In order, however, to connect my defense with the interest of the philosophical
commonwealth, I propose a test, which must be decisive as to the mode whereby all
metaphysical investigations may be directed to their common purpose. This is nothing
more than what mathematicians have done in establishing the advantage of their methods
by competition. I challenge my critic to demonstrate, as is only just, on a priorigrounds,
in his own way, any single really metaphysical proposition asserted by him. Being meta-
physical, it must be synthetical and known a priorifrom concepts, but it may also be any
one of the most indispensable propositions, as, for instance, the principle of the persis-
tence of substance or of the necessary determination of events in the world by their
causes. If he cannot do this (silence however is confession), he must admit that, since
metaphysics without apodictic certainty of propositions of this kind is nothing at all, its
possibility or impossibility must before all things be established in a critique of pure rea-
son. Thus he is bound either to confess that my principles in the Critiqueare correct, or
he must prove their invalidity. But as I can already foresee that, confidently as he has
hitherto relied on the certainty of his principles, when it comes to a strict test he will not
find a single one in the whole range of metaphysics he can boldly bring forward, I will
concede to him an advantageous condition, which can only be expected in such a com-
petition, and will relieve him of the onus probandiby laying it on myself.
He finds in these Prolegomenaand in my Critique* eight propositions, of which
one in each pair contradicts the other, but each of which necessarily belongs to meta-
physics, by which it must either be accepted or rejected (although there is not one that
has not in its time been assumed by some philosopher). Now he has the liberty of select-
ing any one of these eight propositions at his pleasure and accepting it without any
proof, of which I shall make him a present, but only one (for waste of time will be just
as little serviceable to him as to me), and then of attacking my proof of the opposite
proposition. If I can save this one and at the same time show that, according to princi-
ples which every dogmatic metaphysics must necessarily recognize, the opposite of the
proposition adopted by him can be just as clearly proved, it is thereby established that
metaphysics has an hereditary failing not to be explained, much less set aside, until we
ascend to its birthplace, pure reason itself. And thus my Critiquemust either be
accepted or a better one take its place; at least it must be studied, which is the only thing
I now require. If, on the other hand, I cannot save my demonstration, then a synthetic
proposition a priorifrom dogmatic principles is to be reckoned to the score of my oppo-
nent, and I shall deem my impeachment of ordinary metaphysics unjust and pledge
myself to recognize his stricture on my Critiqueas justified (although this would not be
the consequence by a long way). To this end it would be necessary, it seems to me, that
he should step out of his incognito. Otherwise I do not see how it could be avoided that,
instead of dealing with one, I should be honored or besieged by several challenges com-
ing from anonymous and unqualified opponents.PROPOSALS AS TO ANINVESTIGATION OF THE“CRITIQUE”
UPONWHICH AJUDGMENTMAYFOLLOWI feel obliged to the learned public even for the silence with which it for a long time
honored my Critique,for this proves at least a postponement of judgment and some
supposition that, in a work leaving all beaten tracks and striking out on a new path, in848 IMMANUELKANT
380
*[The reference is to the theses and antitheses of the antinomies.—L.W.B.]379