as a fact that the greatest men are they who are most uncertain in
spite of certainty, and at the same time most certain in spite of
uncertainty, and who are thus best able to feel that there is nothing
in such complete harmony with itself as a flat contradiction in
terms. For nature hates that any principle should breed, so to
speak, hermaphroditically, but will give to each an help meet for it
which shall cross it and be the undoing of it; as in the case of
descent with modification, of which the essence would appear to be
that every offspring should resemble its parents, and yet, at the
same time, that no offspring should resemble its parents. But for
the slightly irritating stimulant of this perpetual crossing, we
should pass our lives unconsciously as though in slumber.

Until we have got to understand that though black is not white, yet
it may be whiter than white itself (and any painter will readily
paint that which shall show obviously as black, yet it shall be
whiter than that which shall show no less obviously as white), we may
be good logicians, but we are still poor reasoners. Knowledge is in
an inchoate state as long as it is capable of logical treatment; it
must be transmuted into that sense or instinct which rises altogether
above the sphere in which words can have being at all, otherwise it
is not yet vital. For sense is to knowledge what conscience is to
reasoning about right and wrong; the reasoning must be so rapid as to
defy conscious reference to first principles, and even at times to be
apparently subversive of them altogether, or the action will halt.
It must, in fact, become automatic before we are safe with it. While
we are fumbling for the grounds of our conviction, our conviction is
prone to fall, as Peter for lack of faith sinking into the waves of
Galilee; so that the very power to prove at all is an a priori
argument against the truth--or at any rate the practical importance