Kant's Critique of Judgement

As we so often find occasion in Transcendental Philosophy for distinguishing Ideas from concepts of the Understanding, it may be of use to introduce technical terms to correspond to this distinction. I believe that no one will object if I propose some.—In the most universal signification of the word, Ideas are representations referred to an object, according to a certain (subjective or objective) principle, but so that they can never become a cognition of it. They are either referred to an intuition, according to a merely subjective principle of the mutual harmony of the cognitive powers (the Imagination and the Understanding), and they are then called aesthetical; or they are referred to a concept according to an objective principle, although they can never furnish a cognition of the object and are called rational Ideas. In the latter case the concept is a transcendent one, which is different from a concept of the Understanding, to which an adequately corresponding experience can always be supplied, and which therefore is called immanent.

An aesthetical Idea cannot become a cognition, because it is an intuition (of the Imagination) for which an adequate concept can never be found. A rational Idea can never become a cognition, because it involves a concept (of the supersensible), corresponding to which an intuition can never be given.

Now I believe we might call the aesthetical Idea an inexponible representation of the Imagination, and a rational Idea an indemonstrable concept of Reason. It is assumed of both that they are not generated without grounds, but (according to the above explanation of an Idea in general) in conformity with certain principles of the cognitive faculties to which they belong (subjective principles in the one case, objective in the other).

Concepts of the Understanding must, as such, always be demonstrable [if by demonstration we understand, as in anatomy, merely presentation];101 i.e. the object corresponding to them must always be capable of being given in intuition (pure or empirical); for thus alone could they become cognitions. The concept of magnitude can be given a priori in the intuition of space, e.g. of a right line, etc.; the concept of cause in impenetrability, in the collision of bodies, etc. Consequently both can be authenticated by means of an empirical intuition, i.e. the thought of them can be proved (demonstrated, verified) by an example; and this must be possible, for otherwise we should not be certain that the concept was not empty, i.e. devoid of any Object.

In Logic we ordinarily use the expressions demonstrable or indemonstrable only in respect of propositions, but these might be better designated by the titles respectively of mediately and immediately certain propositions; for pure Philosophy has also propositions of both kinds, i.e. true propositions, some of which are susceptible of proof and others not. It can, as philosophy, prove them on a priori grounds, but it cannot demonstrate them; unless we wish to depart entirely from the proper meaning of this word, according to which to demonstrate (ostendere, exhibere) is equivalent to presenting a concept in intuition (whether in proof or merely in definition). If the intuition is a priori this is called construction; but if it is empirical, then the Object is displayed by means of which objective reality is assured to the concept. Thus we say of an anatomist that he demonstrates the human eye, if by a dissection of this organ he makes intuitively evident the concept which he has previously treated discursively.

It hence follows that the rational concept of the supersensible substrate of all phenomena in general, or even of that which must be placed at the basis of our arbitrary will in respect of the moral law, viz. of transcendental freedom, is already, in kind, an indemonstrable concept and a rational Idea; while virtue is so, in degree. For there can be given in experience, as regards its quality, absolutely nothing corresponding to the former; whereas in the latter case no empirical product attains to the degree of that causality, which the rational Idea prescribes as the rule.

As in a rational Idea the Imagination with its intuitions does not attain to the given concept, so in an aesthetical Idea the Understanding by its concepts never attains completely to that internal intuition which the Imagination binds up with a given representation. Since, now, to reduce a representation of the Imagination to concepts is the same thing as to expound it, the aesthetical Idea may be called an inexponible representation of the Imagination (in its free play). I shall have occasion in the sequel to say something more of Ideas of this kind; now I only note that both kinds of Ideas, rational and aesthetical, must have their principles; and must have them in Reason—the one in the objective, the other in the subjective principles of its employment.

We can consequently explain genius as the faculty of aesthetical Ideas; by which at the same time is shown the reason why in the products of genius it is the nature (of the subject) and not a premeditated purpose that gives the rule to the art (of the production of the beautiful). For since the beautiful must not be judged by concepts, but by the purposive attuning of the Imagination to agreement with the faculty of concepts in general, it cannot be rule and precept which can serve as the subjective standard of that aesthetical but unconditioned purposiveness in beautiful art, that can rightly claim to please every one. It can only be that in the subject which is nature and cannot be brought under rules or concepts, i.e. the supersensible substrate of all his faculties (to which no concept of the Understanding extends), and consequently that with respect to which it is the final purpose given by the intelligible [part] of our nature to harmonise all our cognitive faculties. Thus alone is it possible that there should be a priori at the basis of this purposiveness, for which we can prescribe no objective principle, a principle subjective and yet of universal validity.