Thus we have fully exhibited metaphysics according to its subjective necessity, as it is really given in the natural dispositionof the human Reason, and indeed in what constitutes its essential purpose. We have found in the course of this investigation, that such a merelynatural use of such a disposition of our Reason involves us in extravagant dialectical conclusions, partly apparently, and partly really, conflicting [with one another], if no discipline bridles it and keeps it within limits, which is only possible by means of scientific criticism. And, in addition, [we have found] this falla- cious metaphysics to be dispensable to the promotion of the knowledge of Nature, and even prejudicial to it. It always remains, notwithstanding, a task worthy of research, to find out the natural endsaimed at by this disposition in our Reason to transcendent conceptions, since everything in Nature must have been originally designed for some useful purpose.
Such an investigation is here out of place; I confess, moreover, that all I here say respecting the primary ends of Nature is only conjecture, but which may be permitted me in this case, as the question does not concern the objective validity of metaphysical judgments, but refers merely to the natural disposition to the latter, and thus lies outside the system of metaphysics, in that of anthropology.
When I compare all transcendental ideas whose content constitutes the special problem of the natural, pure Reason, compelling it to leave the mere contemplation of Nature and to pass beyond all possible experience, and in this endeav- our to produce the thing (be it knowledge or nonsense) called metaphysics, I believe myself to have discovered that this natural disposition is intended to free our conceptions from the chains of experience and the limits of the mere con- templation of Nature, in so far that it may at least see a field opened before it, containing mere objects for pure Reason, which cannot be arrived at by any sensibility. The purpose is not, indeed, to occupy ourselves speculatively with these objects, (because we can find no firm ground for our feet), but because practical principles, without finding such a space before them for their necessary expectation and hope, could not expand themselves to the universality, Reason indis- pensably requires, from a moral point of view.
Now, I find that the psychologicalidea, however little may be the insight I obtain by its means into the pure nature of the human soul, which is raised above all
conceptions of experience, at least sufficiently shows me the inadequacy of the latter, and thereby preserves me from materialism as being a psychological conception of no avail for the expla-
nation of Nature, and besides, as narrowing Reason in its practical aspect. In the same way the cosmological ideas, by the obvious inadequacy of all possible knowledge of Nature
to satisfy Reason in its justifiable inquiries, serve to keep us from the Naturalism which proclaims Nature for self-sufficing. Finally, as all natural necessity in the sense-world is
invariably conditioned, inasmuch as it always presupposes dependence of things on one another, and, as unconditioned necessity must be sought for in the unity of a Cause separate from the
sense-world, (but the causality of which, if it were mere Nature, could yet never render comprehensible the existence of the contingent as its consequence;) [this being so,] Reason frees itself
by means of the theologicalideafrom fatalism, as well from that of a blind natural necessity in the coherence of Nature, without a first principle, as in the
causality of this principle itself, and leads to the conception of a cause through freedom, in other words, a supreme intelligence. Thus the transcendental ideas serve, if not to instruct us
positively, at least to do away with the audacious assertions of materialism, naturalism, and fatalism, which narrow the field of
Reason, and thereby to procure a place for moral ideas outside the region of speculation; and this, as it seems to me, will in some measure explain the above natural disposition.
The practical utility a merely speculative science may have, lies outside the boundaries of this science, and hence can be merely viewed as a scholium, and, like all scholia, not as forming a part of the science itself. At the same time, this reference lies at least within the boundaries of philosophy, especially of that which draws from the sources of pure Rea- son, where the speculative use of Reason in metaphysics must have a necessary unity with its practical use in morals. Hence the unavoidable dialectic of pure Reason in metaphysics must be considered as natural disposition—not mere- ly as an illusion requiring to be resolved, but as a natural institution, as concerns its end—deserving, if possible, to be explained, although this task, being supererogatory, cannot in justice be claimed of metaphysics proper. …
And thus I conclude the analytical solution of the problem I had myself proposed—Howismetaphysicsatallpossible?having proceeded from that in which its use is really given, at least in its consequences, to the grounds of its possibility.
- Kant insists on the thinkability—though not on the actuality—of God, of the soul, and of causality through freedom. Is he entitled to this? Think back to the limitations Kant imposed on the use of the Categories earlier in the Prolegomena.