Space and time are the forms of all possible intuition. They are presentation, as concepts are representation. What is given in space and time is reformulated in and by my cognitive faculties. It is through the spontaneity of thought that the multiplicity or manyness that is given by intuition is unified. The spontaneous action of thought upon what is given to it. The very notion of a concept is that it is a thing which unifies a multiplicity. What is this? How does it occur?
We have three integral parts of this process identified by Kant. Each is a synthesis and together they are a synthesis. First is apprehension: that which gathers together this manifold (multiplicity) given to it. You see a part of something, perhaps touch a part of it and there is a certain smell and so on. Second is reproduction in the imagination: that which calls up various prior representations while beholding the current and, according to its rule, places them in a kind of conceptual relation to one another, as the preliminary movement in full conjunction with the apprehension. You see another part of the thing, and as you run your gaze across it you simultaneously call up that which you saw before using the imagination (which here does not carry the common sense of the term as that which creates fancy) and in a continuous movement these representations are related to one another, they are held together. Third is recognition in the concept: The only way by which representations acquire any sense or relation to any others is by the unity of consciousness.
There could be no unification of the multiplicity if it were not for the mechanism by which I apprehend and reproduce and relate prior apprehensions and current and in this, for it to function, at its very heart, must lie the I. That which I saw before and that which I am seeing now are unified in that I saw them, me. The correlate of all of my representations is me. It is the unity of my intuitions as my intuitions that must hold the entire thing together and allow this relation, allow the synthesis of the multiplicity of representations. This is Descartes’s “I think” and it must precede any representation that can be said to be anything at all to me.
This occurs by the relation of the determinations I have made in space and time to the pure form of the object. When I apprehend, I do not apprehend objects. Objects are, as of yet, nothing. It is this pure form of the object (Kant gives the formula for this as object = x) that I must relate representations to. We cannot intuit beyond the representation for we cannot penetrate the noumenal. So this something which I had been looking at, first one part then another, appehended and reproduced and finally recognized! I say of it: its a mountain. Or a tree. Or whatever it is. But how?
Through the transcendental apperception, the consciousness of myself, the consciousness of myself as that which is apprehending and reproducing is the foundation of the unification of the multiplicity and the transcendental object is, like everything transcendental, a priori the rule by which my mental activity occurs. Thus, as Deleuze says, “it is my perception which presupposes the object-form as one of its conditions, it’s not something, it’s an empty form.”
And this relation of determinations of space and time to the object = x is recognition in the concept. To allow Deleuze to speak further as he is a great explainer of Kant:
I effect a recognition when I say: “it’s this”. But “it’s this” implies an operation whereby I go beyond what is given to me, I go beyond the forms of space and time, I go beyond purely spatio-temporal forms towards the form of an any-object-whatever that the spatio-temporal form will determine as such or such an object. But just as the two first acts of the synthesis, apprehension and reproduction, refer to the imagination, because it consists in determining a space and a time, so recognition is an act of the understanding. Why? You remember the concepts which are the representations of the understanding, they are the predicates of the any-object-whatever, of the object = x. Not every object is a lion, not every object is red, but every object has a cause, every object is one, every object is a multiplicity of parts, etc…. The predicates that you can attribute to any-object-whatever are the categories of the understanding, they are the concepts of the understanding. So recognition, the form of recognition, the form of the any-object-whatever is no longer in this case the synthesis of the imagination but the unity of the synthesis of ????? [understanding?].
The thoroughgoing and synthetic unity of perceptions is precisely what constitutes the form of experience, and it is nothing other than the synthetic unity of the appearances in accordance with objects…However, the possibility, indeed even the necessity of these categories rests on the relation that the entire sensibility, and with it also all possible appearances, have to the original apperception, in which everything is necessarily in agreement with the conditions of the thoroughgoing unity of self-consciousness, i.e., must stand under universal functions of synthesis, namely of the synthesis in accordance with concepts, as that in which alone apperception can demonstrate a priori its thoroughgoing and necessary identity. Thus the concept of a cause is nothing other than a synthesis (of that which follows in the temporal series with other appearances) in accordance with concepts; and without that sort of unity, which has its rule a priori, and which subjects the appearances to itself, thoroughgoing and universal, hence necessary unity of consciousness would not be encountered in the manifold perceptions. But these would then belong to no experience, and would consequently be without an object, and would be nothing but a blind play of representations, i.e., less than a dream.