Chapter LVII: Section IV: 1707

THE DISCIPLINE OF PURE REASON IN REGARD TO ITS PROOFS[1708]

This section merely restates the general nature and requirements of transcendental proof. The exposition is much less satisfactory than that already given in the _Analytic_ and _Dialectic_. The only really new factor is the distinction between apagogical and direct proof. The former may produce conviction, but cannot enable us to comprehend the grounds of the truth of our conviction. Also, outside mathematics, it is extremely dangerous to attempt to establish a thesis by showing its contradictory to be impossible.[1709] This is especially true in the sphere of our Critical enquiries, since the chief danger to be guarded against is the confounding of the subjectively necessary with the independently real. In this field of investigation it is never permissible to attempt to justify a synthetic proposition by refuting its opposite. Such seeming proofs can easily be secured, and have been the favourite weapons of dogmatic thinkers.

“Each must defend his position directly, by a legitimate proof that
carries with it transcendental deduction of the grounds upon which
it is itself made to rest. Only when this has been done, are we in
a position to decide how far its claims allow of rational
justification. If an opponent relies on subjective grounds, it is
an easy matter to refute him. The dogmatist cannot, however, profit
by this advantage. His own judgments are, as a rule, no less
dependent upon subjective influences; and he can himself in turn be
similarly cornered. But if both parties proceed by the direct
method, _either_ they will soon discover the difficulty, nay, the
impossibility, of showing reason for their assertions, and will be
left with no resort save to appeal to some form of prescriptive
authority; _or_ the _Critique_ will the more easily discover the
illusion to which their dogmatic procedure is due; and pure Reason
will be compelled to relinquish its exaggerated pretensions in the
realm of speculation, and to withdraw within the limits of its
proper territory--that of practical principles.”[1710]