It is clear, then, that the continual motion inherent in matter, changes and destroys all beings; every instant depriving them of some of their properties, to substitute others: it is motion, which, in thus changing their actual essence, changes also their order, their direction, their tendency, and the laws which regulate their mode of acting and being: from the stone formed in the bowels of the earth, by the intimate combination and close coherence of similar and analogous particles, to the sun, that vast reservoir of igneous particles, which sheds torrents of light over the firmament; from the benumbed oyster, to the thoughtful and active man; we see an uninterrupted progression, a perpetual chain of motion and combination; from which is produced, beings that only differ from each other by the variety of their elementary matter--by the numerous combinations of these elements, from whence springs modes of action and existence, diversified to infinity. In generation, in nutrition, in preservation, we see nothing more than matter, variously combined, of which each has its peculiar motion, regulated by fixed and determinate laws, which oblige them to submit to necessary changes. We shall find, in the formation, in the growth, in the instantaneous life, of animals, vegetables, and minerals, nothing but matter; which combining, accumulating, aggregating, and expanding by degrees, forms beings, who are either feeling, living, vegetating, or else destitute of these faculties; which, having existed some time under one particular form, are obliged to contribute by their ruin to the production of other forms. Thus, to speak strictly, nothing in Nature is either born, or dies, according to the common acceptation of those terms. This truth was felt by many of the ancient philosophers. PLATO says, that according to tradition, "the living were born of the dead, the same as the dead did come of the living; and that this is the constant routine of Nature." He adds from himself, "who knows, if to live, be not to die; and if to die, be not to live?" This was the doctrine of PYTHAGORAS, a man of great talent and no less note. EMPEDOCLES asserts, "there is neither birth nor death, for any mortal; but only a combination, and a separation of that which was combined, and that this is what amongst men they call birth, and death." Again he remarks, "those are infants, or short-sighted persons, with very contracted understandings, who imagine any thing is born, which did not exist before, or that any thing can die or perish totally." CHAP. IV. _Laws of Motion, common to every Being of Nature.--Attraction and Repulsion.--Inert Force.--Necessity._