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

I

THE IDEA OF TRANSCENDENTAL PHILOSOPHY

[Experience1 is no doubt the first product of our understanding, while employed in fashioning the raw material of our sensations. It is therefore our first instruction, and in its progress so rich in new lessons that the chain of all future generations will never be in want of new information that may be gathered on that field. Nevertheless, experience is by no means the only field to which our understanding can be confined. Experience tells us what is, but not that it must be necessarily as it is, and not otherwise. It therefore never gives us any really general truths, and our reason, which is particularly anxious for that class of knowledge, is roused by it rather than satisfied. General truths, which at the same time [p. 2] bear the character of an inward necessity, must be independent of experience, — clear and certain by themselves. They are therefore called knowledge a priori, while what is simply taken from experience is said to be, in ordinary parlance, known a posteriori or empirically only.

Now it appears, and this is extremely curious, that even with our experiences different kinds of knowledge are mixed up, which must have their origin a priori, and which perhaps serve only to produce a certain connection between our sensuous representations. For even if we remove from experience everything that belongs to the senses, there remain nevertheless certain original concepts, and certain judgments derived from them, which must have had their origin entirely a priori, and independent of all experience, because it is owing to them that we are able, or imagine we are able, to predicate more of the objects of our senses than can be learnt from mere experience, and that our propositions contain real generality and strict necessity, such as mere empirical knowledge can never supply.]

But1 what is still more extraordinary is this, that certain kinds of knowledge leave the field of all possible [p. 3] experience, and seem to enlarge the sphere of our judgments beyond the limits of experience by means of concepts to which experience can never supply any corresponding objects.

And it is in this very kind of knowledge which transcends the world of the senses, and where experience can neither guide nor correct us, that reason prosecutes its investigations, which by their importance we consider far more excellent and by their tendency far more elevated than anything the understanding can find in the sphere of phenomena. Nay, we risk rather anything, even at the peril of error, than that we should surrender such investigations, either on the ground of their uncertainty, or from any feeling of indifference or contempt.1

Now it might seem natural that, after we have left the solid ground of experience, we should not at once proceed to erect an edifice with knowledge which we possess without knowing whence it came, and trust to principles the origin of which is unknown, without having made sure of the safety of the foundations by means of careful examination. It would seem natural, I say, that philosophers should first of all have asked the question how the mere understanding could arrive at all this knowledge a priori, and what extent, what truth, and what value it could possess. If we take natural [p. 4] to mean what is just and reasonable, then indeed nothing could be more natural. But if we understand by natural what takes place ordinarily, then, on the contrary, nothing is more natural and more intelligible than that this examination should have been neglected for so long a time. For one part of this knowledge, namely, the mathematical, has always been in possession of perfect trustworthiness; and thus produces a favourable presumption with regard to other parts also, although these may be of a totally different nature. Besides, once beyond the precincts of experience, and we are certain that experience can never contradict us, while the charm of enlarging our knowledge is so great that nothing will stop our progress until we encounter a clear contradiction. This can be avoided if only we are cautious in our imaginations, which nevertheless remain what they are, imaginations only. How far we can advance independent of all experience in a priori knowledge is shown by the brilliant example of mathematics. It is true they deal with objects and knowledge so far only as they can be represented in intuition. But this is easily overlooked, because that intuition itself may be given a priori, and be difficult to distinguish from a pure concept. Thus inspirited [p. 5] by a splendid proof of the power of reason, the desire of enlarging our knowledge sees no limits. The light dove, piercing in her easy flight the air and perceiving its resistance, imagines that flight would be easier still in empty space. It was thus that Plato left the world of sense, as opposing so many hindrances to our understanding, and ventured beyond on the wings of his ideas into the empty space of pure understanding. He did not perceive that he was making no progress by these endeavours, because he had no resistance as a fulcrum on which to rest or to apply his powers, in order to cause the understanding to advance. It is indeed a very common fate of human reason first of all to finish its speculative edifice as soon as possible, and then only to enquire whether the foundation be sure. Then all sorts of excuses are made in order to assure us as to its solidity, or to decline altogether such a late and dangerous enquiry. The reason why during the time of building we feel free from all anxiety and suspicion and believe in the apparent solidity of our foundation, is this: — A great, perhaps the greatest portion of what our reason finds to do consists in the analysis of our concepts of objects. This gives us a great deal of knowledge which, though it consists in no more man in simplifications and explanations of [p. 6] what is comprehended in our concepts (though in a confused manner), is yet considered as equal, at least in form, to new knowledge. It only separates and arranges our concepts, it does not enlarge them in matter or contents. As by this process we gain a kind of real knowledge a priori, which progresses safely and usefully, it happens that our reason, without being aware of it, appropriates under that pretence propositions of a totally different character, adding to given concepts new and strange ones a priori, without knowing whence they come, nay without even thinking of such a question. I shall therefore at the very outset treat of the distinction between these two kinds of knowledge.

Of the Distinction between Analytical and Synthetical Judgments

In all judgments in which there is a relation between subject and predicate (I speak of affirmative judgments only, the application to negative ones being easy), that relation can be of two kinds. Either the predicate B belongs to the subject A as something contained (though covertly) in the concept A; or B lies outside the sphere of the concept A, though somehow connected with it. In the former case I call the judgment analytical, in the latter synthetical. Analytical judgments (affirmative) are therefore those in which the connection of the [p. 7] predicate with the subject is conceived through identity, while others in which that connection is conceived without identity, may be called synthetical. The former might be called illustrating, the latter expanding judgments, because in the former nothing is added by the predicate to the concept of the subject, but the concept is only divided into its constituent concepts which were always conceived as existing within it, though confusedly; while the latter add to the concept of the subject a predicate not conceived as existing within it, and not to be extracted from it by any process of mere analysis. If I say, for instance, All bodies are extended, this is an analytical judgment. I need not go beyond the concept connected with the name of body, in order to find that extension is connected with it. I have only to analyse that concept and become conscious of the manifold elements always contained in it, in order to find that predicate. This is therefore an analytical judgment. But if I say, All bodies are heavy, the predicate is something quite different from what I think as the mere concept of body. The addition of such a predicate gives us a synthetical judgment.

[It becomes clear from this,1

[1. That our knowledge is in no way extended by analytical judgments, but that all they effect is [p. 8] to put the concepts which we possess into better order and render them more intelligible.

2. That in synthetical judgments I must have besides the concept of the subject something else (x) on which the understanding relies in order to know that a predicate, not contained in the concept, nevertheless belongs to it.

In empirical judgments this causes no difficulty, because this x is here simply the complete experience of an object which I conceive by the concept A, that concept forming one part only of my experience. For though I do not include the predicate of gravity in the general concept of body, that concept nevertheless indicates the complete experience through one of its parts, so that I may add other parts also of the same experience, all belonging to that concept. I may first, by an analytical process, realise the concept of body through the predicates of extension, impermeability, form, etc., all of which are contained in it. Afterwards I expand my knowledge, and looking back to the experience from which my concept of body was abstracted, I find gravity always connected with the before-mentioned predicates. Experience therefore is the x which lies beyond the concept A, and on which rests the possibility of a synthesis of the predicate of gravity B with the concept A.]

In synthetical judgments a priori, however, that [p. 9] help is entirely wanting. If I want to go beyond the concept A in order to find another concept B connected with it, where is there anything on which I may rest and through which a synthesis might become possible, considering that I cannot have the advantage of looking about in the field of experience? Take the proposition that all which happens has its cause. In the concept of something that happens I no doubt conceive of something existing preceded by time, and from this certain analytical judgments may be deduced. But the concept of cause is entirely outside that concept, and indicates something different from that which happens, and is by no means contained in that representation. How can I venture then to predicate of that which happens something totally different from it, and to represent the concept of cause, though not contained in it, as belonging to it, and belonging to it by necessity? What is here the unknown x, on which the understanding may rest in order to find beyond the concept A a foreign predicate B, which nevertheless is believed to be connected with it? It cannot be experience, because the proposition that all which happens has its cause represents this second predicate as added to the subject not only with greater generality than experience can ever supply, but also with a character of necessity, and therefore purely a priori, and based on concepts. All our speculative knowledge a priori aims at and rests on such synthetical, i.e. expanding propositions, for [p. 10] the analytical are no doubt very important and necessary, yet only in order to arrive at that clearness of concepts which is requisite for a safe and wide synthesis, serving as a really new addition to what we possess already.

[We1 have here a certain mystery2 before us, which must be cleared up before any advance into the unlimited field of a pure knowledge of the understanding can become safe and trustworthy. We must discover on the largest scale the ground of the possibility of synthetical judgments a priori; we must understand the conditions which render every class of them possible, and endeavour not only to indicate in a sketchy outline, but to define in its fulness and practical completeness, the whole of that knowledge, which forms a class by itself, systematically arranged according to its original sources, its divisions, its extent and its limits. So much for the present with regard to the peculiar character of synthetical judgments.]

It will now be seen how there can be a special [p. 11] science serving as a critique of pure reason. [Every kind of knowledge is called pure, if not mixed with anything heterogeneous. But more particularly is that knowledge called absolutely pure, which is not mixed up with any experience or sensation, and is therefore possible entirely a priori.] Reason is the faculty which supplies the principles of knowledge a priori. Pure reason therefore is that faculty which supplies the principles of knowing anything entirely a priori. An Organum of pure reason ought to comprehend all the principles by which pure knowledge a priori can be acquired and fully established. A complete application of such an Organum would give us a System of Pure Reason. But as that would be a difficult task, and as at present it is still doubtful whether and when such an expansion of our knowledge is here possible, we may look on a mere criticism of pure reason, its sources and limits, as a kind of preparation for a complete system of pure reason. It should be called a critique, not a doctrine, of pure reason. Its usefulness would be negative only, serving for a purging rather than for an expansion of our reason, and, what after all is a considerable gain, guarding reason against errors.

I call all knowledge transcendental which is occupied not so much with objects, as with our a priori concepts of objects.1 A system of such concepts might be [p. 12] called Transcendental Philosophy. But for the present this is again too great an undertaking. We should have to treat therein completely both of analytical knowledge, and of synthetical knowledge a priori, which is more than we intend to do, being satisfied to carry on the analysis so far only as is indispensably necessary in order to recognise in their whole extent the principles of synthesis a priori which alone concern us. This investigation which should be called a transcendental critique, but not a systematic doctrine, is all we are occupied with at present. It is not meant to extend our knowledge, but only to rectify it, and to become the test of the value of all a priori knowledge. Such a critique therefore is a preparation for a New Organum, or, if that should not be possible, for a Canon at least, according to which hereafter a complete system of a philosophy of pure reason, whether it serve for an expansion or merely for a limitation of it, may be carried out, both analytically and synthetically. That such a system is possible, nay that it need not be so comprehensive as to prevent the hope of its completion, may be gathered from the fact that it would have to deal, not with the nature of things, which is endless, but with the understanding which judges of the nature of [p. 13] things, and this again so far only as its knowledge a priori is concerned. Whatever the understanding possesses a priori, as it has not to be looked for without, can hardly escape our notice, nor is there any reason to suppose that it will prove too extensive for a complete inventory, and for such a valuation as shall assign to it its true merits or demerits.1

[1 ]The beginning of this Introduction down to ‘But what is still more extraordinary,’ is left out in the Second Edition. Instead of it Supplement IV.

[1 ]The Second Edition gives here a new heading: — III, Philosophy requires a science to determine the possibility, the principles, and the extent of all cognitions a priori.

[1 ]The Second Edition adds here: ‘These inevitable problems of pure reason itself are, God, Freedom, and Immortality. The science which with all its apparatus is really intended for the solution of these problems, is called Metaphysic. Its procedure is at first dogmatic, i.e. unchecked by a previous examination of what reason can and cannot do, before it engages confidently in so arduous an undertaking.’

[1 ]These two paragraphs to ‘In synthetical judgments a priori, however,’ are left out in the Second Edition, and replaced by Supplement V.

[1 ]This paragraph left out in the Second Edition, and replaced by Supplement VI.

[2 ]If any of the ancients had ever thought of asking this question, this alone would have formed a powerful barrier against all systems of pure reason to the present day, and would have saved many vain attempts undertaken blindly and without a true knowledge of the subject in hand.

[1 ]‘As with our manner of knowing objects, so far as this is meant to be possible a priori.’ Second Edition.

[1 ]Here follows Supplement VII in Second Edition.