“...we can conclude from the universal to the particular, only if universal qualities are ascribed to things as the foundation upon which the particular qualities rest.”[1657] “The foundation of these laws [cf. below, pp. 550-1] is not due to any secret design of making an experiment by putting them forward as merely tentative suggestions.... It is easily seen that they contemplate the parsimony of fundamental causes, the manifoldness of effects, and the consequent affinity of the parts of nature, as being in themselves both rational and natural. Hence these principles carry their recommendation directly in themselves, and not merely as methodological devices.”[1658]
Thus, in direct opposition to the preceding view of Reason’s function as hypothetical, Kant is now prepared to maintain that the maxims of Reason are without meaning and without application save in so far as they can be grounded in a transcendental principle.[1659]
Let us follow Kant’s detailed exposition of this last thesis. The logical maxim, to seek for systematic unity, rests upon the transcendental principle that the apparently infinite variety of nature does not exclude identity of species, that the various species are varieties of a few genera, and these again of still higher genera. This is the scholastic maxim: entia praeter necessitatem non esse multiplicanda. Upon this principle rests the possibility of concepts, and therefore of the understanding itself. It is balanced, however, by a second principle, no less necessary, the transcendental law of specification, namely, that there must be manifoldness and diversity in things, that every genus must specify itself in divergent species, and these again in sub-species. Or as it is expressed in its scholastic form: entium varietates non temere esse minuendas. This principle is equally transcendental. It expresses a condition no less necessary for the possibility of the understanding, and therefore of experience. As the understanding knows all that it knows by concepts only, however far it may carry the division of genera, it can never know by means of pure intuition, but always again by lower concepts. If, therefore, there were no lower concepts, there could be no higher concepts;[1660] the gap existing between individuals and genera could never be bridged; or rather, since neither individuals nor universals could then be apprehended, neither would exist for the mind. As the higher concepts acquire all their content from the lower, they presuppose them for their own existence.
“Every concept may be regarded as a point which, in so far as it represents the standpoint of a spectator, has its own horizon.... This horizon must be capable of containing an infinite number of points, each of which again has its own narrower horizon; that is, every species contains sub-species, according to the principle of specification, and the logical horizon consists exclusively of smaller horizons (sub-species), never of points which possess no extent (individuals).”[1661]
Combining these two principles, that of homogeneity and that of specification, we obtain a third, that of continuity. The logical law of the continuum formarum logicarum presupposes the transcendental law, lex continui in natura. It provides that homogeneity be combined with the greatest possible diversity by prescribing a continuous transition from every species to every other, or in other words by requiring that between any two species or sub-species, however closely related, intermediate species be always regarded as possible. (The paragraph at the end of A 661 = B 689, with its proviso that we cannot make any definite empirical use of this law, is probably of later origin; it connects with the concluding parts of the section.) That this third law is also a priori and transcendental, is shown by the fact that it is not derived from the prior discovery of system in nature, but has itself given rise to the systematised character of our knowledge.[1662]
The psychological, chemical, and astronomical examples which Kant employs to illustrate these laws call for no special comment. They were taken from contemporary science, and in the advance of our knowledge have become more confusing than helpful. The citation in A 646 = B 674 of the concepts of “pure earth, pure water, pure air” as being “concepts of Reason” is especially bewildering. They are, even in the use which Kant himself ascribes to them, simply empirical hypotheses, formulated for the purposes of purely physical explanation; they are in no genuine sense universal, regulative principles.
In passing to A 663-8 = B 691-6 we find still another variation in the substance of Kant’s teaching. He returns, though with a greater maturity of statement, and with a very different and much more satisfactory terminology, to the more sceptical view of A 646-9 = B 674-7.[1663] The interest of the above principles, Kant continues to maintain, lies in their transcendentality. Despite the fact that they are mere Ideas for the guidance of understanding, and can only be approached asymptotically, they are synthetic a priori judgments, and would seem to have an objective, though indeterminate, validity. So far his statements are in line with the preceding paragraphs. But he proceeds to add that this objective validity consists exclusively in their heuristic function. They differ fundamentally from the dynamical, no less than from the mathematical, principles of understanding, in that no schema of sensibility can be assigned to them. In other words, their object can never be exhibited in concreto; it transcends all possible experience. For this reason they are incapable of a transcendental deduction.[1664] They are among the conditions indispensably necessary to the possibility, not of each and every experience, but only of experience as systematised in the interest of Reason. In place of a schema they can possess only what may be called the analogon of a schema, that is, they represent the Idea of a maximum, which the understanding in the subjective interest of Reason—or, otherwise expressed,[1665] in the interest of a certain possible perfection of our knowledge of objects—is called upon to realise as much as possible. Thus they are at once subjective in the source from which they arise, and also indeterminate as to the conditions under which, and the extent to which, they can obtain empirical embodiment. The fact that in this capacity they represent a maximum, does not justify any assertion either as to the degree of unity which experience on detailed investigation will ultimately be found to verify, or as to the noumenal reality by which experience is conditioned.
In A 644-5 = B 672-3 Kant employs certain optical analogies to illustrate the illusion which the Ideas, in the absence of Critical teaching, inevitably generate. When the understanding is regulated by the Idea of a maximum, and seeks to view all the lines of experience as converging upon and pointing to it, it necessarily regards it, focus imaginarius though it be, as actually existing. The illusion, by which objects are seen behind the surface of a mirror, is indispensably necessary if we are to be able to see what lies behind our backs. The transcendental illusion, which confers reality upon the Ideas of Reason, is similarly incidental to the attempt to view experience in its greatest possible extension.
ON THE FINAL PURPOSE OF THE NATURAL DIALECTIC OF HUMAN REASON[1666]
This section is thoroughly unified and consistent in its teaching. Its repetitious character is doubtless due to Kant’s personal difficulty either in definitively accepting or in altogether rejecting the constructive, Idealist interpretation of the function of Reason. He at least succeeds in formulating a view which, while not asserting anything more than is required in the scientific extension of experience, indicates the many possibilities which such experience fails to exclude. As the Ideas of Reason are not merely empty thought-entities (entia rationis ratiocinantis[1667]), but have a certain kind of objective validity (i.e. are entia rationis ratiocinatae[1668]), they demand a transcendental deduction.[1669] What this deduction is, and how it differs from that of the categories, we must now determine. Its discovery will, Kant claims, crown and complete our Critical labours.