| A conception of space and time as quanta may be presented a priori in intuition, that is, constructed, either alone with their quality (figure), or as pure quantity (the mere synthesis of the homogeneous), by means of number. |
| But the matter of phenomena, by which things are given in space and time, can be presented only in perception, a posteriorI. The only conception which represents a priori this empirical content of phenomena is the conception of a thing in general; and the a priori synthetical cognition of this conception can give us nothing more than the rule for the synthesis of that which may be contained in the corresponding a posteriori perception; it is utterly inadequate to present an a priori intuition of the real object, which must necessarily be empirical. |
| Synthetical propositions, which relate to things in general, an a priori intuition of which is impossible, are transcendental. |
| For this reason transcendental propositions cannot be framed by means of the construction of conceptions; they are a priori, and based entirely on conceptions themselves. |
| They contain merely the rule, by which we are to seek in the world of perception or experience the synthetical unity of that which cannot be intuited a priorI. But they are incompetent to present any of the conceptions which appear in them in an a priori intuition; these can be given only a posteriori, in experience, which, however, is itself possible only through these synthetical principles. |
| If we are to form a synthetical judgement regarding a conception, we must go beyond it, to the intuition in which it is given. |
| If we keep to what is contained in the conception, the judgement is merely analytical--it is merely an explanation of what we have cogitated in the conception. |
| But I can pass from the conception to the pure or empirical intuition which corresponds to it. |
| I can proceed to examine my conception in concreto, and to cognize, either a priori or a posterio, what I find in the object of the conception. |
| The former--a priori cognition--is rational-mathematical cognition by means of the construction of the conception; the latter--a posteriori cognition--is purely empirical cognition, which does not possess the attributes of necessity and universality. |
| Thus I may analyse the conception I have of gold; but I gain no new information from this analysis, I merely enumerate the different properties which I had connected with the notion indicated by the word. |
| My knowledge has gained in logical clearness and arrangement, but no addition has been made to it. |
| But if I take the matter which is indicated by this name, and submit it to the examination of my senses, I am enabled to form several synthetical--although still empirical- propositions. |
| The mathematical conception of a triangle I should construct, that is, present a priori in intuition, and in this way attain to rational-synthetical cognition. |
| But when the transcendental conception of reality, or substance, or power is presented to my mind, I find that it does not relate to or indicate either an empirical or pure intuition, but that it indicates merely the synthesis of empirical intuitions, which cannot of course be given a priorI. The synthesis in such a conception cannot proceed a priori--without the aid of experience--to the intuition which corresponds to the conception; and, for this reason, none of these conceptions can produce a determinative synthetical proposition, they can never present more than a principle of the synthesis* of possible empirical intuitions. |
| A transcendental proposition is, therefore, a synthetical cognition of reason by means of pure conceptions and the discursive method, and it renders possible all synthetical unity in empirical cognition, though it cannot present us with any intuition a priorI. [*Footnote; In the case of the conception of cause, I do really go beyond the empirical conception of an event--but not to the intuition which presents this conception in concreto, but only to the time-conditions, which may be found in experience to correspond to the conception. |
| My procedure is, therefore, strictly according to conceptions; I cannot in a case of this kind employ the construction of conceptions, because the conception is merely a rule for the synthesis of perceptions, which are not pure intuitions, and which, therefore, cannot be given a priori.] |
| There is thus a twofold exercise of reason. |
| Both modes have the properties of universality and an a priori origin in common, but are, in their procedure, of widely different character. |
| The reason of this is that in the world of phenomena, in which alone objects are presented to our minds, there are two main elements--the form of intuition (space and time), which can be cognized and determined completely a priori, and the matter or content--that which is presented in space and time, and which, consequently, contains a something--an existence corresponding to our powers of sensation. |
| As regards the latter, which can never be given in a determinate mode except by experience, there are no a priori notions which relate to it, except the undetermined conceptions of the synthesis of possible sensations, in so far as these belong (in a possible experience) to the unity of consciousness. |