eality
under an arrested form. In order to think movement, a constantly renewed
effort of the mind is necessary. Signs are made to dispense us with this
effort by substituting, for the moving continuity of things, an
artificial reconstruction which is its equivalent in practice and has
the advantage of being easily handled. But let us leave aside the means
and consider only the end. What is the essential object of science? It
is to enlarge our influence over things. Science may be speculative in
its form, disinterested in its immediate ends; in other words we may
give it as long a credit as it wants. But, however long the day of
reckoning may be put off, some time or other the payment must be made.
It is always then, in short, practical utility that science has in view.
Even when it launches into theory, it is bound to adapt its behavior to
the general form of practice. However high it may rise, it must be ready
to fall back into the field of action, and at once to get on its feet.
This would not be possible for it, if its rhythm differed absolutely
from that of action itself. Now action, we have said, proceeds by leaps.
To act is to re-adapt oneself. To know, that is to say, to foresee in
order to act, is then to go from situation to situation, from
arrangement to rearrangement. Science may consider rearrangements that
come closer and closer to each other; it may thus increase the number of
moments that it isolates, but it always isolates moments. As to what
happens in the interval between the moments, science is no more
concerned with that than are our common intelligence, our senses and our
language: it does not bear on the interval, but only on the extremities.
So the cinematographical method forces itself upon our science, as it
did already on that of the ancients.

Wherein, then, is the difference between the two sciences? We indicated
it when we said that the ancients reduced the physical order to the
vital order, that is to say, laws to genera, while the moderns try to
resolve genera into laws. But we have to look at it in another aspect,
which, moreover, is only a transposition, of the first. Wherein consists
the difference of attitude of the two sciences toward change? We may
formulate it by saying that _ancient science thinks it knows its object
sufficiently when it has noted of it some privileged moments, whereas
modern science considers the object at any moment whatever_.

The forms or ideas of Plato or of