It is thus that the human mind acquires knowledge. How then does
hypothesis come to be made light of? How can it be seriously said that
we have excluded hypothesis from the sphere of science, whereas the
moment the faculty of supposing should cease to be in exercise, the
march of science would be arrested; since, except a small number of
principles the evidence of which is immediate, all the truths we
possess are only suppositions confirmed by experiment? The reason is
here: Our mind forms a thousand different suppositions at its own will
and fancy; and it shrinks from that studious toil which alone puts it in
a position to make fruitful suppositions. We are for ever tempted to be
guessing, instead of setting ourselves, by patient observations, on the
road to real discoveries. It is therefore with good reason that theories
hastily built up have been condemned, and Lord Chancellor Bacon was
right in thinking that the human mind requires lead to be attached to
it, and not wings. Hence the inference has been drawn that the simplest
plan would be to cut the wings of thought, without reflecting that
thenceforward it would continue motionless. Because some had abused
hypothesis, others must conclude that we could do without it altogether.

Trivial and premature suppositions have therefore discredited
hypothesis, by encumbering science with a crowd of vain imaginations;
but this encumbrance would have been of small importance but for the
obstinacy with which false theories have too often been maintained
against the evidence of facts. If Ampère had found his experiment fail,
and had still continued to maintain his statements, he would not have
given proof of a happy audacity, but of a ridiculous obstinacy. Genius
itself makes mistakes, and experience alone distinguishes real laws from
mere freaks of our thought. We have maintained the rights of reason in
the spontaneous exercise of the faculty of discovery; but let us beware
how we ignore the rights of experience. It alone prepares discoveries;