Unformatted text preview: hem for oneself, in one’s own thinking; then one can find them elsewhere,
where one would certainly not have found them before because the authors were not clear
in their own minds about what they were saying. ·That is how I found t he 14
analytic/synthetic distinction in Locke’s pages when Hume did not find it there: the crucial
point is that I had first worked out the distinction for myself·.
Section 4: The general problem of the Prolegomena: is metaphysics possible at all?
If we had a real metaphysics that could claim to be a science - if we could say ‘Here is
metaphysics, all you have to do is to learn it, and it will convince you of its truth’ - then
we would not have to ask whether metaphysics is possible, ·just as we don’t have to ask
whether geometry, say, is possible·. Our only question would concern how it is possible,
and how reason should set about doing metaphysics; and this would be Ÿa test of our
mental skills, not Ÿa challenge to the existence of the thing itself.
However, things haven’t turned out so well for human reason. There is no single
book that one can point to, as one might hold up a Euclid, and say, ‘This is metaphysics;
here you will find knowledge of a highest being and of a future world, which is the noblest
aim of this science, proved from principles of pure reason.’ Many propositions have been
agreed without dispute to be necessary and certain, but they are all analytic, and concern
the materials and building-stones of metaphysics rather than the enlargement of our
knowledge. You may point to some synthetic propositions (e.g. the law of sufficient
reason) which are widely accepted, though you have never proved them through mere
reason, a priori, as you ought to have. Help yourself to them; but when you want to use
them for some serious purpose you will find yourself caught up in wrong or dubious
assertions - the sort of thing that has set metaphysical systems against one another in their
doctrines or in their arguments, destroying their claims to be believed.
Indeed, the very attempts to create a science of metaphysics were the first cause of
early scepticism - a way of thinking in which reason attacks itself so violently that it could
never have arisen except in complete despair about our ability to carry out reason’s most
important designs. Men began to investigate reason itself long before starting methodically
to investigate nature ·in the physical sciences·. Even at that stage, reason had already been
employed in connection with ordinary experience; and reason is always present to us,
whereas laws of nature have to be laboriously sought out. So metaphysics floated to the
top like foam, which dissolved the moment it was scooped off. But as soon as one lot of
foam dissolved, more came frothing up to the surface. Some philosophers eagerly
collected foam; some tried to show their wisdom by ridiculing the vain efforts of others;
none looked for the cause of the foam down in the depths.
We are tired of dogmatism that teaches us nothing, and just as tired of scepticism
that promises us nothing (not even permission to rest comfortably in ignorance). The
knowledge we need is important, and that is a challenge to us; but we have had centuries
of bad experience with things we thought we knew through ‘pure reason’ that turned out
not to be knowledge at all, and that makes us suspicious. ·So we are Ÿunder pressure to
push on forwards, and also Ÿnervous about doing so·. Where do we go from here? That
depends on the answer to the question ‘Is metaphysics possible at all?’ We should try to
answer this not by picking away sceptically at particular doctrines of this or that actual
system of metaphysics - for we don’t yet admit that there are any systems of metaphysics but by considering the concept of such a science.
In the Critique of Pure Reason I tackled this problem by looking into pure reason
itself: by establishing the nature of reason, I was able to work out what its materials and 15
methods must be. This is hard to do. It demands a reader who is resolved to think himself
gradually into a system based on reason itself and on nothing else, aiming to develop
knowledge out of that alone, without help from any fact. Because the present work is
called Preliminaries, on the other hand, it ought to consist of preliminary exercises; they
should aim not to Ÿexpound the science itself but rather to Ÿshow what is needed for the
science to be brought into existence. Preliminaries should try to get help from something
that is already known to be reliable, from which one can confidently work back to the
ultimate sources that are not yet known.
Although we can’t take it for granted that there is any such science as metaphysics,
we can - fortunately - say with confidence that some pure synthetic a priori knowledge is
real and that we already have it. I refer to pure mathematics and pure natural science.
Each of these contains propositions that are everywhere recognized - partly through
reason that shows them to be necessary and certain, and partly through universal
agreement arising from experience (though not actually based on experience). So we have
some a p...
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