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complex, the intelligible world,* are nothing but representation of a problem, of
which the object in itself is possible but the solution, from the nature of our under-
standing, totally impossible. For our understanding is not a faculty of intuition, but of
the connection of given intuitions in one experience. Experience must therefore con-
tain all the objects for our concepts; but beyond it no concepts have any significance,
as there is no intuition that might offer them a foundation.
§ 35. The imagination may perhaps be forgiven for occasional vagaries and for
not keeping carefully within the limits of experience, since it gains life and vigor by
such flights and since it is always easier to moderate its boldness than to stimulate its
languor. But the understanding which ought to thinkcan never be forgiven for indulging
in vagaries; for we depend upon it alone for assistance to set bounds, when necessary, to
the vagaries of the imagination.
But the understanding begins its aberrations very innocently and modestly. It first
brings to light the elementary cognitions which inhere in it prior to all experience, but
which yet must always have their application in experience. It gradually drops these
limits—and what is there to prevent it, as it has quite freely derived its principles from
itself? It then proceeds first to newly imagined powers in nature, then to beings outside
nature—in short, to a world for whose construction the materials cannot be wanting,
because fertile fiction furnishes them abundantly, and though not confirmed it is never
refuted by experience. This is the reason that young thinkers are so partial to meta-
physics constructed in a truly dogmatic manner, and often sacrifice to it their time and
their talents, which might be otherwise better employed.
But there is no use in trying to moderate these fruitless endeavors of pure reason by
all manner of cautions as to the difficulties of solving questions so occult, by complaints
of the limits of our reason, and by degrading our assertions into mere conjectures. For if
their impossibility is not distinctly shown, and reason’s knowledge of itself does not
become a true science, in which the field of its right use is distinguished, so to say, with
geometrical certainty from that of its worthless and idle use, these fruitless efforts will
never be wholly abandoned.
§ 36. How is nature itself possible? This question—the highest point that tran-
scendental philosophy can ever reach, and to which, as its boundary and completion, it
must proceed—really contains two questions.
First:How is nature in the material sense, that is, as to intuition, or considered as
the totality of appearances, possible; how are space, time, and that which fills both—the
object of sensation—possible generally? The answer is: By means of the constitution of
our sensibility, according to which it is in its own way affected by objects which are in
themselves unknown to it and totally distinct from those appearances. This answer is
given in the Critiqueitself in the “Transcendental Aesthetic,” and in these Prolegomena
by the solution of the first general problem.
Secondly:How is nature possible in the formal sense, as the totality of the rules under
which all appearances must come in order to be thought as connected in experience? The
answer must be this: It is only possible by means of the constitution of our understanding,
according to which all the above representations of the sensibility are necessarily referred to
317*We speak of the “intelligible world,” not (as the usual expression is) “intellectual world.” For cogni-
tions are intellectual through the understanding and refer to our world of sense also; but objects, in so far as
they can be represented merely by the understanding, and to which none of our sensible intuitions can refer,
are termed “intelligible.” But as some possible intuition must correspond to every object, we would have to
assume an understanding that intuits things immediately; but of such we have not the least notion, nor have
we any notion of the beings of the understandingto which it should be applied.
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