Immanuel Kant's Critique of Pure Reason — trans. F. Max Müller

The examples of mathematics and natural science, which byone revolution have become what they now are, seem [p. xvi] to me sufficiently remarkable to induce us to consider, what may have been the essential element in that intellectual revolution which has proved so beneficial to them, and to make the experiment, at least, so far as the analogy between them, as sciences of reason, with metaphysic allows it, of imitating them.

Hitherto it has been supposed that all our knowledge must conform to the objects : but, under that supposition, all attempts to establish anything about them a priori, by means of concepts, and thus to enlarge our knowledge, have come to nothing.

The experiment therefore ought to be made, whether we should not succeed better with the problems of metaphysic, by assuming that the objects must conform to our mode of cognition, for this would better agree with the demanded possibiHty of an a priori knowledge of them, which is to settle something about objects, before they are given us.

We have here the same case as with the first thought of Copernicus, who, not being able to get on in the explanation of the movements of the heavenly bodies, as long as he assumed that all the stars turned round the spectator, tried, whether he could not succeed better, by assuming the spectator to be turning round, and the stars to be at rest.

A similar experiment may be tried in metaphysic, so far as the intuition of objects is [p. xvii] concerned. If the intuition had to conform to the constitution of objects, I do not see how we could know anything of it a priori ; but if the object (as an object of the senses) conforms to the constitution of our faculty of intuition, I can very well conceive such a possibility.

As, however, I cannot rest in these intuitions, if they are to become knowledge, but have. to refer them, as representations, to something as their object, and must determine that object by them, I have the choice of admitting, either that the concepts, by which I carry out that determination, conform to the object, being then again in the same perplexity on account of the manner how I can know anything about it a priori ; or that the objects, or what is the same, the experience in which alone they are known (as given objects), must conform to those concepts. In the latter case, the solution becomes more easy,

694 Siipplemejit II because experience, as a kind of knowledge, requires understanding, and I must therefore, even before objects are given to me, presuppose the rules of the understanding as existing within me a priori, these rules being expressed in concepts a priori, to which all objects of experience must necessarily conform, and with which they must agree. With regard to objects, [p. xviii] so far as they are conceived by reason only, and conceived as necessary, and which can never be given in experience, at least in that form in which they are conceived by reason, we shall find that the attempts at conceiving them (for they must admit of being conceived) will furnish afterwards an excellent test of our new method of thought, according to which we do not know of things anything a priori except what we ourselves put into them.^ ,

This experiment succeeds as well as we could desire, and promises to metaphysic, in its first part, which deals with concepts a priori, of which the corresponding objects may be given in experience, the secure method of a science. For by [p. xix] thus changing our point of view, the possibility of knowledge a priori can well be explained, and, what is still more, the laws which a priori lie at the foundation of nature, as the sum total of the objects of experience, may be supplied with satisfactory proofs, neither of which was possible with the procedure hitherto

1 This method, borrowed from the student of nature, consists in our looking for the elements of pure reason in that which can be confirmed or refuted by experiment. Now it is impossible, in order to test the propositions of pure reason, particularly if they venture beyond all the limits of possible experience, to make any experiment with their objects (as in natural science) ; we can therefore only try with concepts and propositions which we admit a priori, by so contriving that the same objects may be considered on one side as objects of the senses and of the understanding in experience, and, on the other, as objects which are only thought, intended, it may be, for the isolated reason which strives to go beyond all the limits of experience. This gives us two different sides to be looked at ; and if we find that, by looking on things from that twofold point of view, there is an agreement with the principle of pure reason, while by admitting one point of view only, there arises an inevitable conflict with reason, then the experiment decides in favour of the correctness of that distinction.

Supplement II 695