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 from the association of ideas, according to my hypothesis.

It is universally allowed by the writers on optics, that the eye at all
times sees an equal number of physical points, and that a man on the top
of a mountain has no larger an image presented to his senses, than
when he is cooped up in the narrowest court or chamber. It is only by
experience that he infers the greatness of the object from some peculiar
qualities of the image; and this inference of the judgment he confounds
with sensation, as is common on other occasions. Now it is evident,
that the inferenc