Existence supposes properties in the thing that exists: whenever it has
properties, its mode of action must necessarily flow from those
properties which constitute, its mode of being. Thus, when a body is
ponderous, it must fall; when it falls, it must come in collision with
the bodies it meets in its descent; when it is dense, when it is solid,
it must, by reason of this density, communicate motion to the bodies
with which it clashes; when it has analogy, when it has affinity with
these bodies, it must be attracted, must be united with them; when it
has no point of analogy with them, it must be repulsed.

From which it may be fairly inferred, that in supposing, as we are under
the necessity of doing, the existence of matter, we must suppose it to
have some kind of properties; from which its motion, or modes of action,
must necessarily flow. To form the universe, DESCARTES asked but matter
and motion: a diversity of matter sufficed for him; variety of motion
was the consequence of its existence, of its essence, of its properties:
its different modes of action would be the necessary consequence of its
different modes of being. Matter without properties would be a mere
nothing; therefore, as soon as matter exists, it must act; as soon as it
is various, it must act variously; if it cannot commence to exist, it
must have existed from all eternity; if it has always existed, it can
never cease to be: if it can never cease to be, it can never cease to
act by its own energy. Motion is a manner of being, which matter derives
from its peculiar existence.

The existence, then, of matter is a fact: the existence of motion is
another fact. Our visual organs point out to us matter with different
essences, forming a variety of combinations, endowed with various
properties that discriminate them. Indeed, it is a palpable error to
believe that matter is a homogeneous body, of which the parts differ