that the conclusion, which we draw from a present object to its absent
cause or effect, is never founded on any qualities, which we observe in
that object, considered in itself, or, in other words, that it is
impossible to determine, otherwise than by experience, what will result
from any phenomenon, or what has preceded it. But though this be so evident
in itself, that it seemed not to require any, proof; yet some
philosophers have imagined that there is an apparent cause for the
communication of motion, and that a reasonable man might immediately
infer the motion of one body from the impulse of another, without having
recourse to any past observation. That this opinion is false will admit
of an easy proof. For if such an inference may be drawn merely from the
ideas of body, of motion, and of impulse, it must amount to a
demonstration, and must imply the absolute impossibility of any contrary
supposition. Every effect, then, beside the communication of motion,
implies a formal contradiction; and it is impossible not only that it can
exist, but also that it can be conceived. But we may soon satisfy
ourselves of the contrary, by forming a clear and consistent idea of one
body's moving upon another, and of its rest immediately upon the contact,
or of its returning back in the same line in which it came; or of its
annihilation; or circular or elliptical motion: and in short, of an
infinite number of other changes, which we may suppose it to undergo.
These suppositions are all consistent and natural; and the reason, Why we
imagine the communication of motion to be more consistent and natural not
only than those suppositions, but also than any other natural effect, is
founded on the relation of resemblance betwixt the cause and effect,
which is here united to experience, and binds the objects in the closest
and most intimate manner to each other, so as to make us imagine them to
be absolutely inseparable. Resemblance, then, has the same or a parallel
influence with experience; and as the only immediate effect of experience
is to associate our ideas together, it follows, that all belief arises