r thing; but in reality we are obliged to consider problems
one by one, in terms which are, for that very reason, provisional, so
that the solution of each problem will have to be corrected
indefinitely by the solution that will be given to the problems that
will follow: thus, science as a whole is relative to the particular
order in which the problems happen to have been put. It is in this
meaning, and to this degree, that science must be regarded as
conventional. But it is a conventionality of fact so to speak, and not
of right. In principle, positive science bears on reality itself,
provided it does not overstep the limits of its own domain, which is
inert matter.

Scientific knowledge, thus regarded, rises to a higher plane. In return,
the theory of knowledge becomes an infinitely difficult enterprise, and
which passes the powers of the intellect alone. It is not enough to
determine, by careful analysis, the categories of thought; we must
engender them. As regards space, we must, by an effort of mind _sui
generis_, follow the progression or rather the regression of the
extra-spatial degrading itself into spatiality. When we make ourselves
self-conscious in the highest possible degree and then let ourselves
fall back little by little, we get the feeling of extension: we have an
extension of the self into recollections that are fixed and external to
one another, in place of the tension it possessed as an indivisible
active will. But this is only a beginning. Our consciousness, sketching
the movement, shows us its direction and reveals to us the possibility
of continuing it to the end; but consciousness itself does not go so
far. Now, on the other hand, if we consider matter, which seems to us at
first coincident with space, we find that the more our attention is
fixed on it, the more the parts which we said were laid side by side
enter into each other, each of them undergoing the action of the whole,
which is consequently somehow present in it. Thus, although matter
stretches itself out in the direction of space, it does not completely
attain it; whence we may conclude that it only carries very much
further the movement that consciousness is able to sketch within us in
its nascent state. We hold, therefore, the two ends of the chain, though
we do not succeed in seizing the intermediate links. Will they always
escape us? We must remember that philosophy, as we define it, has not
yet become completely conscious of itsel