The Three Critiques: The Critique of Pure Reason, The Critique of Practical Reason and The Critique of Judgment (Complete Edition). Immanuel Kant

Thus I do not say that bodies seem or appear to be external to me, or that my soul seems merely to be given in my self-consciousness, although I maintain that the properties of space and time, in conformity to which I set both, as the condition of their existence, abide in my mode of intuition, and not in the objects in themselves. It would be my own fault, if out of that which I should reckon as phenomenon, I made mere illusory appearance.¹⁴ But this will not happen, because of our principle of the ideality of all sensuous intuitions. On the contrary, if we ascribe objective reality to these forms of representation, it becomes impossible to avoid changing everything into mere appearance. For if we regard space and time as properties, which must be found in objects as things in themselves, as sine quibus non of the possibility of their existence, and reflect on the absurdities in which we then find ourselves involved, inasmuch as we are compelled to admit the existence of two infinite things, which are nevertheless not substances, nor anything really inhering in substances, nay, to admit that they are the necessary conditions of the existence of all things, and moreover, that they must continue to exist, although all existing things were annihilated — we cannot blame the good Berkeley for degrading bodies to mere illusory appearances. Nay, even our own existence, which would in this case depend upon the self-existent reality of such a mere nonentity as time, would necessarily be changed with it into mere appearance — an absurdity which no one has as yet been guilty of.

      IV. In natural theology, where we think of an object — God — which never can be an object of intuition to us, and even to himself can never be an object of sensuous intuition, we carefully avoid attributing to his intuition the conditions of space and time — and intuition all his cognition must be, and not thought, which always includes limitation. But with what right can we do this if we make them forms of objects as things in themselves, and such, moreover, as would continue to exist as a priori conditions of the existence of things, even though the things themselves were annihilated? For as conditions of all existence in general, space and time must be conditions of the existence of the Supreme Being also. But if we do not thus make them objective forms of all things, there is no other way left than to make them subjective forms of our mode of intuition — external and internal; which is called sensuous, because it is not primitive, that is, is not such as gives in itself the existence of the object of the intuition (a mode of intuition which, so far as we can judge, can belong only to the Creator), but is dependent on the existence of the object, is possible, therefore, only on condition that the representative faculty of the subject is affected by the object.

      It is, moreover, not necessary that we should limit the mode of intuition in space and time to the sensuous faculty of man. It may well be that all finite thinking beings must necessarily in this respect agree with man (though as to this we cannot decide), but sensibility does not on account of this universality cease to be sensibility, for this very reason, that it is a deduced (intuitus derivativus), and not an original (intuitus originarius), consequently not an intellectual intuition, and this intuition, as such, for reasons above mentioned, seems to belong solely to the Supreme Being, but never to a being dependent, quoad its existence, as well as its intuition (which its existence determines and limits relatively to given objects). This latter remark, however, must be taken only as an illustration, and not as any proof of the truth of our aesthetical theory.

      §§ 10 Conclusion of the Transcendental Aesthetic.

      We have now completely before us one part of the solution of the grand general problem of transcendental philosophy, namely, the question: “How are synthetical propositions a priori possible?” That is to say, we have shown that we are in possession of pure a priori intuitions, namely, space and time, in which we find, when in a judgement a priori we pass out beyond the given conception, something which is not discoverable in that conception, but is certainly found a priori in the intuition which corresponds to the conception, and can be united synthetically with it. But the judgements which these pure intuitions enable us to make, never reach farther than to objects of the senses, and are valid only for objects of possible experience.

¹³ I can indeed say “my representations follow one another, or are successive”; but this means only that we are conscious of them as in a succession, that is, according to the form of the internal sense. Time, therefore, is not a thing in itself, nor is it any objective determination pertaining to, or inherent in things.

¹⁴ The predicates of the phenomenon can be affixed to the object itself in relation to our sensuous faculty; for example, the red colour or the perfume to the rose. But (illusory) appearance never can be attributed as a predicate to an object, for this very reason, that it attributes to this object in itself that which belongs to it only in relation to our sensuous faculty, or to the subject in general, e.g., the two handles which were formerly ascribed to Saturn. That which is never to be found in the object itself, but always in the relation of the object to the subject, and which moreover is inseparable from our representation of the object, we denominate phenomenon. Thus the predicates of space and time are rightly attributed to objects of the senses as such, and in this there is no illusion. On the contrary, if I ascribe redness of the rose as a thing in itself, or to Saturn his handles, or extension to all external objects, considered as things in themselves, without regarding the determinate relation of these objects to the subject, and without limiting my judgement to that relation — then, and then only, arises illusion.

      Second Part. Transcendental Logic.

      Introduction. Idea of a Transcendental Logic.

      I. Of Logic in General.

       Table of Contents

      Our knowledge springs from two main sources in the mind, first of which is the faculty or power of receiving representations (receptivity for impressions); the second is the power of cognizing by means of these representations (spontaneity in the production of conceptions). Through the first an object is given to us; through the second, it is, in relation to the representation (which is a mere determination of the mind), thought. Intuition and conceptions constitute, therefore, the elements of all our knowledge, so that neither conceptions without an intuition in some way corresponding to them, nor intuition without conceptions, can afford us a cognition. Both are either pure or empirical. They are empirical, when sensation (which presupposes the actual presence of the object) is contained in them; and pure, when no sensation is mixed with the representation. Sensations we may call the matter of sensuous cognition. Pure intuition consequently contains merely the form under which something is intuited, and pure conception only the form of the thought of an object. Only pure intuitions and pure conceptions are possible a priori; the empirical only a posteriori.

      We apply the term sensibility to the receptivity of the mind for impressions, in so far as it is in some way affected; and, on the other hand, we call the faculty of spontaneously producing representations, or the spontaneity of cognition, understanding. Our nature is so constituted that intuition with us never can be other than sensuous, that is, it contains only the mode in which we are affected by objects. On the other hand, the faculty of thinking the object of sensuous intuition is the understanding. Neither of these faculties has a preference over the other. Without the sensuous faculty no object would be given to us, and without the understanding no object would be thought. Thoughts without content are void; intuitions without conceptions, blind. Hence it is as necessary for the mind to make its conceptions sensuous (that is, to join to them the object in intuition), as to make its intuitions intelligible (that is, to bring them under conceptions). Neither of these faculties can exchange its proper function. Understanding cannot intuite, and the sensuous faculty cannot think. In no other way than from the united operation of both, can knowledge arise. But no one ought, on this account, to overlook the difference of the elements contributed by each; we have rather great reason carefully to separate and distinguish them. We therefore distinguish the science of the laws of sensibility,