| There is no danger of our mistaking merely empirical principles for principles of the pure understanding, or conversely; for the character of necessity, according to conceptions which distinguish the latter, and the absence of this in every empirical proposition, how extensively valid soever it may be, is a perfect safeguard against confounding them. |
| There are, however, pure principles a priori, which nevertheless I should not ascribe to the pure understanding--for this reason, that they are not derived from pure conceptions, but (although by the mediation of the understanding) from pure intuitions. |
| But understanding is the faculty of conceptions. |
| Such principles mathematical science possesses, but their application to experience, consequently their objective validity, nay the possibility of such a priori synthetical cognitions (the deduction thereof) rests entirely upon the pure understanding. |
| On this account, I shall not reckon among my principles those of mathematics; though I shall include those upon the possibility and objective validity a priori, of principles of the mathematical science, which, consequently, are to be looked upon as the principle of these, and which proceed from conceptions to intuition, and not from intuition to conceptions. |
| In the application of the pure conceptions of the understanding to possible experience, the employment of their synthesis is either mathematical or dynamical, for it is directed partly on the intuition alone, partly on the existence of a phenomenon. |
| But the a priori conditions of intuition are in relation to a possible experience absolutely necessary, those of the existence of objects of a possible empirical intuition are in themselves contingent. |
| Hence the principles of the mathematical use of the categories will possess a character of absolute necessity, that is, will be apodeictic; those, on the other hand, of the dynamical use, the character of an a priori necessity indeed, but only under the condition of empirical thought in an experience, therefore only mediately and indirectly. |
| Consequently they will not possess that immediate evidence which is peculiar to the former, although their application to experience does not, for that reason, lose its truth and certitude. |
| But of this point we shall be better able to judge at the conclusion of this system of principles. |
| The table of the categories is naturally our guide to the table of principles, because these are nothing else than rules for the objective employment of the former. |
| Accordingly, all principles of the pure understanding are: |
| 1 Axioms of Intuition 2 Anticipations 3 Analogies of Perception of Experience 4 Postulates of Empirical Thought in general |
| These appellations I have chosen advisedly, in order that we might not lose sight of the distinctions in respect of the evidence and the employment of these principles. |
| It will, however, soon appear that--a fact which concerns both the evidence of these principles, and the a priori determination of phenomena--according to the categories of quantity and quality (if we attend merely to the form of these), the principles of these categories are distinguishable from those of the two others, in as much as the former are possessed of an intuitive, but the latter of a merely discursive, though in both instances a complete, certitude. |
| I shall therefore call the former mathematical, and the latter dynamical principles.* It must be observed, however, that by these terms I mean just as little in the one case the principles of mathematics as those of general (physical) dynamics in the other. |
| I have here in view merely the principles of the pure understanding, in their application to the internal sense (without distinction of the representations given therein), by means of which the sciences of mathematics and dynamics become possible. |
| Accordingly, I have named these principles rather with reference to their application than their content; and I shall now proceed to consider them in the order in which they stand in the table. |
| [*Footnote; All combination (conjunctio) is either composition (compositio) or connection (nexus). |
| The former is the synthesis of a manifold, the parts of which do not necessarily belong to each other. |
| For example, the two triangles into which a square is divided by a diagonal, do not necessarily belong to each other, and of this kind is the synthesis of the homogeneous in everything that can be mathematically considered. |