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

Secondly, that in order to exhibit change, as the intuition corresponding to the concept of causality, we must use motion as change in space for our example, nay, can thus only gain an intuition of changes the possibihty of which no pure understanding can ever conceive. Change is the connection of contradictory opposites in the existence of one and the same thing. Now, how it is possible that from a given state another state, opposed to it, should arise in the same thing, no reason can comprehend without an example; nay, without an intuition, cannot even render it intelligible to itself. That intuition, however, is that of the motion of a point in space, the presence of which in different places (as a consequence of opposite determinations) gives us, for the first time, an intuition of change : so that, in order to make even internal changes afterwards conceivable to ourselves, we must make time, as the form of the internal sense, figuratively comprehensible to ourselves by means of a line, and the internal the contingency of the motion of a body, we should have to prove that instead of the motion at the antecedent point of time, it would have been possible for the body to have been at rest at that very time, not that it is at rest afterwards ; for in this case both opposites are quite consistent with each other.

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change by means of the drawing of that Hne (motion): in other words, the successive existence of ourselves in different states, by means of an external intuition. The real reason of this lies in the fact that all change presupposes something permanent in intuition, in order that it may itself be perceived as change, while no permanent intuition is to be found in the internal sense.

Thirdly, and lastly, the category of community cannot, so far as its possibility is concerned, be conceived by mere reason alone : and the objective reahty of that concept cannot therefore be possibly understood without intuition, and without external intuition in space.

For how should we conceive the possibility that, when several substances exist, something (as an effect) could follow from the existence of one of them as affecting reciprocally the existence of the other, and that, therefore, because there is something in the former, something must also be in the latter, which, from the existence of the latter alone, could not be understood?

For this is necessary to establish community, though it is utterly inconceivable among things, each of which completely isolates itself through its substantiality. Leibniz, therefore, as he attributed community to the substances of the world, as conceived by the understanding alone, required the interference of a Deity; because, as he justly perceived, such community would have been inconceivable from the existence of such substances only.

We, on the contrary, can render the possibility of such a communion (of substances as phenomena) perfectly conceivable to ourselves, if we represent them to ourselves in space, that is, in external intuition. For space contains, even a priori, formal external relations, as conditions of the possibility of the real relations of action and reaction, that is, of community.

It is easy to show, in the same manner, that the possibility of things as quanta, and therefore, the objective reality of the category of quantity, can be exhibited in external intuition only, and, by means of it alone, be afterwards applied to the internal sense. But, in order to avoid prolixity, I must leave it to the reflection of the reader to find the examples of this.

The whole of these notes is of great importance, not only as confirming our previous refutation of idealism, but even more.

jze

Supplement XXII

when we come to treat of self-knowledge by mere internal consciousness, and the determination of our own nature, without the help of external empirical intuitions, in order to show us the limits of the possibiUty of such knowledge.

The last result of the whole of this section is therefore this : All principles of the pure understanding are nothing more than a priori principles of the possibility of experience ; and to experience alone do all synthetical propositions a priori relate : nay, their possibility itself rests entirely on that relation.

SUPPLEMENT XXIII

[See vol. ii. p. 213]

In one word, none of these concepts admit of being authenticated, nor can their real possibiHty be proved, if all sensuous intuition (the only one which we possess) is removed, and there remains in that case a logical possibility only, that is, that a concept (a thought) is possible. This, however, does not concern us here, but only whether the concept refers to an object and does therefore signify anything.

p. 787

SUPPLEMENT XXIV

[See vol. ii. p. 216]