This contingent bond of union however is wholly wanting in eyn Oldie judgments d priori. For instance, in the position, " whatever happens has a cause," tho notion of a cause is not contained in the subject " whatever happens," and it indicates something very different from it. /low then, and by what means, are we enabled to say of "whatever happens" something absolutely different from it, and to recognise " cause," although not contained in it, as necessarily belong ing to it / What is that unknown principle (=X) on which the under standing relies, when of the subject A it finds a foreign predicate B, and believes itself justified in weeding their necessary connection 1 It cannot be experience, since in the above proposition the conception of a casino is attached to the subject, not merely generally, but versally and necessarily. Now all speculative Et priori knowledge ultimately rests upon such synthetic or extending judgments ; for though the analytical are highly important and requisite for science, still their importance is mainly derived from their being indispensable to a wide and legitimate synthesis, whereby alone a new acquisition in science can be made. The proper problem therefore of the pure reason is contained in the question—how are synthetic judgments d priori possible ! With a view to resolve this problem of the pure reason Kant begins with an exposition of the transcendental elements of knowledge (transcendental elementarlehre). By transcendental he understood original or primary, or whatever is determined d priori in reference not only to human cognition but also to man's collective activity, and which consequently is the basis of the empirical, or that which is determined d posteriori. In short, all pure knowledge makes up the transcendental philosophy, and on it rest the authority and possibility of cognition. The elementarlehre is divided into the transcendental aesthetic and the transcendental logic. In the former Kant investigates the d priori elements of the lowest cognitive faculty—sensation ; in the latter, those of the understanding and of the reason. In the aesthetic he shows that the sensuous faculty receives the matter of its intuitions and sensations from without by means of certain affections or excitements of the sense, whereas the forms according to or by means of which this matter is shaped into representations or concep tions of determinate objects are given originally and by itself. These forms are the pure intuitions of space and time, because in them nothing else is intuitively viewed than the unity of that which is multiple either in succession or in co-existence. On this account he calls time and space forms of intuition, and designates the objects which we so intuitively view by the name of phenomena. Of the ground of these phenomena, or, as Kant termed it, the thing in and by itself, it is left doubtful and undetermined whether it is anything actual or not, notwithstanding that Kant ascribes to phenomena themselves a certain objectivity or reality, on the ground that from their constancy and regularity they cannot be a mere semblance or illusion of the senses. On this account his theory has been called a transcendental idealism, as being in nowise inconsistent with that system of empirical realism which by our conduct in life we practically maintain.
Transcendental logic is divided into analytic and dialectic, of which the former is the critic, or investigation of the understanding, as the faculty of notions ; the latter, of the reason, as the faculty of ideas. In the analytic we are taught that it is only when objects have been conceived by the understanding agreeably to its laws, that they can become an object of knowledge. The operations of the understand ing are confined to analysis and synthesis, where however every analysis presupposes a synthesis. A combination of the multiple into unity constitutes a notion (begriff ), and the underatandiug is therefore the faculty of notions. The law of the forms of these notions, irrespective of their contents, is investigated by logic in general, whereas the investigation of these notions in reference to their contents is the proper office of transcendental logic. Notions are either pure or empirical : the former indicating merely the nature and the manner of their combination : the latter, the multiple matter presented by experience. Both are equally necessary to knowledge, for the pure notion is an empty thing apart from the representations, and the latter without the former are blind (' Kritik d. rein. Vern,
p. 55). As sensation only receives matter upon the affection of the senses, it is a mere receptivity, whereas the understanding, which subsumes the given multiple into unity, is a spontaneity. The con sciousness of the individual in this multiplicity is effected by the imagination, which combines them into a whole; whereas the unity, by which the multiplicity, as sensuously perceived, is recognised as an object, is a work of the understanding. Now this unity constitutes the form of the notion, which therefore is the peculiar creation of the understanding. As these forms are different, a complete enumeration of them conformable to some stable principle is necessary in order to n discovery of the laws of knowledge by the understanding. Now all the primary modes of the operations of the understanding, whereby objective unity is imparted to the perceived matter, may be reduced to one of these four : quantity, quality, relation, and modality. These with their subordinates, Kant denominates categories after Aristotle, as determining in and by themselves what in general and antecedently (a priori) may be predicated of objects.
The three categories of quantity are unity, multitude, and totality ; those of quality, reality, negation, and limitation. Those of relation are double and are paired together, as substance and'accident, cause and effect, action and re-action. Lastly, the subordinates of modality are possibility, existence, and necessity.
The process by which these twelve categories, or pure notions of the understanding, are combined with space and time, the pure intuitions of sensation, and thereby presented to knowledge in their possible application to the objects of sense, Kant calls schematism (crxnaaricrads). For instance, the notion of substance is said to be schematised, when it is not conceived of absolutely as a self-subsisting thing, but as one which persists in time, and therefore as a conetaut and persisting sub strate of certain variable qualities or determinations. Notions thus rendered sensible are called schematised, in opposition to the pure categories. In this process the imagination co-operates with the understanding, and its action is original and necessary, since its activity is inseparably bound up with the primary images of space and time. Out of this schematism of notions and the judgments which arise from their combination, the grand principles which regu late the operations of the understanding result. These judgments are either analytical or synthetical. The grand principle of the former, in which identity affords the connection between the subject and the predicate, is the principle of contradiction. The mere absence how ever of contradiction is not sufficient to legitimate the object-matter of any proposition, since there may easily be a synthesis of notions which is not grounded in objects, notwithstanding that it is not incon sistent to conceive. In synthetic judgments, on the other hand, we go beyond the notion which forms the subject, and we ascribe to it a predicate, the connection of which with the subject does not appear immediately from the judgmeut itself. The possibility of this syn thesis implies a medium on which it may rest, and this is the unity of the synthesis in truth d priori. The following is the ultimate prin ciple of synthetic judgments :—All objects are subject to the neces sary conditions of the synthetic unity of the multiple objects of intuition in a possible experience. As this unity is established according to the table of categories, there must be as many pure synthetic principles as categories, and the different characters of their application must depend upon the different characters of the latter. These are either mathematical, and relate to the possibility of intuition, or dynamical, and relate to the existence of phenomena. Accordingly, the principles of the understanding are, relatively to their use, either mathematical or dynamical. The former are unconditionally neces sary, since the possibility of intuition depends upon them; the latter only conditionally necessary, for so far as concerns the existence of phenomena, which for a possible experience is contingent, they imply the condition of empirical thought, notwithstanding that in their application to it they invariably maintain their d priori necessity.