im
study that nature, let him learn her laws, and contemplate the energy
and the unchanging fixity with which she acts; let him apply his
discoveries to his own felicity, and submit in silence to laws from
which nothing can withdraw him; let him consent to ignore the causes,
surrounded as they are for him by an impenetrable veil; let him undergo
without a murmur the decrees of universal force."

_Science derived from experience is the source of all wise action._ It
is physical science (_la physique_), and experience, that man ought to
consult in religion, morals, legislature, as well as in knowledge and
the arts. It is by our senses that we are bound to universal nature; it
is by our senses that we discover her secrets. The moment that we first
experience them we fall into a void where our imagination leads us
endlessly astray.

_Movement is what establishes relations between our organs and external
objects._ Every object has laws of movement that are peculiar to itself.
Everything in the universe is in movement; no part of nature is really
at rest.[151]

[151] Holbach confesses his obligation on this head to Toland's
_Letters to Serena_ (1704).

_Whence does nature receive this movement?_ From herself, since she is
the great whole, outside of which consequently nothing can exist. Motion
is a fashion of being which flows necessarily from the essence of
matter; matter moves by its own energy; its motion is due to forces
inherent in it; the variety of its movements, and of the phenomena
resulting from them, comes from variation of the properties, the
qualities, the combinations, originally found in the different primitive
matters of which nature is the assemblage.

_Whence came matter?_ Matter has existed from all eternity, and a motion
is one of the inherent and constitutive qualities of matter; motion also
has existed from eternity.

_The abstract idea of matter must be decomposed._ Instead of regarding
matter as a unique existence, rude, passive, incapable of moving itself,
of combining itself, we ought to look upon it as a Kind of existence, of
which the various individual members comprising the Kind, in spite of
their having some common properties, such as extension, divisibility,
figure, etc., still ought not to be ranged in a single class, nor
comprised in a single denomination.

_What is nature's process? Continual movement._ From the stone which is
formed in the bowels of the earth by the intimat