Motion, alternately communicated and received, establishes the connection or relation between the different orders of beings: when they are in the sphere of reciprocal action, attraction approximates them; repulsion dissolves and separates them; the one strengthens and preserves them; the other enfeebles and destroys them. Once combined, they have a tendency to conserve themselves in that mode of existence, by virtue of their _inert force_; in this they cannot succeed, because they are exposed to the continual influence of all other beings, who perpetually and successively act upon them; their change of form, their dissolution, is requisite to the preservation of Nature herself: this is the sole end we are able to assign her--to which we see her tend without intermission--which she follows without interruption, by the destruction and reproduction of all subordinate beings, who are obliged to submit to her laws--to concur, by their mode of action, to the maintenance of her active existence, so essentially requisite to the GREAT WHOLE. It is thus each being is an individual, who, in the great family, performs his necessary portion of the general labour--who executes the unavoidable task assigned to him. All bodies act according to laws, inherent in their peculiar essence, without the capability to swerve, even for a single instant, from those according to which Nature herself acts. This is the central power, to which all other powers, essences, and energies, are submitted: she regulates the motions of beings, by the necessity of her own peculiar essence: she makes them concur by various modes to the general plan: this appears to be nothing more than the life, action, and maintenance of the whole, by the continual change of its parts. This object she obtains, in removing them, one by the other; by that which establishes, and by that which destroys, the relation subsisting between them; by that which gives them, and that which deprives them of, their forms, combinations, proportions, and qualities, according to which they act for a time, after a given mode; these are afterwards taken from them, to make them act after a different manner. It is thus that Nature makes them expand and change, grow and decline, augment and diminish, approximate and remove, forms and destroys them, according as she finds it requisite to maintain the whole; towards the conservation which this Nature is herself essentially necessitated to have a tendency.