"In the representing of a linden, a beech or a fir as a tree, for example, the particular which is intuited as such and such a thing is determined on the basis of a reference to the sort of thing which 'applies for many'. Indeed, this applicability to many characterizes a representation as concept, but nevertheless does not yet hit upon its original essence. For its part, then, this applicability to many [instances] as a derivative character is grounded in the fact that represented in the concept is the one [das Eine] in which several objects agree...The oneness of this one must allow anticipatively kept in view in conceptual representing, therefore, and it must allow for all assertions concerning the many which are determinative."
Here the weight of the argument turns to the workout of some crucial concepts: the one, the many, determinative, representation and agreement. Heidegger is here calling attention to the fact that representation, for Kant, can be understood in two ways: an essential primordial way, and in a secondary derivative way. In order to clarify, let us proceed systematically, beginning with the unessential, but most obvious, reading:
(1) Representing an object concerns conceptually grasping those universals which identify the object represented as such. For example, to represent a tree, to account for what a tree is conceptually, means to represent branches, leaves, wood, etc. These are the concepts which in assertion determine what my representation is about, i.e. the universals under which I identify the content of my representation. Therefore, to representation, qua conceptual understanding, belongs the identification of some universal quality which applies universally to many, to all objects of its kind: for my representation to be about trees means that in asserting I refer to the universal under which one may recognize this particular as an instance of the universal uttered. This is not to say that there ought to be more than one actual tree in existence, but merely that representing through concepts concerns allowing for many objects to occur as instances of itself. To say my thought is about a tree means that it is about the sort of thing all other trees could be, sharing conceptually with other trees what belongs to the particular as just an instantiation of what belongs uniquely to the concept of a tree- i.e. things with branches, made of wood, belonging to the kingdom of plants, and so on. But because this particular character is at the same time a universal that applies to many it is a one only insofar as it can keep in view how different entities must belong to this universal. Concepts thus determine what the object is by means of placing it under the rubric of the universal which refers to other objects of a kind. This is what Heidegger means by representation conceptually being based on seeing the many in one. Thus the classic Kantian point should be echoed that¨"it is mere tautology to speak of universal of common concepts¨. These concepts must already involve a reflection in order to occur in a consciousness (is not this basic necessary correlation between the universal as the unifying of the many under the rubric of one consciousness precisely what in Absolute Idealism allows for the sublation from consciousness to self-consciousness, and then to spirit?).This is why, for Heidegger, reflection in the sense of concept assigning, determines the content of the representing- whatness (Sachheit).
(2) However, this meaning can only be derivative; since pure conceptual representation must cannot be found just in any particular instance (appearance). This pure conceptual content must be obtainable a priori, read as a pure function capable of determining the given intuition. This raises a fundamental problem, since the pure concept 'the one' object in its unity. Before this fragmented conceptual representation, there is a primordial grasping of the unity to which all conceptual determinations belong. Here we should resist reading Heidegger (and Kant) as underlining the point that the whole not apprehended merely as the sum of its parts, i.e. the tree is not grasped first as a collection of branches, leaves and oak, but is seen undifferentiated in its concrete unity as a thing. We are all familiar with the kind of Quinean problems that stem from these sort of considerations, and we say nothing of interest here by just repeating them. The proper reading is in direct continuity with Heidegger's earlier point that the 'thing-itself' is not the unknown object behind appearances (noumenon), but the thing itself as it can only appear as appearance in finite knowing. That is to say, that the representation of objects qua appearances, by being subservient to the being which it did not itself produce, belongs a fundamental incompleteness, a certain lack which embodies the substance of the 'thing itself' as that which resists the symbolic representing; and thus remains outside the scope of finite knowledge (as we know, Kant later attributes this primordial unifying of intuition-understanding as Transcendental Apperception).
What Heidegger has in mind is thus not that underlying my conceptual fragmentation of the thing under the universals which relate it to other objects lies a 'real' thing outside of my cognitive faculties; but more radically, that 'the one' is precisely that which must be pressuposed as resisting conceptualization- not because it is beyond our primitive reach as finite thinking creatures, but because it is essential to the conceptually determined object that it be only given as appearances, in an incomplete, inherently fragmented character- from the conceptual 'many in one'.
This is not to echo Deleuze's point that at first we have a 'plurality' as would be, for example, the amalgamate of possible predicates attributed to any object which precede the object's unity as such. On the contrary, here Heidegger and Kant can be read off as making the same point as Lacan makes when he states that the Real is the surplus which both results and causes symbolization; that conceptualization is therefore not only never in touch with the 'the one', but that 'the one' is nothing but this gap between the determinative conceptual plurality of the symbolic and the traumatic real which can never be attained. It is precisely the peculiarity of finite thinking that it should suffer this gap as the objective because it must intuit that which it did not bring into being. That which just lies there and can only be approached from the understanding through concepts is the circumventing around the Real object as a mere phantom, as the gap, the lack or the incompleteness which is proper to the appearance. This lack/surplus has as of recently been developed in Zizek's 'The Parallax View' in more substantive detail.
This 'keeping in view the one object', as above the particularizations granted by conceptual, determinative thinking, is what Kant calls 'Reflection'. But 'keeping in view' here does not mean, of course, that the subject apprehends the object preconceptually and remembers it; but refers to the moment where the subject is immediatly introduced into the symbolic order, the initial trauma where "the deliberation whereby representations can be grasped in one consciousness". This unity is, of course, fulfilling the function of uniting the many under the one, of potentially unleashing the symbolic order in motion. Heidegger is well aware of this function in Kant:
"...with reference to this oneness the many can be likened to one another... in the concept, something is not merely represented which tactically belongs to many; instead it is this belonging, insofar as it belongs, in its oneness. [which is represented]". This is to say, representation does not grasp the object first to then apply concepts to it, but the object is only there as the remainder, the surplus which resists symbolization and to which the conceptual must refer in order to be determinable. Concepts, in order to sustain themselves as meaningful, must refer to 'the one' object under which they are laden, and to the constitutive excess which sets the symbolic order in motion. This and nothing else is the Real of the object.