acting, constitute only the diversity of substances; we distinguish one
being from another but by the diversity of the impressions or movements
which they communicate to our organs.




XL.--CONTINUATION.

You see that everything in nature is in a state of activity, and you
pretend that nature of itself is dead and without energy! You believe
that all this, acting of itself, has need of a motor! Well! who is this
motor? It is a spirit, that is to say, an absolutely incomprehensible
and contradictory being. Conclude then, I say to you, that matter acts
of itself, and cease to reason about your spiritual motor, which has
nothing that is necessary to put it into motion. Return from your
useless excursions; come down from an imaginary into a real world; take
hold of second causes; leave to theologians their "First Cause," of
which nature has no need in order to produce all the effects which you
see.




XLI.--OTHER PROOFS THAT MOTION IS IN THE ESSENCE OF MATTER, AND THAT IT
IS NOT NECESSARY TO SUPPOSE A SPIRITUAL MOTOR.

It is but by the diversity of impressions or of effects which substances
or bodies make upon us, that we feel them, that we have perceptions and
ideas of them, that we distinguish them one from another, that we assign