| As regards the mode of proof which we have employed in treating of these transcendental laws of nature, and the peculiar character of we must make one remark, which will at the same time be important as a guide in every other attempt to demonstrate the truth of intellectual and likewise synthetical propositions a priorI. Had we endeavoured to prove these analogies dogmatically, that is, from conceptions; that is to say, had we employed this method in attempting to show that everything which exists, exists only in that which is permanent--that every thing or event presupposes the existence of something in a preceding state, upon which it follows in conformity with a rule--lastly, that in the manifold, which is coexistent, the states coexist in connection with each other according to a rule- all our labour would have been utterly in vain. |
| For more conceptions of things, analyse them as we may, cannot enable us to conclude from the existence of one object to the existence of another. |
| What other course was left for us to pursue? |
| This only, to demonstrate the possibility of experience as a cognition in which at last all objects must be capable of being presented to us, if the representation of them is to possess any objective reality. |
| Now in this third, this mediating term, the essential form of which consists in the synthetical unity of the apperception of all phenomena, we found a priori conditions of the universal and necessary determination as to time of all existences in the world of phenomena, without which the empirical determination thereof as to time would itself be impossible, and we also discovered rules of synthetical unity a priori, by means of which we could anticipate experience. |
| For want of this method, and from the fancy that it was possible to discover a dogmatical proof of the synthetical propositions which are requisite in the empirical employment of the understanding, has it happened that a proof of the principle of sufficient reason has been so often attempted, and always in vain. |
| The other two analogies nobody has ever thought of, although they have always been silently employed by the mind,* because the guiding thread furnished by the categories was wanting, the guide which alone can enable us to discover every hiatus, both in the system of conceptions and of principles. |
| [*Footnote; The unity of the universe, in which all phenomena to be connected, is evidently a mere consequence of the admitted principle of the community of all substances which are coexistent. |
| For were substances isolated, they could not as parts constitute a whole, and were their connection (reciprocal action of the manifold) not necessary from the very fact of coexistence, we could not conclude from the fact of the latter as a merely ideal relation to the former as a real one. |
| We have, however, shown in its place that community is the proper ground of the possibility of an empirical cognition of coexistence, and that we may therefore properly reason from the latter to the former as its condition.] |
| 4. THE POSTULATES OF EMPIRICAL THOUGHT. |
| 1. That which agrees with the formal conditions (intuition and conception) of experience, is possible. |
| 2. That which coheres with the material conditions of experience (sensation), is real. |
| 3. That whose coherence with the real is determined according to universal conditions of experience is (exists) necessary. |
| Explanation. |
| The categories of modality possess this peculiarity, that they do not in the least determine the object, or enlarge the conception to which they are annexed as predicates, but only express its relation to the faculty of cognition. |
| Though my conception of a thing is in itself complete, I am still entitled to ask whether the object of it is merely possible, or whether it is also real, or, if the latter, whether it is also necessary. |
| But hereby the object itself is not more definitely determined in thought, but the question is only in what relation it, including all its determinations, stands to the understanding and its employment in experience, to the empirical faculty of judgement, and to the reason of its application to experience. |
| For this very reason, too, the categories of modality are nothing more than explanations of the conceptions of possibility, reality, and necessity, as employed in experience, and at the same time, restrictions of all the categories to empirical use alone, not authorizing the transcendental employment of them. |
| For if they are to have something more than a merely logical significance, and to be something more than a mere analytical expression of the form of thought, and to have a relation to things and their possibility, reality, or necessity, they must concern possible experience and its synthetical unity, in which alone objects of cognition can be given. |
| The postulate of the possibility of things requires also, that the conception of the things agree with the formal conditions of our experience in general. |