ibution was the
invention of what he called the 'critical' philosophy, which, assuming
as a datum that there is knowledge of various kinds, inquired how such
knowledge comes to be possible, and deduced, from the answer to this
inquiry, many metaphysical results as to the nature of the world.
Whether these results were valid may well be doubted. But Kant
undoubtedly deserves credit for two things: first, for having perceived
that we have _a priori_ knowledge which is not purely 'analytic', i.e.
such that the opposite would be self-contradictory, and secondly,
for having made evident the philosophical importance of the theory of
knowledge.

Before the time of Kant, it was generally held that whatever knowledge
was _a priori_ must be 'analytic'. What this word means will be best
illustrated by examples. If I say, 'A bald man is a man', 'A plane
figure is a figure', 'A bad poet is a poet', I make a purely analytic
judgement: the subject spoken about is given as having at least two
properties, of which one is singled out to be asserted of it. Such
propositions as the above are trivial, and would never be enunciated
in real life except by an orator preparing the way for a piece of
sophistry. They are called 'analytic' because the predicate is obtained
by merely analysing the subject. Before the time of Kant it was thought
that all judgements of which we could be certain _a priori_ were of this
kind: that in all of them there was a predicate which was only part
of the subject of which it was asserted. If this were so, we should be
involved in a definite contradiction if we attempted to deny anything
that could be known _a priori_. 'A bald man is not bald' would assert
and deny baldness of the same man, and would therefore contradict
itself. Thus according to the philosophers before Kant, the law of
contradiction, which asserts that nothing can at the same time have and
not have a certain property, sufficed to establish the truth of all _a
priori_ knowledge.

Hume (1711-76), who preceded Kant, accepting the usual view as to what
makes knowledge _a priori_, discovered that, in many cases which had
previously been supposed analytic, and notably in the case of cause and
effect, the connexion was really synthetic. Before Hume, rationalists at
least had supposed that the effect could be logically deduced from the
cause, if only we had sufficient knowledge. Hume argued--correctly, as
would now be generally admitted--that this could