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 incarnate. For
sense is to knowledge what conscience is to reasoning about light 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 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 to the vast majority of mankind--of all that is supported by
demonstration. For the power to prove implies a sense of the need of
proof, and things which the majority of mankind find practically
important are in ninety-nine cases out of a hundred above proof. The
need of proof becomes as obsolete in the case of assured knowledge, as
the practice of fortifying towns in the middle of an old and long-settled
country. Who builds defences for that which is impregnable or little
likely to be assailed? The answer is ready, that unless the defences had
been built in former times it would be impossible to do without them now;
but this does not touch the argument, which is not that demonstration is
unwise but that as long as a demonstration is still felt necessary, and
therefore kept ready to hand, the subject of such demonstration is not
yet securely known. _Qui s'excuse_, _s'accuse_; and unless a matter can
hold its own without the brag and self-assertion of continual
demonstration, it is still more or less of a parvenu, which we shall not
lose much by neglecting till it has less occasion to blow its own
trumpet. The only alternative is that it is an error in process of
detection, for if evidence concerning any opinion has long been deemed
superfluous, and ever after this comes to be