The existence, then, of matter is a fact: the existence of motion is another fact. Our visual organs point out to us matter with different essences, forming a variety of combinations, endowed with various properties that discriminate them. Indeed, it is a palpable error to believe that matter is a homogeneous body, of which the parts differ from each other only by their various modifications. Among the individuals of the same species that come under our notice, no two resemble exactly; and it is therefore evident that the difference of situation alone will, necessarily, carry a diversity more or less sensible, not only in the modifications, but also in the essence, in the properties, in the entire system of beings. This truth was well understood by the profound and subtle LEIBNITZ.
If this principle be properly digested, and experience seems always to produce evidence of its truth, we must be convinced that the matter or primitive elements which enter into the composition of bodies, are not of the same nature, and consequently, can neither have the same properties, nor the same modifications; and if so, they cannot have the same mode of moving and acting. Their activity or motion, already different, can be diversified to infinity, augmented or diminished, accelerated or retarded, according to the combinations, the proportions, the pressure, the density, the volume of the matter, that enters their composition. The endless variety to be produced, will need no further illustration than the commonest book of arithmetic furnishes us, where it will be found, that to ring all the changes that can be produced on twelve bells only, would occupy a space of more than ninety-one years. The element of fire is visibly more active and more inconstant than that of earth. This is more solid and ponderous than fire, air, or water. According to the quantity of these elements, which enter the composition of bodies, these must act diversely, and their motion must in some measure partake the motion peculiar to each of their constituent parts. Elementary fire appears to be in Nature the principle of activity; it may be compared to a fruitful leaven, that puts the mass into fermentation and gives it life. Earth appears to be the principle of solidity in bodies, from its impenetrability, and by the firm coherence of its parts. Water is a medium, to facilitate the combination of bodies, into which it enters itself, as a constituent part. Air is a fluid whose business it seems to be, to furnish the other elements with the space requisite to expand, to exercise their motion, and which is, moreover, found proper to combine with them. These elements, which our senses never discover in a pure state—which are continually and reciprocally set in motion by each other—which are always acting and re-acting, combining and separating, attracting and repelling—are sufficient to explain to us the formation of all the beings we behold. Their motion is uninterruptedly and reciprocally produced from each other; they are alternately causes and effects. Thus, they form a vast circle of generation and destruction—of combination and decomposition, which, it is quite reasonable to suppose, could never have had a beginning, and which, consequently can never have an end. In short, Nature is but an immense chain of causes and effects, which unceasingly flow from each other. The motion of particular beings depends on the general motion, which is itself maintained by individual motion. This is strengthened or weakened, accelerated or retarded, simplified or complicated, procreated or destroyed, by a variety of combinations and circumstances, which every moment change the directions, the tendency, the modes of existing, and of acting, of the different beings that receive its impulse.
If it were true, as has been asserted by some philosophers, that every thing has a tendency to form one unique or single mass, and in that unique mass the instant should arrive when all was in nisus, all would eternally remain in this state; to all eternity there would be no more than one Being and one effort: this would be eternal and universal death.
If we desire to go beyond this, to find the principle of action in matter, to trace the origin of things, it is for ever to fall back upon difficulties; it is absolutely to abridge the evidence of our senses; by which only we can understand, by which alone we can judge of the causes acting upon them, or the impulse by which they are set in action.
Let us, therefore, content ourselves with saying WHAT is supported by our experience, and by all the evidence we are capable of understanding; against the truth of which not a shadow of proof, such as our reason can admit, has ever been adduced—which has been maintained by philosophers in every age—which theologians themselves have not denied, but which many of them have upheld; namely, that matter always existed; that it moves by virtue of its essence; that all the phenomena of Nature is ascribable to the diversified motion of the variety of matter she contains; and which, like the phoenix, is continually regenerating out of its own ashes.
CHAP. III.
Of Matter.—Of its various Combinations.—Of its diversified Motion, or of the Course of Nature.
We know nothing of the elements of bodies, but we know some of their properties or qualities; and we distinguish their various matter by the effect or change produced on our senses; that is to say, by the variety of motion their presence excites in us. In consequence, we discover in them, extent, mobility, divisibility, solidity, gravity, and inert force. From these general and primitive properties flow a number of others, such as density, figure, colour, ponderosity, &c. Thus, relatively to us, matter is all that affects our senses in any manner whatever; the various properties we attribute to matter, by which we discriminate its diversity, are founded on the different impressions we receive on the changes they produce in us.