39. We are gravely and repeatedly told, that, _there is no effect
without a cause_; that, _the world did not make itself_. But the
universe is a cause, it is not an effect; it is not a work; it has
not been made, because it is impossible that it should have been made.
The world has always been; its existence is necessary; it is its own cause.
Nature, whose essence is visibly to act and produce, requires not, to
discharge her functions, an invisible mover, much more unknown than
herself. Matter moves by its own energy, by a necessary consequence
of its heterogeneity. The diversity of motion, or modes of mutual
action, constitutes alone the diversity of matter. We distinguish
beings from one another only by the different impressions or motions
which they communicate to our organs.


40. You see, that all is action in nature, and yet pretend that nature,
by itself, is dead and without power. You imagine, that this all,
essentially acting, needs a mover! What then is this mover? It is
a spirit; a being absolutely incomprehensible and contradictory.
Acknowledge then, that matter acts of itself, and cease to reason
of your spiritual mover, who has nothing that is requisite to put
it in action. Return from your useless excursions; enter again into
a real world; keep to _second causes_, and leave to divines their
_first cause_, of which nature has no need, to produce all the effects
you observe in the world.


41. It can be only by the diversity of impressions and effects, which
bodies make upon us, that we feel them; that we have perceptions and