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

VI

The General Problem of Pure Reason

Much is gained if we are able to bring a number of investigations under the formula of one single problem. For we thus not only facilitate our own work by defining it accurately, but enable also everybody else who likes to examine it to form a judgment, whether we have really done justice to our purpose or not. Now the real problem of pure reason is contained in the question, How are synthetical judgments a priori possible?

That metaphysic has hitherto remained in so vacillating a state of ignorance and contradiction is entirely due to people not having thought sooner of this problem, or perhaps even of a distinction between analytical and synthetical judgments. The solution of this problem, or a sufficient proof that a possibility which is to be explained does in reality not exist at all, is the question of life or death to metaphysic. David Hume, who among all philosophers approached nearest to that problem, though he was far from conceiving it with sufficient definiteness and universality, confining his attention only to the synthetical proposition of the connection of an effect with its causes (principium causalitatis), arrived at the conclusion that such a proposition a priori is entirely impossible. According to his conclusions, everything which we call metaphysic would turn out to be a mere delusion of reason, fancying that it knows by itself what in reality is only borrowed from experience, and has assumed by mere habit the appearance of necessity. If he had grasped our problem in all its universality, he would never have thought of an assertion which destroys all pure philosophy, because he would have perceived that, according to his argument, no pure mathematical science was possible either, on account of its certainly containing synthetical propositions a priori; and from such an assertion his good sense would probably have saved him.

On the solution of our problem depends, at the same time, the possibility of the pure employment of reason, in establishing and carrying out all sciences which contain a theoretical knowledge a priori of objects, i.e. the answer to the questions

How is pure mathematical science possible?

How is pure natural science possible?

As these sciences really exist, it is quite proper to ask, How they are possible? for that they must be possible, is proved by their reality.1

But as to metaphysic, the bad progress which it has hitherto made, and the impossibility of asserting of any of the metaphysical systems yet brought forward that it really exists, so far as its essential aim is concerned, must fill every one with doubts as to its possibility.

Yet, in a certain sense, this kind of knowledge also must be looked upon as given, and though not as a science, yet as a natural disposition (metaphysica naturalis) metaphysic is real. For human reason, without being moved merely by the conceit of omniscience, advances irresistibly, and urged on by its own need, to questions such as cannot be answered by any empirical employment of reason, or by principles thence derived, so that we may really say, that all men, as soon as their reason became ripe for speculation, have at all times possessed some kind of metaphysic, and will always continue to possess it. And now it will also have to answer the question

How is metaphysic possible, as a natural disposition? that is how does the nature of universal human reason give rise to questions which pure reason proposes to itself, and which it is urged on by its own need to answer as well as it can?

As, however, all attempts which have hitherto been made at answering these natural questions (for instance, whether the world has a beginning, or exists from all eternity) have always led to inevitable contradictions, we cannot rest satisfied with the mere natural disposition to metaphysic, that is, with the pure faculty of reason itself, from which some kind of metaphysic (whatever it may be) always arises; but it must be possible to arrive with it at some certainty as to our either knowing or not knowing its objects; that is, we must either decide that we can judge of the objects of these questions, or of the power or want of power of reason, in deciding anything upon them, — therefore that we can either enlarge our pure reason with certainty, or that we have to impose on it fixed and firm limits. This last question, which arises out of the former more general problem, would properly assume this form,

How is metaphysic possible, as a science?

The critique of reason leads, therefore, necessarily, to true science, while its dogmatical use, without criticism, lands us in groundless assertions, to which others, equally specious, can always be opposed, that is, in scepticism.

Nor need this science be very formidable by its great prolixity, for it has not to deal with the objects of reason, the variety of which is infinite, but with reason only, and with problems, suggested by reason and placed before it, not by the nature of things, which are different from it, but by its own nature; so that, if reason has only first completely understood its own power, with reference to objects given to it in experience, it will have no difficulty in determining completely and safely the extent and limits of its attempted application beyond the limits of all experience.

We may and must therefore regard all attempts which have hitherto been made at building up a metaphysic dogmatically, as non-avenu. For the mere analysis of the concepts that dwell in our reason a priori, which has been attempted in one or other of those metaphysical systems, is by no means the aim, but only a preparation for true metaphysic, namely, the answer to the question, how we can enlarge our knowledge a priori synthetically; nay, it is utterly useless for that purpose, because it only shows what is contained in those concepts, but not by what process a priori we arrive at them, in order thus to determine the validity of their employment with reference to all objects of knowledge in general. Nor does it require much self-denial to give up these pretensions, considering that the undeniable and, in the dogmatic procedure, inevitable contradictions of reason with itself, have long deprived every system of metaphysic of all authority. More firmness will be required in order not to be deterred by difficulties from within and resistance from without, from trying to advance a science, indispensable to human reason (a science of which we may lop off every branch, but will never be able to destroy the root), by a treatment entirely opposed to all former treatments, which promises, at last, to ensure the successful and fruitful growth of metaphysical science.

[1 ]One might doubt this with regard to pure natural science; but one has only to consider the different propositions which stand at the beginning of real (empirical) physical science, those, for example, relating to the permanence of the same quantity of matter to the vis inertiae, the equality of action and reaction, etc., in order to become convinced that they constitute a physica pura, or rationalis, which well deserves to stand by itself as an independent science, in its whole extent, whether narrow or wide.