I established in the last two posts (here and here) that how the thing-in-itself operates within Kant’s system is rather difficult to pin down; in addition to this, what the phrase means is also quite ambiguous since Kant uses a number of different locutions to seemingly refer to the same thing. Furthermore, Kant discusses the subject at both the beginning and the end of the first division, and it is not clear that he is referring to the same thing in both places. That said, I want to emphasize again that this reading of the thing-in-itself is set forth and utilized in order to best show the distinction between knowledge of things-in-themselves and knowledge that comes from objective judgments, which we’ll get to in the next (and final) post on reason in Kant.
The primary issue at hand for Kant is to explain both how objects in our sensible intuitions are only as they appear and how it is that his system is not simply a version of Berkeleian idealism in which there are no empirically real objects at all, only ideas. Kant first introduces the idea of appearances contrasted with objects as they are in the Transcendental Aesthetic. Objects cannot be given to us any other way but through intuition (A19/B33), and Kant calls these given objects appearances. In the Transcendental Aesthetic, he establishes both space and time as a priori conditions of the possibility of intuition, with space as the outer sense of intuition and time the inner sense. They are the form of all intuition—they make appearances possible. Space and time are therefore not themselves appearances or empirical concepts that come from experience but the form of experience without which we could not have sensible intuitions. Most importantly for our present concern, space and time do not apply to objects in themselves. We know a priori that space and time give us the form of objects as they appear to us, since “One can never represent that there is no space, although one can very well think that there are no objects to be encountered in it [. . .] [and] In regard to appearances in general one cannot remove time, though one can very well take the appearances away from time” (A24/B38, A31/B46).
In other words, we simply cannot think outside of these forms. They are for us. If space and time are the form of our intuition and we accept that there are empirically real objects that we intuit as appearances, it follows that those objects exist as they do not appear to us as well. We can think them that way (or “consider” them as Allison says) because we know that our intuitions are of objects as they appear to us according to the form of space and time. In this way, thing-in-itself is a contrasting place-holder. We cannot know anything about objects as they really are because we would have to know them outside of space and time. However, this does not prevent us from saying that the same objects exist independentally of our intuitions—refuting that that would be to commit to idealism. We can thus say that the thing-in-itself as aspect is a methodology in that it is the counter to the thing as it appears to us in space and time that helps us square the existence of empirically real objects with the premise that the intuition of objects can only be appearances given that the ground of all intuition is space and time, an a priori pure intuition. In Kant’s conclusion to the Transcendental Analytic, he surveys all that he has covered and returns to the ideas of appearance and thing-in-itself. In the A edition, Kant reintroduces the phenomena/noumena terminology from the Dissertation (discussed in my first post) initially giving a summary of his claim from it. He writes:
Appearances, to the extent that as objects they are thought in accordance with the unity of the categories, are called phenomena. If, however, I suppose there to be things that are merely objects of the understanding and that, nevertheless, can be given to an intuition, although not to sensible intuition (as coram intuiti intellectuali), then such things would be called noumena (intelligibilia). [. . .] For if the senses merely represent something to us as it appears, then this something must also be in itself a thing, and an object of a non-sensible intuition, i.e., of the understanding, i.e., a cognition must be possible in which no sensibility is encountered, and which alone has absolutely objective reality, through which, namely, objects are represented to us as they are, in contrast to the empirical use of our understanding, in which things are only cognized as they appear. Thus there would be, in addition to the empirical use of the categories (which is limited to sensible conditions), a pure and yet objectively valid one, and we could not assert, what we have previously maintained, that our pure cognitions of the understanding are in general nothing more than principles of the exposition of appearances that do not go a priori beyond the formal possibility of experience, for here an entirely different field would stand open before us, as it were a world though in spirit (perhaps also even intuited), which could not less but even more nobly occupy our understanding (A248-9).
His initial description of noumena found in the Dissertation cannot possibly be correct; otherwise, to paraphrase Kant here, we could not assert that the categories are rules by which we unify the manifold of sensation and do not exceed the a priori formal conditions of space and time which make sense experience possible. His previous understanding of the noumena as non-sensical intuition (i.e. what he had previously called intelligence) does not have a place in a system of transcendentally ideal, empirically real categories in which all intuition is sense experience. Kant reconfigures the terms, writing:
All our representations are in fact related to some object through the understanding, and, since appearances are nothing but representations, the understanding thus relates them to a something, as the object of sensible intuition: but this something is to that extent only the transcendental object. This signifies, however as something = X, of which we know nothing at all nor can know anything in general [. . .], but is rather something that can serve only as a correlate of the unity of apperception for the unity of the manifold in sensible intuition, by means of which the understanding unifies that in the concept of an object. This transcendental object cannot even be separated from the sensible data, for then nothing would remain through which it would be thought. It is therefore no object of cognition in itself, but only the representation of appearances under the concept of an object in general which is determinable through the manifold of those appearances. Just for this reason, then, the categories do not represent any special object given to the understanding alone, but rather serve only to determine the transcendental object [. . .] through that which is given in sensibility, in order thereby to cognize appearances empirically under concepts of objects (A250-1).
We have now a reasonably clear understanding of both the definition and function of the thing-in-itself for Kant. It is a methodological concept that is the necessary result of recognizing that the objects of our intuitions are appearances which conform to the pure intuitions of space and time a priori. In my final post on reason in Kant, we’ll look at his understanding of objective judgments to see how that differs from knowledge of things-in-themselves.