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

CHAPTER III

ON THE GROUND OF DISTINCTION OF ALL SUBJECTS INTO PHENOMENA AND NOUMENA

We have now not only traversed the whole domain of the pure understanding, and carefully examined each part of it, but we have also measured its extent, and assigned to everything in it its proper place. This domain, however, is an island and enclosed by nature itself within limits that can never be changed. It is the country of truth (a very attractive name), but surrounded by a wide and stormy ocean, the true home of illusion, where many a fog bank and ice that soon melts away tempt us to believe in new lands, while constantly deceiving the adventurous mariner with vain hopes, and involving [p. 236] him in adventures which he can never leave, and yet can never bring to an end. Before we venture ourselves on this sea, in order to explore it on every side, and to find out whether anything is to be hoped for there, it will be useful to glance once more at the map of that country which we are about to leave, and to ask ourselves, first, whether we might not be content with what it contains, nay, whether we must not be content with it, supposing that there is no solid ground anywhere else on which we could settle; secondly, by what title we possess even that domain, and may consider ourselves safe against all hostile claims. Although we have sufficiently answered these questions in the course of the analytic, a summary recapitulation of their solutions may help to strengthen our conviction, by uniting all arguments in one point.

We have seen that the understanding possesses everything which it draws from itself, without borrowing from experience, for no other purpose but for experience. The principles of the pure understanding, whether constitutive a priori (as the mathematical) or simply relative (as the dynamical), contain nothing but, as it were, the pure schema of possible experience; for that experience [p. 237] derives its unity from that synthetical unity alone which the understanding originally and spontaneously imparts to the synthesis of imagination, with reference to apperception, and to which all phenomena, as data of a possible knowledge, must conform a priori. But although these rules of the understanding are not only true a priori, but the very source of all truth, that is, of the agreement of our knowledge with objects, because containing the conditions of the possibility of experience, as the complete sphere of all knowledge in which objects can be given to us, nevertheless we do not seem to be content with hearing only what is true, but want to know a great deal more. If therefore this critical investigation does not teach us any more than what, even without such subtle researches, we should have practised ourselves in the purely empirical use of the understanding, it would seem as if the advantages derived from it were hardly worth the labour. One might reply that nothing would be more prejudicial to the enlargement of our knowledge than that curiosity which, before entering upon any researches, wishes to know beforehand the advantages likely to accrue from them, though quite unable as yet to form the least conception of such advantages, even though they were placed before our eyes. There is, however, one advantage in this transcendental investigation which can be rendered intelligible, [p. 238] nay, even attractive to the most troublesome and reluctant apprentice, namely this, that the understanding confined to its empirical use only and unconcerned with regard to the sources of its own knowledge, may no doubt fare very well in other respects, but can never determine for itself the limits of its own use and know what is inside or outside its own sphere. It is for that purpose that such profound investigations are required as we have just instituted. If the understanding cannot decide whether certain questions lie within its own horizon or not, it can never feel certain with regard to its claims and possessions, but must be prepared for many humiliating corrections, when constantly transgressing, as it certainly will, the limits of its own domain, and losing itself in follies and fancies.

That the understanding cannot make any but an empirical, and never a transcendental, use of all its principles a priori, nay, of all its concepts, is a proposition which, if thoroughly understood, leads indeed to most important consequences. What we call the transcendental use of a concept in any proposition is its being referred to things in general and to things by themselves, while its empirical use refers to phenomena only, that is, to objects of a possible experience. That the latter use alone is admissible will be clear from the following considerations. [p. 239] What is required for every concept is, first, the logical form of a concept (of thought) in general; and, secondly, the possibility of an object to which it refers. Without the latter, it has no sense, and is entirely empty, though it may still contain the logical function by which a concept can be formed out of any data. The only way in which an object can be given to a concept is in intuition, and though a pure intuition is possible a priori and before the object, yet even that pure intuition can receive its object, and with it its objective validity, by an empirical intuition only, of which it is itself nothing but the form. All concepts, therefore, and with them all principles, though they may be possible a priori, refer nevertheless to empirical intuitions, that is, to data of a possible experience. Without this, they can claim no objective validity, but are a mere play, whether of the imagination or of the understanding with their respective representations. Let us take the concepts of mathematics as an example, and, first, with regard to pure intuitions. Although such principles as ‘space has three dimensions,’ ‘between two points there can be only one straight line,’ as well as the representation of the object with which that science is occupied, may be produced in the mind a priori, they would have no meaning, if we were not able at all times [p. 240] to show their meaning as applied to phenomena (empirical objects). It is for this reason that an abstract concept is required to be made sensuous, that is, that its corresponding object is required to be shown in intuition, because, without this, the concept (as people say) is without sense, that is, without meaning. Mathematics fulfil this requirement by the construction of the figure, which is a phenomenon present to the senses (although constructed a priori). In the same science the concept of quantity finds its support and sense in number; and this in turn in the fingers, the beads of the abacus, or in strokes and points which can be presented to the eyes. The concept itself was produced a priori, together with all the synthetical principles or formulas which can be derived from such concepts; but their use and their relation to objects can nowhere be found except in experience, of which those concepts contain a priori the (formal) possibility only.

That this is the case with all categories and with all the principles drawn from them, becomes evident from the fact that we could not define any one of them (really, that is, make conceivable the possibility of their object),1 without at once having recourse to the conditions of sensibility or the form of phenomena, to which, as their only possible objects, these categories must necessarily be restricted, it being impossible, if we take away [p. 241] these conditions, to assign to them any meaning, that is, any relation to an object, or to make it intelligible to ourselves by an example what kind of thing could be intended by such concepts.

[When representing the table of the categories, we dispensed with the definition of every one of them, because at that time it seemed unnecessary for our purpose, which concerned their synthetical use only, and because entailing responsibilities which we were not bound to incur. This was not a mere excuse, but a very important prudential rule, viz. not to rush into definitions, and to attempt or pretend completeness or precision in the definition of a concept, when one or other of its characteristic marks is sufficient without a complete enumeration of all that constitute the whole concept. Now, however, we can perceive that this caution had even a deeper ground, namely, that we could not have defined them, even if we had wished;1 for, if we remove all conditions of [p. 242] sensibility, which distinguish them as the concepts of a possible empirical use, and treat them as concepts of things in general (therefore as of transcendental use), nothing remains but to regard the logical function in judgments as the condition of the possibility of the things themselves, without the slightest indication as to where they could have their application and their object, or how they could have any meaning or objective validity in the pure understanding, apart from sensibility.]2

No one can explain the concept of quantity in general, except, it may be, by saying that it is the determination of an object, by which we may know how many times the one is supposed to exist in it. But this ‘how many times’ is based on successive repetition, that is on time, and on the synthesis in it of the homogeneous.

Reality, again, can only be explained in opposition to a negation, if we think of time (as containing all being) being either filled or empty.

Were I to leave out permanence (which means existence at all times), nothing would remain of my concept of substance but the logical representation of a subject which I think I can realise by imagining something which is a subject only, without [p. 243] being a predicate of anything. But in this case we should not only be ignorant of all conditions under which this logical distinction could belong to anything, but we should be unable to make any use of it or draw any conclusions from it, because no object is thus determined for the use of this concept, and no one can tell whether such a concept has any meaning at all.

Of the concept of cause also (if I leave out time, in which something follows on something else by rule) I should find no more in the pure category than that it is something which enables us to conclude the existence of something else, so that it would not only be impossible to distinguish cause and effect from each other, but the concept of cause would possess no indication as to how it can be applied to any object, because, in order to form any such conclusion, certain conditions require to be known of which the concept itself tells us nothing. The so-called principle that everything contingent has a cause, comes no doubt before us with great solemnity and self-assumed dignity. But, if I ask what you understand by contingent and you answer, something of which the non-existence is possible, I should be glad to know how you can recognise this possibility of non-existence, if you do not represent to yourselves, in the series of phenomena, some kind of succession, and in it an existence that follows upon non-existence (or vice versa), and consequently a change? To say that the non-existence of a thing is not self-contradictory [p. 244] is but a lame appeal to a logical condition which, though it is necessary for the concept, yet is by no means sufficient for its real possibility. I can perfectly well remove in thought every existing substance, without contradicting myself, but I can by no means conclude from this as to its objective contingency in its existence, that is, the possibility of its non-existence in itself.

As regards the concept of community, it is easy to see that, as the pure categories of substance and causality admit of no explanation that would determine their object, neither could such an explanation apply to the reciprocal causality in the relation of substances to each other (commercium).

As to possibility, existence, and necessity, no one has yet been able to explain them, except by a manifest tautology, so long as their definition is to be exclusively drawn from the pure understanding. To substitute the transcendental possibility of things (when an object corresponds to a concept) for the logical possibility of the concept (when the concept does not contradict itself) is a quibble such as could deceive and satisfy the inexperienced only.

[It seems to be something strange and even illogical1 that there should be a concept which must have a meaning, and yet is incapable of any explanation. But the case of these categories is peculiar, because it is only by means of the general sensuous condition that they can acquire a definite meaning, and a reference to any objects. That condition being [p. 245] left out in the pure category, it follows that it can contain nothing but the logical function by which the manifold is brought into a concept. By means of this function, that is, the pure form of the concept, nothing can be known nor distinguished as to the object belonging to it, because the sensuous condition, under which alone objects can belong to it, has been removed. Thus we see that the categories require, besides the pure concept of the understanding, certain determinations of their application to sensibility in general (schemata). Without them, they would not be concepts by which an object can be known and distinguished from other objects, but only so many ways of thinking an object for possible intuitions, and giving to it, according to one of the functions of the understanding, its meaning (certain requisite conditions being given). They are needed to define an object, and cannot therefore be defined themselves. The logical functions of judgments in general, namely, unity and plurality, assertion and negation, subject and predicate, cannot be defined without arguing in a circle, because the definition would itself be a judgment and contain these very functions. The pure categories are nothing but representations of things in general, so far as the manifold in intuition must be thought by one or the other of these functions. Thus, magnitude is the determination which can [only be thought by a judgment possessing [p. 246] quantity (judicium commune); reality, the determination which can only be thought by an affirmative judgment; while substance is that which, in regard to intuition, must be the last subject of all other determinations. With all this it remains perfectly undetermined, what kind of things they may be with regard to which we have to use one rather than another of these functions, so that, without the condition of sensuous intuition, for which they supply the synthesis, the categories have no relation to any definite object, cannot define any object, and consequently have not in themselves the validity of objective concepts.]

From this it follows incontestably, that the pure concepts of the understanding never admit of a transcendental, but only of an empirical use, and that the principles of the pure understanding can only be referred, as general conditions of a possible experience, to objects of the senses, never to things by themselves (without regard to the manner in which we have to look at them).

Transcendental Analytic has therefore yielded us this important result, that the understanding a priori can never do more than anticipate the form of a possible experience; and as nothing can be an object of experience except the phenomenon, it follows that the understanding can never go beyond the limits of sensibility, within which alone objects are given to us. Its principles are principles [p. 247] for the exhibition of phenomena only; and the proud name of Ontology, which presumes to supply in a systematic form different kinds of synthetical knowledge a priori of things by themselves (for instance the principle of causality), must be replaced by the more modest name of a mere Analytic of the pure understanding.

Thought is the act of referring a given intuition to an object. If the mode of such intuition is not given, the object is called transcendental, and the concept of the understanding admits then of a transcendental use only, in producing a unity in the thought of the manifold in general. A pure category therefore, in which every condition of sensuous intuition, the only one that is possible for us, is left out, cannot determine an object, but only the thought of an object in general, according to different modes. Now, if we want to use a concept, we require in addition some function of the faculty of judgment, by which an object is subsumed under a concept, consequently the at least formal condition under which something can be given in intuition. If this condition of the faculty of judgment (schema) is wanting, all subsumption is impossible, because nothing is given that could be subsumed under the concept. The purely transcendental use of categories therefore is in reality of no use at all, and has no definite or even, with regard to its form only, definable object. Hence it follows that a pure category is not fit for any [p. 248] synthetical a priori principle, and that the principles of the pure understanding admit of empirical only, never of transcendental application, nay, that no synthetical principles a priori are possible beyond the field of possible experience.

It might therefore be advisable to express ourselves in the following way: the pure categories, without the formal conditions of sensibility, have a transcendental character only, but do not admit of any transcendental use, because such use in itself is impossible, as the categories are deprived of all the conditions of being used in judgments, that is, of the formal conditions of the subsumption of any possible object under these concepts. As therefore (as pure categories) they are not meant to be used empirically, and cannot be used transcendentally, they admit, if separated from sensibility, of no use at all; that is, they cannot be applied to any possible object, and are nothing but the pure form of the use of the understanding with reference to objects in general, and of thought, without ever enabling us to think or determine any object by their means alone.

[Appearances,1 so far as they are thought as objects under the unity of the categories, are called phenomena. But if I admit things which are objects of the [p. 249] understanding only, and nevertheless can be given as objects of an intuition, though not of sensuous intuition (as coram intuitu intellectuali), such things would be called Noumena (intelligibilia).

One might feel inclined to think that the concept of Phenomena, as limited by the transcendental æsthetic, suggested by itself the objective reality of the Noumena, and justified a division of objects into phenomena and noumena, and consequently of the world into a sensible and intelligible world (mundus sensibilis et intelligibilis); and this in such a way that the distinction between the two should not refer to the logical form only of a more or less clear knowledge of one and the same object, but to a difference in their original presentation to our knowledge, which makes them to differ in themselves from each other in kind. For if the senses only represent to us something as it appears, that something must by itself also be a thing, and an object of a non-sensuous intuition, i.e. of the understanding. That is, there must be a kind of knowledge in which there is no sensibility, and which alone possesses absolute objective reality, representing objects as they are, while through the empirical use of our understanding we know things only as they appear. Hence it would seem to follow that, beside the empirical [p. 250] use of the categories (limited by sensuous conditions), there was another one, pure and yet objectively valid, and that we could not say, as we have hitherto done, that our knowledge of the pure understanding contained nothing but principles for the exhibition of phenomena, which, even a priori, could not apply to anything but the formal possibility of experience. Here, in fact, quite a new field would seem to be open, a world, as it were, realised in thought (nay, according to some, even in intuition), which would be a more, and not a less, worthy object for the pure understanding.

All our representations are no doubt referred by the understanding to some sort of object, and as phenomena are nothing but representations, the understanding refers them to a something, as the object of our sensuous intuition, this something being however the transcendental object only. This means a something equal to x, of which we do not, nay, with the present constitution of our understanding, cannot know anything, but which1 can only serve, as a correlatum of the unity of apperception, for the unity of the manifold in sensuous intuition, by means of which the understanding unites the manifold into the concept of an object. This transcendental object cannot be separated from the sensuous data, because in that case nothing would remain by which it could be [p. 251] thought. It is not therefore an object of knowledge in itself, but only the representation of phenomena, under the concept of an object in general, which can be defined by the manifold of sensuous intuition.

For this very reason the categories do not represent a peculiar object, given to the understanding only, but serve only to define the transcendental object (the concept of something in general) by that which is given us through the senses, in order thus to know empirically phenomena under the concepts of objects.

What then is the cause why people, not satisfied with the substratum of sensibility, have added to the phenomena the noumena, which the understanding only is supposed to be able to realise? It is this, that sensibility and its sphere, that is the sphere of phenomena, is so limited by the understanding itself that it should not refer to things by themselves, but only to the mode in which things appear to us, in accordance with our own subjective qualification. This was the result of the whole transcendental æsthetic, and it really follows quite naturally from the concept of a phenomenon in general, that something must correspond to it, which in itself is not a phenomenon, because a phenomenon cannot be anything by itself, apart from our mode of representation. [p. 252] Unless therefore we are to move in a constant circle, we must admit that the very word phenomenon indicates a relation to something the immediate representation of which is no doubt sensuous, but which nevertheless, even without this qualification of our sensibility (on which the form of our intuition is founded) must be something by itself, that is an object independent of our sensibility.

Hence arises the concept of a noumenon, which however is not positive, nor a definite knowledge of anything, but which implies only the thinking of something, without taking any account of the form of sensuous intuition. But in order that a noumenon may signify a real object that can be distinguished from all phenomena, it is not enough that I should free my thought of all conditions of sensuous intuition, but I must besides have some reason for admitting another kind of intuition besides the sensuous, in which such an object can be given; otherwise my thought would be empty, however free it may be from contradictions. It is true that we were not able to prove that the sensuous is the only possible intuition, though it is so for us: but neither could we prove that another kind of intuition was possible; and although our thought may take no account of any sensibility, the question always remains whether, after that, it is not a mere [p. 253] form of a concept, and whether any real object would thus be left.

The object to which I refer the phenomenon in general is the transcendental object, that is, the entirely indefinite thought of something in general. This cannot be called the noumenon, for I know nothing of what it is by itself, and have no conception of it, except as the object of sensuous intuition in general, which is therefore the same for all phenomena. I cannot lay hold of it by any of the categories, for these are valid for empirical intuitions only, in order to bring them under the concept of an object in general. A pure use of the categories is no doubt possible, that is, not self-contradictory, but it has no kind of objective validity, because it refers to no intuition to which it is meant to impart the unity of an object. The categories remain for ever mere functions of thought by which no object can be given to me, but by which I can only think whatever may be given to me in intuition.]

If all thought (by means of categories) is taken away from empirical knowledge, no knowledge of any object remains, because nothing can be thought by mere intuition, and the mere fact that there is within me an affection of my sensibility, establishes in no way any relation of such a representation to any object. If, on the contrary, all intuition is taken away, there always remains [p. 254] the form of thought, that is, the mode of determining an object for the manifold of a possible intuition. In this sense the categories may be said to extend further than sensuous intuition, because they can think objects in general without any regard to the special mode of sensibility in which they may be given; but they do not thus prove a larger sphere of objects, because we cannot admit that such objects can be given, without admitting the possibility of some other but sensuous intuition, for which we have no right whatever.

I call a concept problematic, if it is not self-contradictory, and if, as limiting other concepts, it is connected with other kinds of knowledge, while its objective reality cannot be known in any way. Now the concept of a noumenon, that is of a thing which can never be thought as an object of the senses, but only as a thing by itself (by the pure understanding), is not self-contradictory, because we cannot maintain that sensibility is the only form of intuition. That concept is also necessary, to prevent sensuous intuition from extending to things by themselves; that is, in order to limit the objective validity of sensuous knowledge (for all the rest to which sensuous intuition does not extend is called noumenon, for [p. 255] the very purpose of showing that sensuous knowledge cannot extend its domain over everything that can be thought by the understanding). But, after all, we cannot understand the possibility of such noumena, and whatever lies beyond the sphere of phenomena is (to us) empty; that is, we have an understanding which problematically extends beyond that sphere, but no intuition, nay not even the conception of a possible intuition, by which, outside the field of sensibility, objects could be given to us, and our understanding could extend beyond that sensibility in its assertory use. The concept of a noumenon is therefore merely limitative, and intended to keep the claims of sensibility within proper bounds, therefore of negative use only. But it is not a mere arbitrary fiction, but closely connected with the limitation of sensibility, though incapable of adding anything positive to the sphere of the senses.

A real division of objects into phenomena and noumena, and of the world into a sensible and intelligible world (in a positive sense),1 is therefore quite inadmissible, although concepts may very well be divided into sensuous and intellectual. For no objects can be assigned to these intellectual concepts, nor can they be represented as objectively valid. If we drop the senses, how are we to make it [p. 256] conceivable that our categories (which would be the only remaining concepts for noumena) have any meaning at all, considering that, in order to refer them to any object, something more must be given than the mere unity of thought, namely, a possible intuition, to which the categories could be applied? With all this the concept of a noumenon, if taken as problematical only, remains not only admissible, but, as a concept to limit the sphere of sensibility, indispensable. In this case, however, it is not a particular intelligible object for our understanding, but an understanding to which it could belong is itself a problem, if we ask how it could know an object, not discursively by means of categories, but intuitively, and yet in a nonsensuous intuition, — a process of which we could not understand even the bare possibility. Our understanding thus acquires a kind of negative extension, that is, it does not become itself limited by sensibility, but, on the contrary, limits it, by calling things by themselves (not considered as phenomena) noumena. In doing this, it immediately proceeds to prescribe limits to itself, by admitting that it cannot know these noumena by means of the categories, but can only think of them under the name of something unknown.

In the writings of modern philosophers, however, I meet with a totally different use of the terms of mundus sensibilis and intelligibilis,1 totally different from the meaning assigned to these terms by the ancients. [p. 257] Here all difficulty seems to disappear. But the fact is, that there remains nothing but mere word-mongery. In accordance with this, some people have been pleased to call the whole of phenomena, so far as they are seen, the world of sense; but so far as their connection, according to general laws of the understanding, is taken into account, the world of the understanding. Theoretical astronomy, which only teaches the actual observation of the starry heavens, would represent the former; contemplative astronomy, on the contrary (taught according to the Copernican system, or, it may be, according to Newton’s laws of gravitation), the latter, namely, a purely intelligible world. But this twisting of words is a mere sophistical excuse, in order to avoid a troublesome question, by changing its meaning according to one’s own convenience. Understanding and reason may be applied to phenomena, but it is very questionable whether they can be applied at all to an object which is not a phenomenon, but a noumenon; and it is this, when the object is represented as purely intelligible, that is, as given to the understanding only, and not to the senses. The question therefore is whether, besides the empirical use of the understanding (even in the Newtonian view of the world), a transcendental use is possible, referring to the noumenon, as its object; and that question we have answered decidedly in the negative.

When we therefore say that the senses represent [p. 258] objects to us as they appear, and the understanding as they are, the latter is not to be taken in a transcendental, but in a purely empirical meaning, namely, as to how they, as objects of experience, must be represented, according to the regular connection of phenomena, and not according to what they may be, as objects of the pure understanding, apart from their relation to possible experience, and therefore to our senses. This will always remain unknown to us; nay, we shall never know whether such a transcendental and exceptional knowledge is possible at all, at least as comprehended under our ordinary categories. With us understanding and sensibility cannot determine objects, unless they are joined together. If we separate them, we have intuitions without concepts, or concepts without intuitions, in both cases representations which we cannot refer to any definite object.

If, after all these arguments, anybody should still hesitate to abandon the purely transcendental use of the categories, let him try an experiment with them for framing any synthetical proposition. An analytical proposition does not in the least advance the understanding, which, as in such a proposition it is only concerned with what is already thought in the concept, does not ask whether the concept in itself has any reference to objects, or expresses only the unity of thought in general [p. 259] (this completely ignoring the manner in which an object may be given). The understanding in fact is satisfied if it knows what it contained in the concept of an object; it is indifferent as to the object to which the concept may refer. But let him try the experiment with any synthetical and so-called transcendental proposition, as for instance, ‘Everything that exists, exists as a substance, or as a determination inherent in it,’ or ‘Everything contingent exists as an effect of some other thing, namely, its cause,’ etc. Now I ask, whence can the understanding take these synthetical propositions, as the concepts are to apply, not to some possible experience, but to things by themselves (noumena)? Where is that third term to be found which is always required for a synthetical proposition, in order thus to join concepts which have no logical (analytical) relation with each other? It will be impossible to prove such a proposition, nay even to justify the possibility of any such pure assertion, without appealing to the empirical use of the understanding, and thus renouncing entirely the so-called pure and nonsensuous judgment. There are no principles therefore according to which the concepts of pure and merely intelligible objects could ever be applied, because we cannot imagine any way in which they could be given, and the problematic thought, which leaves a place open to them, serves only, like empty space, to limit the sphere of empirical principles, without containing or indicating [p. 260] any other object of knowledge, lying beyond that sphere.

APPENDIX

Of the Amphiboly of Reflective Concepts, owing to the Confusion of the Empirical with the Transcendental Use of the Understanding

Reflection (reflexio) is not concerned with objects themselves, in order to obtain directly concepts of them, but is a state of the mind in which we set ourselves to discover the subjective conditions under which we may arrive at concepts. It is the consciousness of the relation of given representations to the various sources of our knowledge by which alone their mutual relation can be rightly determined. Before saying any more of our representations, the first question is, to which faculty of knowledge they may all belong; whether it is the understanding or the senses by which they are connected and compared. Many a judgment is accepted from mere habit, or made from inclination, and as no reflection precedes or even follows it critically, the judgment is supposed [p. 261] to have had its origin in the understanding. It is not all judgments that require an investigation, that is, a careful attention with regard to the grounds of their truth; for if they are immediately certain, as for instance, that between two points there can be only one straight line, no more immediately certain marks of their truth than that which they themselves convey could be discovered. But all judgments, nay, all comparisons, require reflection, that is, a discrimination of the respective faculty of knowledge to which any given concepts belong. The act by which I place in general the comparison of representations by the side of the faculty of knowledge to which that comparison belongs, and by which I determine whether these representations are compared with each other as belonging to the pure understanding or to sensuous intuition, I call transcendental reflection. The relation in which the two concepts may stand to each other in one state of the mind is that of identity and difference, of agreement and opposition, of the internal and external, and finally of the determinable and the determination (matter and form). The right determination of that relation depends on the question in which faculty of knowledge they subjectively belong to each other, whether in sensibility or in the understanding. For the proper distinction of the latter is of great importance with regard to the manner in which the former must be considered. [p. 262]

Before proceeding to form any objective judgments, we have to compare the concepts with regard to the identity (of many representations under one concept) as the foundation of general judgments, or with regard to their difference as the foundation of particular judgments, or with regard to their agreement and opposition serving as the foundations of affirmative and negative judgments, etc. For this reason it might seem that we ought to call these concepts concepts of comparison (conceptus comparationis). But as, when the contents of concepts and not their logical form must be considered, that is, whether the things themselves are identical or different, in agreement or in opposition, etc., all things may have a twofold relation to our faculty of knowledge, namely, either to sensibility or to the understanding, and as the manner in which they belong to one another depends on the place to which they belong, it follows that the transcendental reflection, that is the power of determining the relation of given representations to one or the other class of knowledge, can alone determine their mutual relation. Whether the things are identical or different, in agreement or opposition, etc., cannot be established at once by the concepts themselves by means of a mere comparison (comparatio), but first of all by a proper discrimination of that class of knowledge to which they belong, that is, by transcendental reflection. It might therefore be said, that logical reflection is a mere comparison, because it takes no account of the faculty of knowledge to which any given representations belong, and treats [p. 263] them, so far as they are all found in the mind, as homogeneous, while transcendental reflection (which refers to the objects themselves) supplies the possibility of an objective comparison of representations among themselves, and is therefore very different from the other, the faculty of knowledge to which they belong not being the same. This transcendental reflection is a duty from which no one can escape who wishes to form judgments a priori. We shall now take it in hand, and may hope thus to throw not a little light on the real business of the understanding.

I.

Identity and Difference

When an object is presented to us several times, but each time with the same internal determinations (qualitas et quantitas), it is, so long as it is considered as an object of the pure understanding, always one and the same, one thing, not many (numerica identitas). But if it is a phenomenon, a comparison of the concepts is of no consequence, and though everything may be identical with regard to the concepts, yet the difference of the places of this phenomenon at the same time is a sufficient ground for admitting the numerical difference of the object (of the senses). Thus, though there may be no internal difference whatever (either in quality or quantity) between two drops of water, yet the fact that they may be seen [p. 264] at the same time in different places is sufficient to establish their numerical difference. Leibniz took phenomena to be things by themselves, intelligibilia, that is, objects of the pure understanding (though, on account of the confused nature of their representations, he assigned to them the name of phenomena), and from that point of view his principle of their indiscernibility (principium identitas indiscernibilium) could not be contested. As, however, they are objects of sensibility, and the use of the understanding with regard to them is not pure, but only empirical, their plurality and numerical diversity are indicated by space itself, as the condition of external phenomena. For one part of space, though it may be perfectly similar and equal to another, is still outside it, and for this very reason a part of space different from the first which, added to it, makes a larger space: and this applies to all things which exist at the same time in different parts of space, however similar or equal they may be in other respects.

II.

Agreement and Opposition

When reality is represented by the pure understanding only (realitas noumenon), no opposition can be conceived between realities, that is, no such relation that, if connected in one subject, they should annihilate the effects one of the other, as for instance 3 - 3 = 0. The real in [p. 265] the phenomena, on the contrary (realitas phenomenon), may very well be in mutual opposition, and if connected in one subject, one may annihilate completely or in part the effect of the other, as in the case of two forces moving in the same straight line, either drawing or impelling a point in opposite directions, or in the case of pleasure, counterbalancing a certain amount of pain.

III.

The Internal and the External

In an object of the pure understanding that only is internal which has no relation whatever (as regards its existence) to anything different from itself. The inner relations, on the contrary, of a substantia phenomenon in space are nothing but relations, and the substance itself a complex of mere relations. We only know substances in space through the forces which are active in a certain space, by either drawing others near to it (attraction) or by preventing others from penetrating into it (repulsion and impenetrability). Other properties constituting the concept of a substance appearing in space, and which we call matter, are unknown to us. As an object of the pure understanding, on the contrary, every substance must have internal determinations and forces bearing on the internal reality. But what other internal accidents can I think except those which my own internal sense presents [p. 266] to me, namely, something which is either itself thought, or something analogous to it? Hence Leibniz represented all substances (as he conceived them as noumena), even the component parts of matter (after having in thought removed from them everything implying external relation, and therefore composition also), as simple subjects endowed with powers of representation, in one word, as monads.

IV.

Matter and Form

These are two concepts which are treated as the foundation of all other reflection, so inseparably are they connected with every act of the understanding. The former denotes the determinable in general, the latter its determination (both in a purely transcendental meaning, all differences in that which is given and the mode in which it is determined being left out of consideration). Logicians formerly called the universal, matter; the specific difference, form. In every judgment the given concepts may be called the logical matter (for a judgment); their relation, by means of the copula, the form of a judgment. In every being its component parts (essentialia) are the matter; the mode in which they are connected in it, the essential form. With respect to things in general, unlimited reality was regarded as the matter of all possibility, and the limitation thereof (negation) as that form by which one [p. 267] thing is distinguished from another, according to transcendental concepts. The understanding demands first that something should be given (at least in concept) in order to be able afterwards to determine it in a certain manner. In the concept of the pure understanding therefore, matter comes before form, and Leibniz in consequence first assumed things (monads), and within them an internal power of representation, in order afterwards to found thereon their external relation, and the community of their states, that is, of their representations. In this way space and time were possible only, the former through the relation of substances, the latter through the connection of their determinations among themselves, as causes and effects. And so it would be indeed, if the pure understanding could be applied immediately to objects, and if space and time were determinations of things by themselves. But if they are sensuous intuitions only, in which we determine all objects merely as phenomena, then it follows that the form of intuition (as a subjective quality of sensibility) comes before all matter (sensations), that space and time therefore come before all phenomena, and before all data of experience, and render in fact all experience possible. As an intellectual philosopher Leibniz could not endure that this form should come before things and determine their possibility: a criticism quite just when he assumed that we see things as they are (though in a confused representation). But as sensuous intuition is a peculiar [p. 268] subjective condition on which all perception a priori depends, and the form of which is original and independent, the form must be given by itself, and so far from matter (or the things themselves which appear) forming the true foundation (as we might think, if we judged according to mere concepts), the very possibility of matter presupposes a formal intuition (space and time) as given.

NOTE ON THE AMPHIBOLY OF REFLECTIVE CONCEPTS

I beg to be allowed to call the place which we assign to a concept, either in sensibility or in the pure understanding, its transcendental place. If so, then the determination of this position which belongs to every concept, according to the difference of its use, and the directions for determining according to rules that place for all concepts, would be called transcendental topic; a doctrine which would thoroughly protect us against the subreptitious claims of the pure understanding and the errors arising from it, by always distinguishing to what faculty of knowledge each concept truly belongs. Every concept, or every title to which many kinds of knowledge belong, may be called a logical place. Upon this is based the logical topic of Aristotle, of which orators and schoolmasters avail themselves in order to find under certain titles of thought [p. 269] what would best suit the matter they have in hand, and thus to be able, with a certain appearance of thoroughness, to argue and wrangle to any extent.

Transcendental topic, on the contrary, contains no more than the above-mentioned four titles of all comparison and distinction, which differ from the categories because they do not serve to represent the object according to what constitutes its concept (quantity, reality, etc.), but only the comparison of representations, in all its variety, which precedes the concept of things. This comparison, however, requires first a reflection, that is, a determination of the place to which the representations of things which are to be compared belong, namely, whether they are thought by the pure understanding or given as phenomena by sensibility.

Concepts may be logically compared without our asking any questions as to what place their objects belong, whether as noumena to the understanding, or to sensibility as phenomena. But if with these concepts we wish to proceed to the objects themselves, a transcendental reflection is necessary first of all, in order to determine whether they are meant to be objects for the pure understanding or for sensibility. Without this reflection our use of these concepts would be very uncertain, and [p. 270] synthetical propositions would spring up which critical reason cannot acknowledge, and which are simply founded on transcendental amphiboly, that is, on our confounding an object of the pure understanding with a phenomenon.

For want of such a transcendental topic, and deceived by the amphiboly of reflective concepts, the celebrated Leibniz erected an intellectual system of the world, or believed at least that he knew the internal nature of things by comparing all objects with the understanding only and with the abstract formal concepts of his thought. Our table of reflective concepts gives us the unexpected advantage of being able to exhibit clearly the distinctive features of his system in all its parts, and at the same time the leading principle of this peculiar view which rested on a simple misunderstanding. He compared all things with each other by means of concepts only, and naturally found no other differences but those by which the understanding distinguishes its pure concepts from each other. The conditions of sensuous intuition, which carry their own differences, are not considered by him as original and independent; for sensibility was with him a confused mode of representation only, and not a separate source of representations. According to him a phenomenon was the representation of a thing by itself, though different, in its logical form, from knowledge by means of the [p. 271] understanding, because the phenomenon, in the ordinary absence of analysis, brings a certain admixture of collateral representations into the concept of a thing which the understanding is able to separate. In one word, Leibniz intellectualised phenomena, just as Locke, according to his system of Noogony (if I may use such an expression), sensualised all concepts of the understanding, that is, represented them as nothing but empirical, though abstract, reflective concepts. Instead of regarding the understanding and sensibility as two totally distinct sources of representations, which however can supply objectively valid judgments of things only in conjunction with each other, each of these great men recognised but one of them, which in their opinion applied immediately to things by themselves, while the other did nothing but to produce either disorder or order in the representations of the former.

Leibniz accordingly compared the objects of the senses with each other as things in general and in the understanding only. He did this,

First, so far as they are judged by the understanding to be either identical or different. As he considers their concepts only and not their place in intuition, in which alone objects can be given, and takes no account of the transcendental place of these concepts (whether the object is to be counted among phenomena or among things by themselves), it could not happen otherwise than [p. 272] that he should extend his principle of indiscernibility, which is valid with regard to concepts of things in general only, to objects of the senses also (mundus phaenomenon), and imagine that he thus added no inconsiderable extension to our knowledge of nature. No doubt, if I know a drop of water as a thing by itself in all its internal determinations, I cannot allow that one is different from the other, when their whole concepts are identical. But if the drop of water is a phenomenon in space, it has its place not only in the understanding (among concepts), but in the sensuous external intuition (in space), and in this case the physical place is quite indifferent with regard to the inner determinations of things, so that a place B can receive a thing which is perfectly similar or identical with another in place A, quite as well as if it were totally different from it in its internal determinations. Difference of place by itself and without any further conditions renders the plurality and distinction of objects as phenomena not only possible, but also necessary. That so-called law of Leibniz therefore is no law of nature, but only an analytical rule, or a comparison of things by means of concepts only.

Thirdly. The Leibnizian monadology has really no other foundation than that Leibniz represented the difference of the internal and the external in relation to the understanding only. Substances must have something internal, which is free from all external relations, and therefore from composition also. The simple, therefore, or uncompounded, is the foundation of the internal of things by themselves. This internal in the state of substances cannot consist in space, form, contact, or motion (all these determinations being external relations), and we cannot therefore ascribe to substances any other internal state but that which belongs to our own internal sense, namely, the state of representations. This is the history of the monads, which were to form the elements of the whole universe, and the energy of which consists in representations only, so that properly they can be active within themselves only.

For this reason, his principle of a possible community of substances could only be a pre-established harmony, and not a physical influence. For, as everything [p. 275] is actively occupied internally only, that is, with its own representations, the state of representations in one substance could not be in active connection with that of another; but it became necessary to admit a third cause, exercising its influence on all substances, and making their states to correspond with each other, not indeed by occasional assistance rendered in each particular case (systema assistentiae), but through the unity of the idea of a cause valid for all, and in which all together must receive their existence and permanence, and therefore also their reciprocal correspondence according to universal laws.

Fourthly. Leibniz’s celebrated doctrine of space and time, in which he intellectualised these forms of sensibility, arose entirely from the same delusion of transcendental reflection. If by means of the pure understanding alone I want to represent the external relations of things, I can do this only by means of the concept of their reciprocal action; and if I want to connect one state with another state of the same thing, this is possible only in the order of cause and effect. Thus it happened that Leibniz conceived space as a certain order in the community of substances, and time as the dynamical sequence of their states. That which space and time seem to possess as proper to themselves and independent [p. 276] of things, he ascribed to the confusion of these concepts. which made us mistake what is a mere form of dynamical relations for a peculiar and independent intuition, antecedent to things themselves. Thus space and time became with him the intelligible form of the connection of things (substances and their states) by themselves, and things were intelligible substances (substantiae noumena). Nevertheless he tried to make these concepts valid for phenomena, because he would not concede to sensibility any independent kind of intuition, but ascribed all, even the empirical representation of objects, to the understanding, leaving to the senses nothing but the contemptible work of confusing and mutilating the representations of the understanding.

But, even if we could predicate anything synthetically by means of the pure understanding of things by themselves (which however is simply impossible), this could never be referred to phenomena, because these do not represent things by themselves. We should therefore in such a case have to compare our concepts in a transcendental reflection under the conditions of sensibility only, and thus space and time would never be determinations of things by themselves, but of phenomena. What things may be by themselves we know not, nor need [p. 277] we care to know, because, after all, a thing can never come before me otherwise than as a phenomenon.

The remaining reflective conceptions have to be treated in the same manner. Matter is substantia phenomenon. What may belong to it internally, I seek for in all parts of space occupied by it, and in all effects produced by it, all of which, however, can be phenomena of the external senses only. I have therefore nothing that is absolutely, but only what is relatively internal, and this consists itself of external relations. Nay, what according to the pure understanding should be the absolutely internal of matter is a mere phantom, for matter is never an object of the pure understanding, while the transcendental object which may be the ground of the phenomenon which we call matter, is a mere something of which we could not even understand what it is, though somebody should tell us. We cannot understand anything except what carries with it in intuition something corresponding to our words. If the complaint ‘that we do not understand the internal of things,’ means that we do not comprehend by means of the pure understanding what the things which appear to us may be of themselves, it seems totally unjust and unreasonable; for it means that without senses we should be able to know and therefore to see things, that is, that we should possess a faculty of knowledge totally different from the human, not only in degree, but in kind [p. 278] and in intuition, in fact, that we should not be men, but beings of whom we ourselves could not say whether they are even possible, much less what they would be like. Observation and analysis of phenomena enter into the internal of nature, and no one can say how far this may go in time. Those transcendental questions, however, which go beyond nature, would nevertheless remain unanswerable, even if the whole of nature were revealed to us, for it is not given to us to observe even our own mind with any intuition but that of our internal sense. In it lies the mystery of the origin of our sensibility. Its relation to an object, and the transcendental ground of that unity, are no doubt far too deeply hidden for us, who can know even ourselves by means of the internal sense only, that is, as phenomena, and we shall never be able to use the same imperfect instrument of investigation in order to find anything but again and again phenomena, the non-sensuous, and non-phenomenal cause of which we are seeking in vain.

What renders this criticism of the conclusions by means of the acts of mere reflection extremely useful is, that it shows clearly the nullity of all conclusions with regard to objects compared with each other in the understanding only, and that it confirms at the same time what [p. 279] we have so strongly insisted on, namely, that phenomena, though they cannot be comprehended as things by themselves among the objects of the pure understanding, are nevertheless the only objects in which our knowledge can possess objective reality, i.e. where intuition corresponds to concepts.

When we reflect logically only, we only compare in our understanding concepts among themselves, trying to find out whether both have exactly the same contents, whether they contradict themselves or not, whether something belongs to a concept, or is added to it, and which of the two may be given, while the other may be a mode only of thinking the given concept. But if I refer these concepts to an object in general (in a transcendental sense), without determining whether it be an object of sensuous or intellectual intuition, certain limitations appear at once, warning us not to go beyond the concept, and upsetting all empirical use of it, thus proving that a representation of an object, as of a thing in general, is not only insufficient, but, if without sensuous determination, and independent of empirical conditions, self-contradictory. It is necessary therefore either to take no account at all of the object (as we do in logic) or, if not, then to think it under the conditions of sensuous intuition, because the intelligible would require a quite peculiar intuition which we do not possess, and, without it, would be nothing to us, while on the other side phenomena also could never [p. 280] be things by themselves. For if I represent to myself things in general only, the difference of external relations cannot, it is true, constitute a difference of the things themselves, but rather presupposes it; and, if the concept of one thing does not differ at all internally from that of another, I only have one and the same thing placed in different relations. Furthermore, by adding a mere affirmation (reality) to another, the positive in it is indeed augmented, and nothing is taken away or removed, so that we see that the real in things can never be in contradiction with itself, etc.

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A certain misunderstanding of these reflective concepts has, as we showed, exercised so great an influence on the use of the understanding, as to mislead even one of the most acute philosophers to the adoption of a so-called system of intellectual knowledge, which undertakes to determine objects without the intervention of the senses. For this reason the exposition of the cause of the misunderstanding, which lies in the amphiboly of these concepts, as the origin of false principles, is of great utility in determining and securing the true limits of the understanding.

It is no doubt true, that what can be affirmed or denied of a concept in general, can also be affirmed or denied of any part of it (dictum de omni et nullo); but it [p. 281] would be wrong so to change this logical proposition as to make it say that whatever is not contained in a general concept, is not contained either in the particular concepts comprehended under it; for these are particular concepts for the very reason that they contain more than is conceived in the general concept. Nevertheless the whole intellectual system of Leibniz is built up on this fallacy, and with it falls necessarily to the ground, together with all equivocation in the use of the understanding, that had its origin in it.

Leibniz’s principle of discernibility is really based on the supposition that, if a certain distinction is not to be found in the general concept of a thing, it could not be met with either in the things themselves, and that therefore all things were perfectly the same (numero eadem), which are not distinguished from each other in their concept also, as to quality or quantity. And because in the mere concept of a thing, no account has been taken of many a necessary condition of its intuition, it has rashly been concluded that that which, in forming an abstraction, has been intentionally left out of account, did really not exist anywhere, and nothing has been allowed to a thing except what is contained in its concept. [p. 282]

If by purely intelligible objects we understand things which, without all schemata of sensibility, are thought by mere categories, such objects are simply impossible. It is our sensuous intuition by which objects are given to us that forms the condition of the objective application of all the concepts of our understanding, and without that intuition the categories have no relation whatever to any object. Nay, even if we admitted a kind of intuition different from the sensuous, our functions of thought would have no meaning with regard to it. If we only mean objects of a non-sensuous intuition, to which our categories do not apply, and of which we can have no knowledge whatever (either intuitional or conceptual), there is no reason why noumena, in this merely negative meaning, should not be admitted, because in this case we mean no more than this, that our intuition does not embrace all things, but objects of our senses only; that, consequently, its objective validity is limited, and space left for some other kind of intuition, and consequently for things as objects of it. But in that sense the concept of a noumenon is problematical, that is, the representation of a thing of which we can neither say that it is possible or that it is impossible, because we have no conception of any kind of intuition but that of our senses, or of any kind of concepts but of our categories, [p. 287] neither of them being applicable to any extra-sensuous object. We cannot therefore extend in a positive sense the field of the objects of our thought beyond the conditions of our sensibility, or admit, besides phenomena, objects of pure thought, that is, noumena, simply because they do not possess any positive meaning that could be pointed out. For it must be admitted that the categories by themselves are not sufficient for a knowledge of things, and that, without the data of sensibility, they would be nothing but subjective forms of unity of the understanding, and without an object. We do not say that thought is a mere product of the senses, and therefore limited by them, but it does not follow that therefore thought, without sensibility, has its own pure use, because it would really be without an object. Nor would it be right to call the noumenon such an object of the pure understanding, for the noumenon means the problematical concept of an object, intended for an intuition and understanding totally different from our own, and therefore themselves mere problems. The concept of the noumenon is not therefore the concept of an object, but only a problem, inseparable from the limitation of our sensibility, whether there may not be objects independent of its intuition. This is a question that [p. 288] can only be answered in an uncertain way, by saying that as sensuous intuition does not embrace all things without exception, there remains a place for other objects, that cannot therefore be absolutely denied, but cannot be asserted either as objects of our understanding, because there is no definite concept for them (our categories being unfit for that purpose).

The understanding therefore limits the sensibility without enlarging thereby its own field, and by warning the latter that it can never apply to things by themselves, but to phenomena only, it forms the thought of an object by itself, but as transcendental only, which is the cause of phenomena, and therefore never itself a phenomenon: which cannot be thought as quantity, nor as reality, nor as substance (because these concepts require sensuous forms in which to determine an object), and of which therefore it must always remain unknown, whether it is to be found within us only, or also without us; and whether, if sensibility were removed, it would vanish or remain. If we like to call this object noumenon, because the representation of it is not sensuous, we are at liberty to do so. But as we cannot apply to it any of the concepts of our understanding, such a representation remains to us empty, serving no purpose but that of indicating the limits of our sensuous knowledge, and leaving at the same time an [p. 289] empty space which we cannot fill either by possible experience, or by the pure understanding.

The critique of the pure understanding does not therefore allow us to create a new sphere of objects beyond those which can come before it as phenomena, or to stray into intelligible worlds, or even into the concept of such. The mistake which leads to this in the most plausible manner, and which, though excusable, can never be justified, consists in making the use of the understanding, contrary to its very intention, transcendental, so that objects, that is, possible intuitions, are made to conform to concepts, not concepts to possible intuitions, on which alone their objective validity can rest. The cause of this is again, that apperception, and with it thought, precedes every possible determinate arrangement of representations. We are thinking something in general, and determine it on one side sensuously, but distinguish at the same time the general object, represented in abstraction, from this particular mode of sensuous intuition. Thus there remains to us a mode of determining the object by thought only, which, though it is a mere logical form without any contents, seems to us nevertheless a mode in which the object by itself exists (noumenon), without regard to the intuition which is restricted to our senses. [p. 290]

*     *     *     *     *     *     *     *

Before leaving this transcendental Analytic, we have to add something which, though in itself of no particular importance, may yet seem to be requisite for the completeness of the system. The highest concept of which all transcendental philosophy generally begins, is the division into the possible and the impossible. But, as all division presupposes a divisible concept, a higher concept is required, and this is the concept of an object in general, taken as problematical, it being left uncertain whether it be something or nothing. As the categories are the only concepts which apply to objects in general, the distinction whether an object is something or nothing must proceed according to the order and direction of the categories.

I. Opposed to the concepts of all, many, and one, is the concept which annihilates everything, that is, none; and thus the object of a concept, to which no intuition can be found to correspond, is = 0, that is, a concept without an object, like the noumena, which cannot be counted as possibilities, though not as impossibilities either (ens nationis); or like certain fundamental forces, [p. 291] which have been newly invented, and have been conceived without contradiction, but at the same time without any example from experience, and must not therefore be counted among possibilities.

II. Reality is something, negation is nothing; that is, it is the concept of the absence of an object, as shadow or cold (nihil privativum).

III. The mere form of intuition (without substance) is in itself no object, but the merely formal condition of it (as a phenomenon), as pure space and pure time (ens imaginarium), which, though they are something, as forms of intuition, are not themselves objects of intuition.

IV. The object of a concept which contradicts itself, is nothing, because the concept is nothing; it is simply the impossible, as a figure composed of two straight lines (nihil negativum).

A table showing this division of the concept of nothing (the corresponding division of the concept of something follows by itself) would have to be arranged as follows.

We see that the ens rationis (No. 1) differs from the ens negativum (No. 4), because the former cannot be counted among the possibilities, being the result of fancy, though not self-contradictory, while the latter is opposed to possibility, the concept annihilating itself. Both, however, are empty concepts. The nihil privativum (No. 2) and the ens imaginarium (No. 3) are, on the contrary, empty data for concepts. It would be impossible to represent to ourselves darkness, unless light had been given to the senses, or space, unless extended beings had been perceived. The negation, as well as the pure form of intuition are, without something real, no objects.

Division II

Transcendental Dialectic in two books, with their chapters and sections [p. 293]

INTRODUCTION

1.

Of Transcendental Appearance (Illusion)

We call Dialectic in general a logic of illusion (eine Logik des Scheins). This does not mean that it is a doctrine of probability (Wahrscheinlichkeit), for probability is a kind of truth, known through insufficient causes, the knowledge of which is therefore deficient, but not deceitful, and cannot properly be separated from the analytical part of logic. Still less can phenomenon (Erscheinung) and illusion (Schein) be taken as identical. For truth or illusion is not to be found in the objects of intuition, but in the judgments upon them, so far as they are thought. It is therefore quite right to say, that the senses never err, not because they always judge rightly, but because they do not judge at all. Truth therefore and error, and consequently illusory appearance also, as the cause of error, exist in our judgments only, that is, in the relation of an object to our understanding. No error exists in our knowledge, if it completely agrees with the laws of our understanding, nor can there be [p. 294] an error in a representation of the senses, because they involve no judgment, and no power of nature can, of its own accord, deviate from its own laws. Therefore neither the understanding by itself (without the influence of another cause), nor the senses by themselves could ever err. The understanding could not err, because as long as it acts according to its own laws, the effect (the judgment) must necessarily agree with those laws, and the formal test of all truth consists in this agreement with the laws of the understanding. The senses cannot err, because there is in them no judgment at all, whether true or false. Now as we have no other sources of knowledge but these two, it follows that error can only arise through the unperceived influence of the sensibility on the understanding, whereby it happens that subjective grounds of judgment are mixed up with the objective, and cause them to deviate from their destination;1 just as a body in motion would, if left to itself, always follow a straight line in the same direction, which is changed however into a curvilinear motion, as soon as another force influences it at the same time in a different direction. In order to distinguish the proper action [p. 295] of the understanding from that other force which is mixed up with it, it will be necessary to look on an erroneous judgment as the diagonal between two forces, which determine the judgment in two different directions, forming as it were an angle, and to dissolve that composite effect into the simple ones of the understanding and of the sensibility, which must be effected in pure judgments a priori by transcendental reflection, whereby, as we tried to show, the right place is assigned to each representation in the faculty of knowledge corresponding to it, and the influence of either faculty upon such representation is determined.

It is not at present our business to treat of empirical, for instance, optical appearance or illusion, which occurs in the empirical use of the otherwise correct rules of the understanding, and by which, owing to the influence of imagination, the faculty of judgment is misled. We have to deal here with nothing but the transcendental illusion, which touches principles never even intended to be applied to experience, which might give us a test of their correctness, — an illusion which, in spite of all the warnings of criticism, tempts us far beyond the empirical use of the categories, and deludes us with the mere dream of an extension of the pure understanding. All principles the application of which is entirely confined within the limits of possible experience, we [p. 296] shall call immanent; those, on the contrary, which tend to transgress those limits, transcendent. I do not mean by this the transcendental use or abuse of the categories, which is a mere fault of the faculty of the judgment, not being as yet sufficiently subdued by criticism nor sufficiently attentive to the limits of the sphere within which alone the pure understanding has full play, but real principles which call upon us to break down all those barriers, and to claim a perfectly new territory, which nowhere recognises any demarcation at all. Here transcendental and transcendent do not mean the same thing. The principles of the pure understanding, which we explained before, are meant to be only of empirical, and not of transcendental application, that is, they cannot transcend the limits of experience. A principle, on the contrary, which removes these landmarks, nay, insists on our transcending them, is called transcendent. If our critique succeeds in laying bare the illusion of those pretended principles, the other principles of a purely empirical use may, in opposition to the former, be called immanent.

Logical illusion, which consists in a mere imitation of the forms of reason (the illusion of sophistic syllogisms), arises entirely from want of attention to logical rules. It disappears at once, when our attention [p. 297] is roused. Transcendental illusion, on the contrary, does not disappear, although it has been shown up, and its worthlessness rendered clear by means of transcendental criticism, as, for instance, the illusion inherent in the proposition that the world must have a beginning in time. The cause of this is that there exists in our reason (considered subjectively as a faculty of human knowledge) principles and maxims of its use, which have the appearance of objective principles, and lead us to mistake the subjective necessity of a certain connection of our concepts in favour of the understanding for an objective necessity in the determination of things by themselves. This illusion is as impossible to avoid as it is to prevent the sea from appearing to us higher at a distance than on the shore, because we see it by higher rays of light; or to prevent the moon from appearing, even to an astronomer, larger at its rising, although he is not deceived by that illusion.

Transcendental Dialectic must, therefore, be content to lay bare the illusion of transcendental judgments and guarding against its deceptions — but it will never succeed in removing the transcendental illusion (like the logical), and putting an end to it altogether. [p. 298] For we have here to deal with a natural and inevitable illusion, which itself rests on subjective principles, representing them to us as objective, while logical Dialectic, in removing sophisms, has to deal merely with a mistake in applying the principles, or with an artificial illusion produced by an imitation of them. There exists, therefore, a natural and inevitable Dialectic of pure reason, not one in which a mere bungler might get entangled from want of knowledge, or which a sophist might artificially devise to confuse rational people, but one that is inherent in, and inseparable from human reason, and which, even after its illusion has been exposed, will never cease to fascinate our reason, and to precipitate it into momentary errors, such as require to be removed again and again.

2.

Of Pure Reason, as the Seat of Transcendental Illusion

A.

Of Reason in General

All our knowledge begins with the senses, proceeds thence to the understanding, and ends with reason. There is nothing higher than reason, for working up the material of intuition, and comprehending it under the highest unity of thought. As it here becomes [p. 299] necessary to give a definition of that highest faculty of knowledge, I begin to feel considerable misgivings. There is of reason, as there is of the understanding, a purely formal, that is logical use, in which no account is taken of the contents of knowledge; but there is also a real use, in so far as reason itself contains the origin of certain concepts and principles, which it has not borrowed either from the senses or from the understanding. The former faculty has been long defined by logicians as the faculty of mediate conclusions, in contradistinction to immediate ones (consequentiae immediatae); but this does not help us to understand the latter, which itself produces concepts. As this brings us face to face with the division of reason into a logical and a transcendental faculty, we must look for a higher concept for this source of knowledge, to comprehend both concepts: though, according to the analogy of the concepts of the understanding, we may expect that the logical concept will give us the key to the transcendental, and that the table of the functions of the former will give us the genealogical outline of the concepts of reason.

In the first part of our transcendental logic we defined the understanding as the faculty of rules, and we now distinguish reason from it, by calling it the faculty of principles. [p. 300]

The term principle is ambiguous, and signifies commonly some kind of knowledge only that may be used as a principle, though in itself, and according to its origin, it is no principle at all. Every general proposition, even though it may have been derived from experience (by induction), may serve as a major in a syllogism of reason; but it is not on that account a principle. Mathematical axioms, as, for instance, that between two points there can be only one straight line, constitute even general knowledge a priori, and may therefore, with reference to the cases which can be brought under them, rightly be called principles. Nevertheless it would be wrong to say, that this property of a straight line, in general and by itself, is known to us from principles, for it is known from pure intuition only.

I shall therefore call it knowledge from principles, whenever we know the particular in the general, by means of concepts. Thus every syllogism of reason is a form of deducing some kind of knowledge from a principle, because the major always contains a concept which enables us to know, according to a principle, everything that can be comprehended under the conditions of that concept. As every general knowledge may serve as a major in such a syllogism, and as the understanding supplies such general propositions a priori, these no doubt may, with reference to their possible use, be called principles. [p. 301]

But, if we consider these principles of the pure understanding in themselves, and according to their origin, we find that they are anything rather than knowledge from concepts. They would not even be possible a priori, unless we relied on pure intuition (in mathematics) or on conditions of a possible experience in general. That everything which happens has a cause, can by no means be concluded from the concept of that which happens; on the contrary, that very principle shows in what manner alone we can form a definite empirical concept of that which happens.

It is impossible therefore for the understanding to supply us with synthetical knowledge from concepts, and it is really that kind of knowledge which I call principles absolutely; while all general propositions may be called principles relatively.

It is an old desideratum, which at some time, however distant, may be realised, that, instead of the endless variety of civil laws, their principles might be discovered, for thus alone the secret might be found of what is called simplifying legislation. Such laws, however, are only limitations of our freedom under conditions by which it always agrees with itself; they refer to something which is entirely our own work, and of which we ourselves can be the cause, by means of these concepts. But that objects in themselves, as for instance material nature, should be subject to principles, and be determined according [p. 302] to mere concepts, is something, if not impossible, at all events extremely contradictory. But be that as it may (for on this point we have still all investigations before us), so much at least is clear, that knowledge from principles (by itself) is something totally different from mere knowledge of the understanding, which, in the form of a principle, may no doubt precede other knowledge, but which by itself (in so far as it is synthetical) is not based on mere thought, nor contains anything general, according to concepts.

If the understanding is a faculty for producing unity among phenomena, according to rules, reason is the faculty for producing unity among the rules of the understanding, according to principles. Reason therefore never looks directly to experience, or to any object, but to the understanding, in order to impart a priori through concepts to its manifold kinds of knowledge a unity that may be called the unity of reason, and is very different from the unity which can be produced by the understanding.

This is a general definition of the faculty of reason, so far as it was possible to make it intelligible without the help of illustrations, which are to be given hereafter.

B.

Of the Logical Use of Reason [p. 303]

A distinction is commonly made between what is immediately known and what is only inferred. That in a figure bounded by three straight lines there are three angles, is known immediately, but that these angles together are equal to two right angles, is only inferred. As we are constantly obliged to infer, we grow so accustomed to it, that in the end we no longer perceive this difference, and as in the case of the so-called deceptions of the senses, often mistake what we have only inferred for something perceived immediately. In every syllogism there is first a fundamental proposition; secondly, another deduced from it; and lastly, the conclusion (consequence), according to which the truth of the latter is indissolubly connected with the truth of the former. If the judgment or the conclusion is so clearly contained in the first that it can be inferred from it without the mediation or intervention of a third representation, the conclusion is called immediate (consequentia immediata): though I should prefer to call it a conclusion of the understanding. But if, besides the fundamental knowledge, another judgment is required to bring out the consequence, then the conclusion is called a conclusion of reason. In the proposition ‘all men are mortal,’ the following propositions are contained: some men are mortal; or some mortals are men; or nothing that is immortal is a man. These are therefore immediate [p. 304] inferences from the first. The proposition, on the contrary, all the learned are mortal, is not contained in the fundamental judgment, because the concept of learned does not occur in it, and can only be deduced from it by means of an intervening judgment.

In every syllogism I first think a rule (the major) by means of the understanding. I then bring some special knowledge under the condition of the rule (the minor) by means of the faculty of judgment, and I finally determine my knowledge through the predicate of the rule (conclusio), that is, a priori, by means of reason. It is therefore the relation represented by the major proposition, as the rule, between knowledge and its condition, that constitutes the different kinds of syllogism. Syllogisms are therefore threefold, like all judgments, differing from each other in the manner in which they express the relation of knowledge in the understanding, namely, categorical, hypothetical, and disjunctive.

If, as often happens, the conclusion is put forward as a judgment, in order to see whether it does not follow from other judgments by which a perfectly different object is conceived, I try to find in the understanding the assertion of that conclusion, in order to see whether it does not exist in it, under certain conditions, according to a general rule. If I find such a condition, and if the object of the conclusion can be brought under the given [p. 305] condition, then that conclusion follows from the rule which is valid for other objects of knowledge also. Thus we see that reason, in forming conclusions, tries to reduce the great variety of the knowledge of the understanding to the smallest number of principles (general conditions), and thereby to produce in it the highest unity.

C.

Of the Pure Use of Reason

The question to which we have at present to give an answer, though a preliminary one only, is this, whether reason can be isolated and thus constitute by itself an independent source of concepts and judgments, which spring from it alone, and through which it has reference to objects, or whether it is only a subordinate faculty for imparting a certain form to any given knowledge, namely, a logical form, a faculty whereby the cognitions of the understanding are arranged among themselves only, and lower rules placed under higher ones (the condition of the latter comprehending in its sphere the condition of the former) so far as all this can be done by their comparison. Variety of rules with unity of principles is a requirement of reason for the purpose of bringing the understanding into perfect agreement with itself, just as the understanding brings the variety of intuition under concepts, and thus imparts to intuition a connected form. Such a principle however prescribes no law to the objects [p. 306] themselves, nor does it contain the ground on which the possibility of knowing and determining objects depends. It is merely a subjective law of economy, applied to the stores of our understanding; having for its purpose, by means of a comparison of concepts, to reduce the general use of them to the smallest possible number, but without giving us a right to demand of the objects themselves such a uniformity as might conduce to the comfort and the extension of our understanding, or to ascribe to that maxim any objective validity. In one word, the question is, whether reason in itself, that is pure reason, contains synthetical principles and rules a priori, and what those principles are?

The merely formal and logical procedure of reason in syllogisms gives us sufficient hints as to the ground on which the transcendental principle of synthetical knowledge, by means of pure reason, is likely to rest.

First, a syllogism, as a function of reason, does not refer to intuitions in order to bring them under rules (as the understanding does with its categories), but to concepts and judgments. Although pure reason refers in the end to objects, it has no immediate relation to them and their intuition, but only to the understanding and its judgments, these having a direct relation to the [p. 307] senses and their intuition, and determining their objects. Unity of reason is therefore never the unity of a possible experience, but essentially different from it, as the unity of the understanding. That everything which happens has a cause, is not a principle discovered or prescribed by reason, it only makes the unity of experience possible, and borrows nothing from reason, which without this relation to possible experience could never, from mere concepts, have prescribed such a synthetical unity.

Secondly. Reason, in its logical employment, looks for the general condition of its judgment (the conclusion), and the syllogism produced by reason is itself nothing but a judgment by means of bringing its condition under a general rule (the major). But as this rule is again liable to the same experiment, reason having to seek, as long as possible, the condition of a condition (by means of a prosyllogism), it is easy to see that it is the peculiar principle of reason (in its logical use) to find for every conditioned knowledge of the understanding the unconditioned, whereby the unity of that knowledge may be completed.

This logical maxim, however, cannot become a principle of pure reason, unless we admit that, whenever the condition is given, the whole series of conditions, subordinated to one another, a series, which consequently is [p. 308] itself unconditioned, is likewise given (that is, is contained in the object and its connection).

Such a principle of pure reason, however, is evidently synthetical; for analytically the conditioned refers no doubt to some condition, but not to the unconditioned. From this principle several other synthetical propositions also must arise of which the pure understanding knows nothing; because it has to deal with objects of a possible experience only, the knowledge and synthesis of which are always conditioned. The unconditioned, if it is really to be admitted, has to be especially considered with regard to all the determinations which distinguish it from whatever is conditioned, and will thus supply material for many a synthetical proposition a priori.

The principles resulting from this highest principle of pure reason will however be transcendent, with regard to all phenomena; that is to say, it will be impossible ever to make any adequate empirical use of such a principle. It will thus be completely different from all principles of the understanding, the use of which is entirely immanent and directed to the possibility of experience only. The task that is now before us in the transcendental Dialectic which has to be developed from sources deeply hidden in the human reason, is this: to discover the correctness or otherwise the falsehood of the principle that the series of conditions (in the synthesis of phenomena, or of objective thought in general) extends to the unconditioned, and what consequences result therefrom with regard to the empirical use of the understanding: — to find [p. 309] out whether there is really such an objectively valid principle of reason, and not only, in place of it, a logical rule which requires us, by ascending to ever higher conditions, to approach their completeness, and thus to bring the highest unity of reason, which is possible to us, into our knowledge: to find out, I say, whether, by some misconception, a mere tendency of reason has not been mistaken for a transcendental principle of pure reason, postulating, without sufficient reflection, absolute completeness in the series of conditions in the objects themselves, and what kind of misconceptions and illusions may in that case have crept into the syllogisms of reason, the major proposition of which has been taken over from pure reason (being perhaps a petitio rather than a postulatum), and which ascend from experience to its conditions. We shall divide it into two parts, of which the first will treat of the transcendent concepts of pure reason, the second of transcendent and dialectical syllogisms.

[1 ]Additions of the Second Edition.

[1 ]I am treating here of the real definition, which not only puts in place of the name of a thing other and more intelligible words, but that which contains a clear mark by which the object (definitum) can at all times be safely recognised, and by which the defined concept becomes fit for practical use. A real definition (Realarklärung) must therefore render clear the concept itself, and its objective reality also. Of this kind are the mathematical explanations which represent an object in intuition, according to its concept.

[2 ]Read nimmt instead of nehmen, and können instead of könne.

[1 ]The passage from ‘It seems to be’ to ‘objective concepts’ is left out in the Second Edition, and replaced by a short note, see Supplement XXIII.

[1 ]The passage from ‘Appearances’ to ‘given to me in intuition’ is left out in the Second Edition, and replaced by Supplement XXIV.

[1 ]Read welches instead of welcher.

[1 ]Addition of the Second Edition.

[1 ]An additional note in the Second Edition is given in Supplement XXV.

[1 ]Sensibility, if subjected to the understanding as the object on which it exercises its function, is the source of real knowledge, but sensibility, if it influences the action of the understanding itself and leads it on to a judgment, is the cause of error.