MATTER., in physiology, whatever is extended and capable of making resist ance : hence, because all bodies, whether solid or fluid, are extended, and do re sist, we conclude that they are material, or made up of matter. That matter is one and the same thing in all bodies, and that all the variety we observe arises from the various forms and shapes it puts on, seems very probable, and may be concluded from a general observation of the procedure of nature in the generation and destruction of bodies. Thus, for in stance, water, rarified by heat, becomes vapour ; great collections of vapours form clouds ; these condensed descend in the form of hail or rain ; part of this collect ed on the earth constitutes rivers ; ano ther part mixing with the earth enters into the roots of plants, and supplies mat ter to, and expands itself into various spe cies of vegetables. In each vegetable it appears in one shape in the root, another in the stalk, another in the flowers, ano ther in the seeds, &c. From hence va rious bodies proceed ; from the oak, houses, ships, &c. from hemp and flax we have thread; from thence our various kinds of linen ; from thence garments ; these degenerate into rags, which receive from the mill the various forms of paper; hence our books.
According to Sir Isaac Newton, it Seems highly probable, that God in the beginning formed matter into solid, massy, impenetrable, moveable particles, or atoms, of such sizes and figures, and with such other properties, and in such proportion to space, as most conduced to the end for which he formed them ; and that these primitive particles, being so lids, are incomparably harder than any porous bodies compounded of them, even so hard as never to wear or break in pieces ; no ordinary power being able to divide what God himself made one in the first creation. While these particles continue entire, they may compose bo dies of one and the same nature and tex ture in all ages ; but should they wear away, or break in pieces, the nature of things depending on them may be chang ed. Water and earth, composed of old worn particles and fragments of parti cles, would not be of the same nature and texture now, with water and earth composed of entire particles in the be ginning; and therefore, that nature may be lasting, the changes of corporeal things are to he placed only in the va rious separations and new associations of motions of these permanent particles, compound bodies being apt to break, not in the midst of solid particles, but where these particles are Laid together, and only touch in a few points.
Dr. Berkeley argues against the ex istence of matter itself; and endeavours to prove that it is a mere .ens rationis, and has no existence out of the mind. Some late philosophers have advanced a new hypothesis concerning the nature and es sential properties of matter.
The first of these who suggested, or at least published an account of this hypo thesis, was M. Boscovich, in his " Theoria Philosophize Naturalis." He supposes, that matter is not impenetrable, but that it consists of physical points only, endued With powers of attraction and repulsion, taking place at different distances, that is, surrounded with various spheres of at traction and repulsion ; rn the same manner as solid matter is generally sup posed to be. I'rovided, therefore, that any body move with a sufficient degree of velocity, or have sufficient momen tum to overcome any power of repul sion that it may meet with, it will find no difficulty in making its way through any body whatever. If the velocity of such a body in motion be sufficiently great, P,oscovich contends, that the par ticles of any body through which it pass.
es, will not even be moved out of their place by it.
With a degree of velocity something less than this, they will be considerably agitated, and ignition might perhaps be the consequence, though the progress of the body in motion would not be sensi bly interrupted ; and with a still less mo mentum it might not pass at all. Mr.
Mitchell, Dr. Priestley, and some others of our own country, are of the same opi nion. See Priestley's " History of Dis coveries relating to Light," p. 390. In conformity to this hypothesis, this author maintains, that matter is not that inert substance that it has been supposed to be ; that powers of attraction or repul sion are necessary to its very being, and that no part of it appears to be impene trable to other parts. Accordingly, he defines matter to be a substance, possess ed of the property of extension, and of powers of attraction or repulsion, which are not distinct from matter, and foreign to it, as it has been generally imagined, but absolutely essential to its very nature and being : so that when bodies are di vested of these powers, they become no thing at all. In another place, Dr. Priest ley has given a somewhat different ac count of matter : according to which it is only a number of centres of attraction and repulsion ; or more properly of cen tres, not divisible, to divine agen. cy is directed ; and as sensation and thought are not incompatible with these powers, solidity, or impenetrability, and consequently a vis inertia only having been thought repugnant to them, he maintains, that we have no reason to sup pose, that there are in man two sub stances absolutely distinct from each other. See " Disquisitions on Matter and Spirit." But Dr. Price, in a correspondence with Dr. Priestley, published tinder the title of "A Free Discussion of the Doc trines of Materialism and Philosophical Necessity," 1778, has suggested a variety of unanswerable objections against this hypothesis of the penetrability of matter, and against the conclusions that are drawn from it. The vis inertia of mat ter, he says, is the foundation of all that is demonstrated by natural philosphers concerning the laws of the collision of bodies. This, in particular, is the foun dation of Newton's philosophy, and es pecially of his three laws of motion. Solid matter has the power of acting on other matter by impulse.; and this is the only wayin which it is capable of acting, by any action that is properly its own. If it be said, that one particle of matter can act upon another without contact and impulse, or that matter can, by its own proper agency, attract or repel other matter which is at a distance from it, then a maxim hitherto universally received must be false, that " nothing can act where it is not." Newton, in his letters to Bent ley, calls the notion, that matter possess es an innate power of attraction, or that it can act upon matter at a distance, and attract and repel by its own agency, an abSurclity, into which he thought no one could possibly fall. And in another place he expressly disclaims the notion of in nate gravity, and has taken pains to shew that he did not take it to be an es sential property of bodies. By the same kind of reasoning pursued, it must ap pear, that matter has not the power of attracting and repelling; that this power is the power of some foreign cause, act ing upon matter according to stated laws; and, consequently, that attraction and repulsion, not being actions, much less inherent qualities of matter, as such it ought not to be defined by them. And if matter has no other property, as Dr. Priestley asserts, than the power of at tracting and repelling, it must be a non entity ; because this is a property that cannot belong to it. Besides, all power is the power of something; and yet, if matter is nothing but this power, it must be the power of nothing ; and the very idea of it is a contradiction.