Explanation of the FRONTISPIECE.

THE idea is taken from 1 Cor. iii. 12, where different perfons are reprefented as having built with different materials, on the folid foundation of chriftianity, as laid by Chrift and the apostles; and that what was built with wood, and other bafe materials, would be confumed by fire, while the reft would stand. Our Saviour, who revealed the future ftate of his church to the apostle John, is reprefented as fhewing him this circumftance relating to it. The application of this fcene to the object of this work, is fufficiently obvious.

d

SECTION I.

Of the Nature and effential Properties of

MATTER.

AM forry to have occafion to begin these difquifitions on the nature of matter and fpirit, with defiring my reader to recur to the univerfally received rules of philofophizing, fuch as are laid down by Sir Ifaac Newton at the beginning of his third book of Principia. But though we have followed these rules. pretty closely in other philofophical researches, it appears to me that we have, without any reafon in the world, intirely deferted them in this. We have suffered ourselves to be guided by them in our inquiries into the causes of particular appearances in nature, but have formed our notions, with respect to the most general and comprehenfive principles of human knowledge, without the leaft regard, nay in direct contradiction, to them. And I am willing to hope, that when this is plainly pointed out, the inconfiftency of our conduct in these cafes cannot fail to ftrike us, and be the means of inducing the philofophical part of the world to tread back their fteps, and fet out again on the fame maxims which they

have actually followed in their progress. For my own part, I profess an uniform and rigorous adherence to them; but then I muft require that my own reafoning be tried by this, and by no other test.

The first of these rules, as laid down by Sir Ifaac Newton, is that we are to admit no more caufes of things than are fufficient to explain appearances; and the fecond is that, to the fame effects we must, as far as poffible, affign the fame caufes.

So long as we follow these maxims, we may be confident that we walk on fure ground; but the moment we depart from them, we wander in the regions of mere fancy, and are only entertaining ourselves and others with our own crude imaginations and conceits. By these plain rules, then, let us pursue our inquiries concerning the nature and connection of what have been called material and thinking fubftances; concerning both which very great mifconceptions feem to have very generally prevailed. And in the first place, let us attend to what metaphyficians and philofophers have advanced concerning matter, with respect to which (I mean its fundamental properties, and what may be abfolutely affirmed or denied concerning them) there are very few who have fo much as expreffed the leaft doubt or uncertainty.

It is afferted, and generally taken for granted, that matter is neceffarily a folid, or impenetrable fubftance, and naturally, or of itfelf,

felf, deftitute of all powers whatever, as those of attraction or repulfion, &c. or, as it is commonly expreffed, that matter is poffeffed of a certain vis inertia, and is wholly indifferent to a state of reft or motion, but as it is acted upon by a foreign power.

That the vulgar fhould have formed these opinions, and acquiefce in them, I do not wonder; because there are common appearances enow which must neceffarily lead them to form fuch a judgment. I prefs my hand against the table on which I am writing, and finding that I cannot penetrate it, and that I cannot push my hand into the place which it occupies, without firft pushing it out of its place, I conclude that this table, and by analogy, all matter is impenetrable to other matter. These first appearances are fufficient for them to conclude, that matter is neceffarily Jolid, and incapable of yielding to the impreffion of other folid matter.

Again, I fee a billiard table; and though I obferve the balls upon it ever fo long, I do not find any of them ever to change their places till they are pushed againft; but that when once they are put in motion, they continue in that new ftate till they are stopped, either by fome obftacle, or their own friction, which is in fact the refult of a series of obftacles. And therefore I conclude, that, had there been no obftacle of any kind in the way, a ball would have continued in that state of motion (as, without being impelled by a fo

B 2

reign

reign force, it would have continued in its former ftate of rest) for ever; having no power within itself to make any change in either of thofe ftates. I therefore conclude univerfally, that all matter, as fuch, is entirely deftitute of power, and whatever is true of larger bodies with refpect to each other, must be equally true of the fmallest component parts of the fame body; and confequently that all attraction or repulfion must be the effect of fome foreign power, difposing either larger bodies, or their fmall component parts, to certain motions and tendencies, which otherwife they would not have had.

Such appearances as thefe, I imagine, have led to the conclufions above mentioned, concerning the fundamental properties of matter.. But then they are no more than fuperficial appearances, and therefore have led to fuperficial and falfe judgements; judgements which the real appearances will not authorize. For, in fact, when the appearances above mentioned are confidered in the new and juft lights which late obfervations have thrown upon this part of philofophy, they will oblige us, if we adhere to the rules of philofophizing laid down above, to conclude that resistance, on which alone our opinion concerning the folidity or impenetrability of matter is founded, is never occafioned by folid matter, but by fomething of a very different nature, viz. a power of re·pulfion always acting at a real, and in general an affignable diftance from what we call the

body