]
• Chapter IV: The History of Pure Reason [p. 852]
• Supplement I: Motto to Second Edition
• Supplement II: Preface to the Second Edition. 1787. [p. Vii]
• Supplement III: Supplement Iv
• Supplement V
• Supplement Vi
• Supplement V
• Supplement Vi
• Supplement Vii
• Supplement Viii
• Supplement Ix
• Supplement X
• Supplement Xi
• Supplement Xii
• Supplement Xiii
• Supplement Xiv
• Supplement Xv
• Supplement Xvi a
• Supplement Xvi B
• Supplement Xvii
• Supplement Xviii
• Supplement Xix
• Supplement Xx
• Supplement Xxi
• Supplement Xxii
• Supplement Xxiii
• Supplement Xxiv
• Supplement Xxv
• Supplement Xxvi
• Supplement Xxvii
• Supplement Xxviii

PREFACE1

Our reason (Vernunft) has this peculiar fate that, with reference to one class of its knowledge, it is always troubled with questions which cannot be ignored, because they spring from the very nature of reason, and which cannot be answered, because they transcend the powers of human reason.

Nor is human reason to be blamed for this. It begins with principles which, in the course of experience, it must follow, and which are sufficiently confirmed by experience. With these again, according to the necessities of its nature, it rises higher and higher to more remote conditions. But when it perceives that in this way its work remains for ever incomplete, because the questions never cease, it finds itself constrained to take refuge in principles which exceed every possible experimental application, and nevertheless seem so unobjectionable that even ordinary common sense agrees with them. Thus, however, reason becomes involved in darkness and contradictions, from which, no doubt, it may conclude that errors must be lurking somewhere, but without being able to discover them, because the principles which it follows transcend all the limits of experience and therefore withdraw themselves from all experimental tests. It is the battle-field of these endless controversies which is called Metaphysic.

There was a time when Metaphysic held a royal place among all the sciences, and, if the will were taken for the deed, the exceeding importance of her subject might well have secured to her that place of honour. At present it is the fashion to despise Metaphysic, and the poor matron, forlorn and forsaken, complains like Hecuba, Modo maxima rerum, tot generis natisque potens — nunc trahor exul, inops (Ovid, Metam. xiii. 508).

At first the rule of Metaphysic, under the dominion of the dogmatists, was despotic. But as the laws still bore the traces of an old barbarism, intestine wars and complete anarchy broke out, and the sceptics, a kind of nomads, despising all settled culture of the land, broke up from time to time all civil society. Fortunately their number was small, and they could not prevent the old settlers from returning to cultivate the ground afresh, though without any fixed plan or agreement. Not long ago one might have thought, indeed, that all these quarrels were to have been settled and the legitimacy of her claims decided once for all through a certain physiology of the human understanding, the work of the celebrated Locke. But, though the descent of that royal pretender, traced back as it had been to the lowest mob of common experience, ought to have rendered her claims very suspicious, yet, as that genealogy turned out to be in reality a false invention, the old queen (Metaphysic) continued to maintain her claims, everything fell back into the old rotten dogmatism, and the contempt from which metaphysical science was to have been rescued, remained the same as ever. At present, after everything has been tried, so they say, and tried in vain, there reign in philosophy weariness and complete indifferentism, the mother of chaos and night in all sciences but, at the same time, the spring or, at least, the prelude of their near reform and of a new light, after an ill-applied study has rendered them dark, confused, and useless.

It is in vain to assume a kind of artificial indifferentism in respect to enquiries the object of which cannot be indifferent to human nature. Nay, those pretended indifferentists (however they may try to disguise themselves by changing scholastic terminology into popular language), if they think at all, fall back inevitably into those very metaphysical dogmas which they profess to despise. Nevertheless this indifferentism, showing itself in the very midst of the most flourishing state of all sciences, and affecting those very sciences the teachings of which, if they could be had, would be the last to be surrendered, is a phenomenon well worthy of our attention and consideration. It is clearly the result, not of the carelessness, but of the matured judgment1 of our age, which will no longer rest satisfied with the mere appearance of knowledge. It is, at the same time, a powerful appeal to reason to undertake anew the most difficult of its duties, namely, self-knowledge, and to institute a court of appeal which should protect the just rights of reason, but dismiss all groundless claims, and should do this not by means of irresponsible decrees, but according to the eternal and unalterable laws of reason. This court of appeal is no other than the Critique of Pure Reason.

I do not mean by this a criticism of books and systems, but of the faculty of reason in general, touching that whole class of knowledge which it may strive after, unassisted by experience. This must decide the question of the possibility or impossibility of metaphysic in general, and the determination of its sources, its extent, and its limits — and all this according to fixed principles.

This, the only way that was left, I have followed, and I flatter myself that I have thus removed all those errors which have hitherto brought reason, whenever it was unassisted by experience, into conflict with itself. I have not evaded its questions by pleading the insufficiency of human reason, but I have classified them according to principles, and, after showing the point where reason begins to misunderstand itself, solved them satisfactorily. It is true that the answer of those questions is not such as a dogma-enamoured curiosity might wish for, for such curiosity could not have been satisfied except by juggling tricks in which I am no adept. But this was not the intention of the natural destiny of our reason, and it became the duty of philosophy to remove the deception which arose from a false interpretation, even though many a vaunted and cherished dream should vanish at the same time. In this work I have chiefly aimed at completeness, and I venture to maintain that there ought not to be one single metaphysical problem that has not been solved here, or to the solution of which the key at least has not been supplied. In fact Pure Reason is so perfect a unity that, if its principle should prove insufficient to answer any one of the many questions started by its very nature, one might throw it away altogether, as insufficient to answer the other questions with perfect certainty.

While I am saying this I fancy I observe in the face of my readers an expression of indignation, mixed with contempt, at pretensions apparently so self-glorious and extravagant; and yet they are in reality far more moderate than those made by the writer of the commonest essay professing to prove the simple nature of the soul or the necessity of a first beginning of the world. For, while he pretends to extend human knowledge beyond the limits of all possible experience, I confess most humbly that this is entirely beyond my power. I mean only to treat of reason and its pure thinking, a knowledge of which is not very far to seek, considering that it is to be found within myself. Common logic gives an instance how all the simple acts of reason can be enumerated completely and systematically. Only between the common logic and my work there is this difference, that my question is, — what can we hope to achieve with reason, when all the material and assistance of experience is taken away?

So much with regard to the completeness in our laying hold of every single object, and the thoroughness in our laying hold of all objects, as the material of our critical enquiries — a completeness and thoroughness determined, not by a casual idea, but by the nature of our knowledge itself.

Besides this, certainty and clearness with regard to form are two essential demands that may very properly be addressed to an author who ventures on so slippery an undertaking.

First, with regard to certainty, I have pronounced judgment against myself by saying that in this kind of enquiries it is in no way permissible to propound mere opinions, and that everything looking like a hypothesis is counterband, that must not be offered for sale at however low a price, but must, as soon as it has been discovered, be confiscated. For every kind of knowledge which professes to be certain a priori, proclaims itself that it means to be taken for absolutely necessary. And this applies, therefore, still more to a definition of all pure knowledge a priori, which is to be the measure, and therefore also an example, of all apodictic philosophical certainty. Whether I have fulfilled what I have here undertaken to do, must be left to the judgment of the reader; for it only behoves the author to propound his arguments, and not to determine beforehand the effect which they ought to produce on his judges. But, in order to prevent any unnecessary weakening of those arguments, he may be allowed to point out himself certain passages which, though they refer to collateral objects only, might occasion some mistrust, and thus to counteract in time the influence which the least hesitation of the reader in respect to these minor points might exercise with regard to the principal object.

I know of no enquiries which are more important for determining that faculty which we call understanding (Verstand), and for fixing its rules and its limits, than those in the Second Chapter of my Transcendental Analytic, under the title of ‘Deduction of the Pure Concepts of the Understanding.’ They have given me the greatest but, I hope, not altogether useless trouble. This enquiry, which rests on a deep foundation, has two sides. The one refers to the objects of the pure understanding, and is intended to show and explain the objective value of its concepts a priori. It is, therefore, of essential importance for my purposes. The other is intended to enquire into the pure understanding itself, its possibility, and the powers of knowledge on which it rests, therefore its subjective character; a subject which, though important for my principal object, yet forms no essential part of it, because my principal problem is and remains, What and how much may understanding (Verstand) and reason (Vernunft) know without all experience? and not, How is the faculty of thought possible? The latter would be an enquiry into a cause of a given effect; it would, therefore, be of the nature of an hypothesis (though, as I shall show elsewhere, this is not quite so); and it might seem as if I had here allowed myself to propound a mere opinion, leaving the reader free to hold another opinion also. I therefore warn the reader, in case my subjective deduction should not produce that complete conviction which I expect, that the objective deduction, in which I am here chiefly concerned, must still retain its full strength. For this, what has been said on pp. 82, 83 (92, 93) may possibly by itself be sufficient.

Secondly, as to clearness, the reader has a right to demand not only what may be called logical or discursive clearness, which is based on concepts, but also what may be called æsthetic or intuitive clearness produced by intuitions, i.e. by examples and concrete illustrations. With regard to the former I have made ample provision. That arose from the very nature of my purpose, but it became at the same time the reason why I could not fully satisfy the latter, if not absolute, yet very just claim. Nearly through the whole of my work I have felt doubtful what to do. Examples and illustrations seemed always to be necessary, and therefore found their way into the first sketch of my work. But I soon perceived the magnitude of my task and the number of objects I should have to treat; and, when I saw that even in their driest scholastic form they would considerably swell my book, I did not consider it expedient to extend it still further through examples and illustrations required for popular purposes only. This work can never satisfy the popular taste, and the few who know, do not require that help which, though it is always welcome, yet might here have defeated its very purpose. The Abbé Terrasson1 writes indeed that, if we measured the greatness of a book, not by the number of its pages, but by the time we require for mastering it, many a book might be said to be much shorter, if it were not so short. But, on the other hand, if we ask how a complicated, yet in principle coherent whole of speculative thought can best be rendered intelligible, we might be equally justified in saying that many a book would have been more intelligible, if it had not tried to be so very intelligible. For the helps to clearness, though they may be missed2 with regard to details, often distract with regard to the whole. The reader does not arrive quickly enough at a survey of the whole, because the bright colours of illustrations hide and distort the articulation and concatenation of the whole system, which, after all, if we want to judge of its unity and sufficiency, are more important than anything else.

Surely it should be an attraction to the reader if he is asked to join his own efforts with those of the author in order to carry out a great and important work, according to the plan here proposed, in a complete and lasting manner. Metaphysic, according to the definitions here given, is the only one of all sciences which, through a small but united effort, may count on such completeness in a short time, so that nothing will remain for posterity but to arrange everything according to its own views for didactic purposes, without being able to add anything to the subject itself. For it is in reality nothing but an inventory of all our possessions acquired through Pure Reason, systematically arranged. Nothing can escape us, because whatever reason produces entirely out of itself, cannot hide itself, but is brought to light by reason itself, so soon as the common principle has been discovered. This absolute completeness is rendered not only possible, but necessary, through the perfect unity of this kind of knowledge, all derived from pure concepts, without any influence from experience, or from special intuitions leading to a definite kind of experience, that might serve to enlarge and increase it. Tecum habita et noris quam sit tibi curta supellex (Persius, Sat. iv. 52).

Such a system of pure (speculative) reason I hope myself to produce under the title of ‘Metaphysic of Nature.’ It will not be half so large, yet infinitely richer than this Critique of Pure Reason, which has, first of all, to discover its source, nay, the conditions of its possibility, in fact, to clear and level a soil quite overgrown with weeds. Here I expect from my readers the patience and impartiality of a judge, there the goodwill and aid of a fellow-worker. For however completely all the principles of the system have been propounded in my Critique, the completeness of the whole system requires also that no derivative concepts should be omitted, such as cannot be found out by an estimate a priori, but have to be discovered step by step. There the synthesis of concepts has been exhausted, here it will be requisite to do the same for their analysis, a task which is easy and an amusement rather than a labour.

I have only a few words to add with respect to the printing of my book. As the beginning had been delayed, I was not able to see the clean sheets of more than about half of it. I now find some misprints, though they do not spoil the sense, except on p. 379, line 4 from below, where specific should be used instead of sceptic. The antinomy of pure reason from p. 425 to p. 461 has been arranged in a tabular form, so that all that belongs to the thesis stands on the left, what belongs to the antithesis on the right side. I did this in order that thesis and antithesis might be more easily compared.

[1 ]This preface is left out in later editions, and replaced by a new preface; see Supplement II, page 688.

[1 ]We often hear complaints against the shallowness of thought in our own time, and the decay of sound knowledge. But I do not see that sciences which rest on a solid foundation, such as mathematics, physics, etc., deserve this reproach in the least. On the contrary, they maintain their old reputation of solidity, and with regard to physics, even surpass it. The same spirit would manifest itself in other branches of knowledge, if only their principles had first been properly determined. Till that is done, indifferentism and doubt, and ultimately severe criticism, are rather signs of honest thought. Our age is, in every sense of the word, the age of criticism, and everything must submit to it. Religion, on the strength of its sanctity, and law, on the strength of its majesty, try to withdraw themselves from it; but by so doing they arouse just suspicions, and cannot claim that sincere respect which reason pays to those only who have been able to stand its free and open examination.

[1 ]Terrasson, Philosophie nach ihrem allgemeinen Einflusse auf alle Gegenstände des Geistes und der Sitten, Berlin, 1762, p. 117.

[2 ]Rosenkranz and others change fehlen into helfen, without necessity, I think.