Front Page Titles (by Subject) Section I: Of the Principles of a Transcendental Deduction in General - Critique of Pure Reason
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Section I: Of the Principles of a Transcendental Deduction in General - Friedrich Max Müller, Critique of Pure Reason 
Immanuel Kant’s Critique of Pure Reason. In Commemoration of the Centenary of its First Publication. Translated into English by F. Max Mueller (2nd revised ed.) (New York: Macmillan, 1922).
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Of the Principles of a Transcendental Deduction in General
Jurists, when speaking of rights and claims, distinguish in every lawsuit the question of right (quid juris) from the question of fact (quid facti), and in demanding proof of both they call the former, which is to show the right or, it may be, the claim, the deduction. We, not being jurists, make use of a number of empirical concepts, without opposition from anybody, and consider ourselves justified, without any deduction, in attaching to them a sense or imaginary meaning, because we can always appeal to experience to prove their objective reality. There exist however illegitimate concepts also, such as, for instance, chance, or fate, which through an almost general indulgence are allowed to be current, but are yet from time to time challenged by the question quid juris. In that case we are greatly embarrassed in looking for their deduction, there being no clear legal title, whether from experience or from reason, on which their [p. 85] claim to employment could be clearly established.
Among the many concepts, however, which enter into the complicated code of human knowledge, there are some which are destined for pure use a priori, independent of all experience, and such a claim requires at all times a deduction,1 because proofs from experience would not be sufficient to establish the legitimacy of such a use, though it is necessary to know how much concepts can refer to objects which they do not find in experience. I call the explanation of the manner how such concepts can a priori refer to objects their transcendental deduction, and distinguish it from the empirical deduction which shows the manner how a concept may be gained by experience and by reflection on experience; this does not touch the legitimacy, but only the fact whence the possession of the concept arose.
We have already become acquainted with two totally distinct classes of concepts, which nevertheless agree in this, that they both refer a priori to objects, namely, the concepts of space and time as forms of sensibility, and the categories as concepts of the understanding. It would be labour lost to attempt an empirical deduction of them, because their distinguishing characteristic is that they refer to objects without having borrowed anything from experience for their representation. [p. 86] If therefore a deduction of them is necessary, it can only be transcendental.
It is possible, however, with regard to these concepts, as with regard to all knowledge, to try to discover in experience, if not the principle of their possibility, yet the contingent causes of their production. And here we see that the impressions of the senses give the first impulse to the whole faculty of knowledge with respect to them, and thus produce experience which consists of two very heterogeneous elements, namely, matter for knowledge, derived from the senses, and a certain form according to which it is arranged, derived from the internal source of pure intuition and pure thought, first brought into action by the former, and then producing concepts. Such an investigation of the first efforts of our faculty of knowledge, beginning with single perceptions and rising to general concepts, is no doubt very useful, and we have to thank the famous Locke for having been the first to open the way to it. A deduction of the pure concepts a priori, however, is quite impossible in that way. It lies in a different direction, because, with reference to their future use, which is to be entirely independent of experience, a very different certificate of birth will be required from that of mere descent from experience. We may call this attempted physiological derivation (which cannot properly be called deduction, [p. 87] because it refers to a quaestio facti), the explanation of the possession of pure knowledge. It is clear therefore that of these pure concepts a priori a transcendental deduction only is possible, and that to attempt an empirical deduction of them is mere waste of time, which no one would think of except those who have never understood the very peculiar nature of that kind of knowledge.
But though it may be admitted that the only possible deduction of pure knowledge a priori must be transcendental, it has not yet been proved that such a deduction is absolutely necessary. We have before, by means of a transcendental deduction, followed up the concepts of space and time to their very sources, and explained and defined their objective validity a priori. Geometry, however, moves along with a steady step, through every kind of knowledge a priori, without having to ask for a certificate from philosophy as to the pure legitimate descent of its fundamental concept of space. But it should be remarked that in geometry this concept is used with reference to the outer world of sense only, of which space is the pure form of intuition, and where geometrical knowledge, being based on a priori intuition, possesses immediate evidence, the objects being given, so far as their form is concerned, through their very knowledge a priori in intuition. When we come, however, [p. 88] to the pure concepts of the understanding, it becomes absolutely necessary to look for a transcendental deduction, not only for them, but for space also, because they, not being founded on experience, apply to objects generally, without any of the conditions of sensibility; and, speaking of objects, not through predicates of intuition and sensibility, but of pure thought a priori, are not able to produce in intuition a priori any object on which, previous to all experience, their synthesis was founded. These concepts of pure understanding, therefore, not only excite suspicion with regard to the objective validity and the limits of their own application, but render even the concept of space equivocal, because of an inclination to apply it beyond the conditions of sensuous intuition, which was the very reason that made a transcendental deduction of it, such as we gave before, necessary. Before the reader has made a single step in the field of pure reason, he must be convinced of the inevitable necessity of such a transcendental deduction, otherwise he would walk on blindly and, after having strayed in every direction, he would only return to the same ignorance from which he started. He must at the same time perceive the inevitable difficulty of such a deduction, so that he may not complain about obscurity where the object itself is obscure, or weary too soon with our removal of obstacles, the fact being that we have [p. 89] either to surrender altogether all claims to the knowledge of pure reason — the most favourite field of all philosophers, because extending beyond the limits of all possible experience — or to bring this critical investigation to perfection.
It was easy to show before, when treating of the concepts of space and time, how these, though being knowledge a priori, refer necessarily to objects, and how they make a synthetical knowledge of them possible, which is independent of all experience. For, as no object can appear to us, that is, become an object of empirical intuition, except through such pure forms of sensibility, space and time are pure intuitions which contain a priori the conditions of the possibility of objects as phenomena, and the synthesis in these intuitions possesses objective validity.
The categories of the understanding, on the contrary, are not conditions under which objects can be given in intuition, and it is quite possible therefore that objects should appear to us without any necessary reference to the functions of the understanding, thus showing that the understanding contains by no means any of their conditions a priori. There arises therefore here a difficulty, which we did not meet with in the field of sensibility, namely, how subjective conditions of thought can have objective validity, that is, become conditions of the possibility of the knowledge of objects. It cannot be [p. 90] denied that phenomena may be given in intuition without the functions of the understanding. For if we take, for instance, the concept of cause, which implies a peculiar kind of synthesis, consisting in placing according to a rule after something called A something totally different from it, B, we cannot say that it is a priori clear why phenomena should contain something of this kind. We cannot appeal for it to experience, because what has to be proved is the objective validity of this concept a priori. It would remain therefore a priori doubtful whether such a concept be not altogether empty, and without any corresponding object among phenomena. It is different with objects of sensuous intuition. They must conform to the formal conditions of sensibility existing a priori in the mind, because otherwise they could in no way be objects to us. But why besides this they should conform to the conditions which the understanding requires for the synthetical unity of thought, does not seem to follow quite so easily. For we could quite well imagine that phenomena might possibly be such that the understanding should not find them conforming to the conditions of its synthetical unity, and all might be in such confusion that nothing should appear in the succession of phenomena which could supply a rule of synthesis, and correspond, for instance, to the concept of cause and effect, so that this concept would thus be quite empty, null, and meaningless. With all this phenomena would offer objects to our intuition, because intuition by itself does not require the functions [p. 91] of thought.
It might be imagined that we could escape from the trouble of these investigations by saying that experience offers continually examples of such regularity of phenomena as to induce us to abstract from it the concept of cause, and it might be attempted to prove thereby the objective validity of such a concept. But it ought to be seen that in this way the concept of cause cannot possibly arise, and that such a concept ought either to be founded a priori in the understanding or be surrendered altogether as a mere hallucination. For this concept requires strictly that something, A, should be of such a nature that something else, B, follows from it necessarily and according to an absolutely universal rule. Phenomena no doubt supply us with cases from which a rule becomes possible according to which something happens usually, but never so that the result should be necessary. There is a dignity in the synthesis of cause and effect which cannot be expressed empirically, for it implies that the effect is not only an accessory to the cause, but given by it and springing from it. Nor is the absolute universality of the rule a quality inherent in empirical rules, which by means of induction cannot receive any but a relative universality, that [p. 92] is, a more or less extended applicability. If we were to treat the pure concepts of the understanding as merely empirical products, we should completely change their character and their use.
Transition to a Transcendental Deduction of the Categories
Two ways only are possible in which synthetical representations and their objects can agree, can refer to each other with necessity, and so to say meet each other. Either it is the object alone that makes the representation possible, or it is the representation alone that makes the object possible. In the former case their relation is empirical only, and the representation therefore never possible a priori. This applies to phenomena with reference to whatever in them belongs to sensation. In the latter case, though representation by itself (for we do not speak here of its1 causality by means of the will) cannot produce its object so far as its existence is concerned, nevertheless the representation determines the object a priori, if through it alone it is possible to know anything as an object. To know a thing as an object is possible only under two conditions. First, there must be intuition by which the object is given us, though as a phenomenon only, secondly, there must be a concept by which [p. 93] an object is thought as corresponding to that intution. From what we have said before it is clear that the first condition, namely, that under which alone objects can be seen, exists, so far as the form of intuition is concerned, in the soul a priori. All phenomena therefore must conform to that formal condition of sensibility, because it is through it alone that they appear, that is, that they are given and empirically seen.
Now the question arises whether there are not also antecedent concepts. a priori, forming conditions under which alone something can be, if not seen, yet thought as an object in general; for in that case all empirical knowledge of objects would necessarily conform to such concepts, it being impossible that anything should become an object of experience without them. All experience contains, besides the intuition of the senses by which something is given, a concept also of the object, which is given in intuition as a phenomenon. Such concepts of objects in general therefore must form conditions a priori of all knowledge produced by experience, and the objective validity of the categories, as being such concepts a priori, rests on this very fact that by them alone, so far as the form of thought is concerned, experience becomes possible. If by them only it is possible to think any object of experience, it follows that they refer by necessity and a priori to all objects of experience.
There is therefore a principle for the transcendental [p. 94] deduction of all concepts a priori which must guide the whole of our investigation, namely, that all must be recognized as conditions a priori of the possibility of experience, whether of intuition, which is found in it, or of thought. Concepts which supply the objective ground of the possibility of experience are for that very reason necessary. An analysis of the experience in which they are found would not be a deduction, but a mere illustration, because they would there have an accidental character only. Nay, without their original relation to all possible experience in which objects of knowledge occur, their relation to any single object would be quite incomprehensible.
[There are three original sources, or call them faculties or powers of the soul, which contain the conditions of the possibility of all experience, and which themselves cannot be derived from any other faculty, namely, sense, imagination, and apperception. On them is founded —
1. The synopsis of the manifold a priori through the senses.
2. The synthesis of this manifold through the imagination.
3. The unity of that synthesis by means of original apperception.
Besides their empirical use all these faculties have a transcendental use also, referring to the form only and possible a priori. With regard to the senses we have discussed that transcendental use in the first part, [p. 95] and we shall now proceed to an investigation of the remaining two, according to their true nature.1 ]
[1 ]That is a transcendental deduction.
[1 ]Read deren instead of dessen.
[1 ]The last paragraph is omitted in the Second Edition. There is instead a criticism of Locke and Hume, Supplement XIII. The Deduction of the Categories is much changed, as seen in Supplement XIV.