s its
own creation, or, because in adopting it, it seems to the mind that it
should have itself discovered the hypothesis, so much does the latter
harmonize with its inner states. Let us take the hypothesis of
evolution, for example: we need not mention its high philosophical
bearing, and the immense influence that it exerts on almost all forms of
human thought. Nevertheless, it still remains an hypothesis; but for
many it is an indisputable and inviolable dogma, raised far above all
controversy. They accept it with the uncompromising fervor of believers:
a new proof of the underlying connection between imagination and
belief--they increase and decrease _pari passu_.

III

Should we assign as belonging solely to the imagination every invention
or discovery--in a word, whatever is new--in the well-organized sciences
that form a body of solid, constantly-broadening doctrine? It is a hard
question. That which raises scientific knowledge above popular knowledge
is the use of an experimental method and rigorous reasoning processes;
but, is not induction and deduction going from the known to the unknown?
Without desiring to depreciate the method and its value, it must
nevertheless be admitted that it is preventive, not inventive. It
resembles, says Condillac, the parapets of a bridge, which do not help
the traveler to walk, but keep him from falling over. It is of value
especially as a habit of mind. People have wisely discoursed on the
"methods" of invention. There are none; but for which fact we could
manufacture inventors just as we make mechanics and watchmakers. It is
the imagination that invents, that provides the rational faculties with
their materials, with the position, and even the solution of their
problems. Reasoning is only a means for control and proof; it transforms
the work of the imagination into acceptable, logical results. If one has
not imagined beforehand, the logical method is aimless and useless, for
we cannot reason concerning the completely unknown. Even when a problem
seems to advance towards solution wholly through the reason, the
imagination ceaselessly intervenes in the form of a succession of
groupings, trials, guesses, and possibilities that it proposes. The
function of method is to determine its value, to accept or reject
it.[111]

Let us show by a few examples that conjecture, the work of the combining
imagination, is at the root of the most diverse scientific
inventions.[112]

Every m