Page:The System of Nature.djvu/52

 motion was the consequence of its existence, of its essence, of its properties: its different modes of action would be the necessary consequence of its different modes of being. Matter without properties would be a mere nothing; therefore, as soon as matter exists, it must act; as soon as it is various, it must act variously; if it cannot commence to exist, it must have existed from all eternity; if it has always existed, it can never cease to be: if it can never cease to be, it can never cease to act by its own energy. Motion is a manner of being, which matter derives from its peculiar existence.

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;