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FROM SIR ISAAC NEWTON TO DR. BENTLEY, CONTAINING
IT will certainly be required, that notice should be
taken of a book, however small, written on such a subject, by such an author. Yet I know not whether these Letters will be very satisfactory, for they are answers to inquiries not published; and therefore, though they contain many positions of great importance, are, in some parts, imperfect and obscure, by their reference to Dr. Bentley's Letters.
Sir Isaac declares, that what he has done is due to nothing but industry and patient thought; and indeed long consideration is so necessary in such abstruse inquiries, that it is always dangerous to publish the productions of great men, which are not known to have been designed for the press, and of which it is uncertain, whether much patience and thought have been bestowed upon them. The principal question of these Letters gives occasion to observe how even the mind of Newton gains ground gradually upon darkness.
"As to your first query," says he, "it seems to me, that if the matter of our sun and planets, and all the
* Literary Magazine, Vol. I. 1756, p. 89.
matter of the universe, were evenly scattered throughout all the heavens, and every particle had an innate gravity towards all the rest, and the whole space throughout which this matter was scattered, was but finite ; the matter on the outside of this space would by its gravity tend towards all the matter on the inside, and by consequence fall down into the middle of the whole space, and there compose one great spherical mass. But if the matter was evenly disposed throughout an infinite space, it could never convene into one mass ; but some of it would convene into one mass, and some into another, so as to make an infinite number of great masses, scattered at great distances from one to another throughout all that infinite space. And thus might the sun and fixed stars be formed, supposing the matter were of a lucid nature. But how the matter should divide itself into two sorts, and that part of it which is fit to compose a shining body, should fall down into one mass and make a sun, and the rest, which is fit to compose an opaque body, should coalesce, not into one great body like the shining matter; but into many little ones ; or if the sun at first were an opaque body like the planets, or the planets lucid bodies like the sun, how he alone should be changed into a shining body, whilst all they continue opaque, or all they be changed into opaque ones, whilst he remains unchanged, I do not think more explicable by mere natural causes, but am forced to ascribe it to the counsel and contrivance of a voluntary agent.”
The hypothesis of matter evenly disposed through infinite space, seems to labour with such difficulties, as
makes it almost a contradictory supposition, or a supposition destructive of itself.
Matter evenly disposed through infinite space, is either created or eternal; if it was created, it infers a Creator ; if it was eternal, it had been from eternity evenly spread through infinite space; or it had been once coalesced in masses, and afterwards been diffused. Whatever state was first, must have been from cternity, and what had been from eternity could not be changed, but by a cause beginning to act as it had never acted before, that is, by the voluntary act of some external power. If matter infinitely and evenly diffused was a moment without coalition, it could never coalesce at all by its own power. If matter originally tended to coalesce, it could never be evenly diffused through infinite space. Matter being supposed eternal, there never was a time when it could be diffused before its conglobation, or conglobated before its diffusion.
This Sir Isaac seems by degrees to have understood ; for he says, in his second Letter, “ The reason why matter evenly scattered through a finite space would convene in the midst, you conceive the same with me ; but that there should be a central particle, so accurately placed in the middle, as to be always equally attracted on all sides, and thereby continue without motion, seems to me a supposition fully as hard as to make the sharpest needle stand upright upon its point on a looking glass. For if the very mathematical centre of the central particle be not accurately in the very mathematical centre of the attractive power of the whole mass, the particle will not be attracted equally on all sides. And much harder
is it to suppose all the particles in an infinite space should be so accurately poised one among another, as to stand still in a perfeci equilibrium. For I reckon this as hard as to make not one needle only, but an infinite number of them, so many as there are particles in an infinite space, stand accurately poised upon their points. Yet I grant it possible, at least by a divine power ; and if they were once to be placed, I agree with you that they would continue in that posture, without motion for ever, unless put into new motion by the same power. When therefore I said, that matter evenly spread through all space, would convene by its gravity into one or more great masses, I understand it of matter not resting in an accurate poise."
Let not it be thought irreverence to this great name, if I observe, that by matter evenly spread through infinite space, he now finds it necessary to mean matter not. evenly spiread. Matter not evenly spread will indeed convene, but it will convene as soon as it exists. And, in my opinion, this puzzling question about matter is only how that could be that never could have been, or what a man thinks on when he thinks of nothing.
Turn matter on all sides, make it eternal, or of late production, finite or infinite, there can be no regular system produced but by a voluntary and meaning agent. This the great Newton always asserted, and this he asserts in the third letter ; but proves in another manner, in a manner perhaps more happy and conclusive.
“ The hypothesis of deriving the frame of the world by mechanical principles from matter evenly spread through the heavens being inconsistent with my system, I had considered it very little before your letter put me upon it, and therefore trouble you with a line or two more about it, if this comes not too late for your use.
“In my former I represented that the diurnal rotations of the planets could not be derived from gravity, but required a divine arm to impress them. And though gravity might give the planets a motion of descent towards the sun, either directly, or with some little obliquity, yet the transverse motions by which they revolve in their several orbs, required the divine arm to impress them according to the tangents of their orbs. I would now add, that the hypothesis of matter's being at first evenly spread through the heavens, is, in my opinion, inconsistent with the hypothesis of innate gravity, without a supernatural power to reconcile them, and therefore it infers a Deity. For if there be innate gravity it is impossible now for the matter of the earth, and all the planets and stars, to fly up from them, and become evenly spread throughout all the heavens without a su. pernatural power ; and certainly that which can never be hereafter without a supernatural power, could never be heretofore without the same power."