Comment.—These concluding remarks cannot be accepted as representing Kant’s true teaching. The Ideal, by his own showing, is by no means without a flaw. In so far as it involves the concept of unconditioned necessity, it is meaningless; it is purely logical, and therefore contains no indication of real content; it embodies a false view of the nature of negation, and therefore of the relation of realities to one another. In short, it is constituted in accordance with the false, un-Critical principles of Leibnizian metaphysics, and is found on examination to be non-existent even as a purely mental entity. Reduced to its proper terms, it becomes a mere schema regulative of the understanding in the extension of experience, and does not yield even a negative criterion for the testing of our ideals of Divine Existence. The criterion, which Kant really so employs, is not that of an Ens realissimum, but the concept of an Intuitive Understanding, which, as he has indicated in the chapter on Phenomena and Noumena,[1635] is our most adequate Ideal of completed Perfection. This latter is not itself, however, a spontaneously formed concept of natural Reason, and does not justify the assertion that the Idea of God is a necessary Idea of the human mind. In attempting to defend such a thesis, Kant is unduly influenced by the almost universal acceptance of deistic beliefs in the Europe of his time.[1636] His criticism of the Ideal of Reason and of rational theology is much more destructive, and really allows that theology much less value, even as natural dialectic, than he is willing to admit.[1637] Architectonic forbids that the extreme radical consequences of the teaching of the Analytic should be allowed to show in their full force. These shortcomings are, however, in great part remedied in the elaborate Appendix which Kant has attached to the Dialectic.
APPENDIX TO THE TRANSCENDENTAL DIALECTIC
THE REGULATIVE EMPLOYMENT OF THE IDEAS OF PURE REASON[1638]
Before we proceed to deal with this Appendix it will be of advantage to consider the section in the Methodology on the Discipline of Pure Reason in regard to Hypotheses.[1639] That section affords a very illuminating introduction to the problems here discussed, and is extremely important for understanding Kant’s view of metaphysical science as yielding either complete certainty or else nothing at all. This is a doctrine which he from time to time suggests, to the considerable bewilderment of the modern reader.[1640] In discussing it he starts from the obvious objection, that though nothing can be known through Reason in its pure a priori employment, metaphysics may yet be possible in an empirical form, as consisting of hypotheses, constructed in conjectural explanation of the facts of experience. Kant replies by defining the conditions under which alone hypotheses can be entertained as such. There must always be something completely certain, and not only invented or merely “opined,” namely, the possibility of the object to which the hypothesis appeals. Once that is proved, it is allowable, on the basis of experience, to form opinions regarding its reality. Then, and only then, can such opinions be entitled hypotheses. Otherwise we are not employing the understanding to explain; we are simply indulging the imagination in its tendency to dream. Now since the categories of the pure understanding do not enable us to invent a priori the concept of a dynamical connection, but only to apprehend it when presented in experience, we cannot by means of these categories invent a single object endowed with a new quality not empirically given; and cannot, therefore, base an hypothesis upon any such conception.
“Thus it is not permissible to invent any new original powers, as, for instance, an understanding capable of intuiting its objects without the aid of senses; or a force of attraction without any contact; or a new kind of substance existing in space and yet not impenetrable. Nor is it legitimate to postulate any other form of communion of substances than that revealed in experience, any presence that is not spatial, any duration that is not temporal. In a word our Reason can employ as conditions of the possibility of things only the conditions of possible experience; it can never, as it were, create concepts of things, independently of those conditions. Such concepts, though not self-contradictory, would be without an object.”[1641]
This does not, however, mean that the concepts of pure Reason can have no valid employment. They are, it is true, Ideas merely, with no object corresponding to them in any experience; but then it is also true that they are not hypotheses, referring to imagined objects, supposed to be possibly real. They are purely problematic. They are heuristic fictions (heuristische Fiktionen), the sole function of which is to serve as principles regulative of the understanding in its systematic employment. Used in any other manner they reduce to the level of merely mental entities (Gedankendinge) whose very possibility is indemonstrable, and which cannot therefore be employed as hypotheses for the explanation of appearances. Given appearances can be accounted for only in terms of laws known to hold among appearances. To explain natural phenomena by a transcendental hypothesis—mental processes by the assumption of the soul as a substantial, simple, spiritual being, or order and design in nature by the assumption of a Divine Author—is never admissible.
“...that would be to explain something, which in terms of known empirical principles we do not understand sufficiently, by something which we do not understand at all.”[1642]
And Kant adds that the wildest hypotheses, if only they are physical, are more tolerable than a hyperphysical one. They at least conform to the conditions under which alone hypothetical explanation as such is allowable. “Outside this field, to form opinions, is merely to play with thoughts....”[1643]
A further condition, required to render an hypothesis acceptable, is its adequacy for determining a priori all the consequences which are actually given. If for that purpose supplementary hypotheses have to be called in, the force of the main assumption is proportionately weakened. Thus we can easily explain natural order and design, if we are allowed to postulate a Divine Author who is absolutely perfect and all-powerful. But that hypothesis lies open to all the objections suggested by defects and evils in nature, and can only be preserved through new hypotheses which modify the main assumption. Similarly the hypothesis of the human soul as an abiding and purely spiritual being, existing in independence of the body, has to be modified to meet the difficulties which arise from the phenomena of growth and decay. But the new hypotheses, then constructed, derive their whole authority from the main hypothesis which they are themselves defending.
Such is Kant’s criticism of metaphysics when its teaching is based on the facts of experience hypothetically interpreted. In regard to transcendent metaphysics, there are, in Kant’s view, only two alternatives.[1644] Either its propositions must be established independently of all experience in purely a priori fashion, and therefore as absolutely certain; or they must consist in hypotheses empirically grounded. The first alternative has in the Analytic and Dialectic been shown to be impossible; the second alternative he rejects for the above reasons.