Newton to Bentley, December 10, 1692




††††† When I wrote my treatise bout our Systeme I had an eye upon such Principles as might work with considering men for the belief of a Deity and nothing can rejoyce me more than to find it usefull for that purpose. But if I have done the publick any service this way ítis due to nothing but industry and patient thought.


††††† As to your first Query, it seems to me, that if the matter of our Sun and Planets and all the matter in the Universe was eavenly 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 to the middle of the whole space and there compose one great spherical mass. But if the matter was eavenly diffused through an infinite space, it would never convene into one mass but some of it 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 Fixt stars be formed supposing the matter were of a lucid nature. But how the matter should divide it self 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 opake body should coalesce not into one great body like the shining matter but into many little ones: or if the Sun was at first an opake 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 opake or all they be changed into opake ones whilst he remains unchanged, I do not think explicable by mere natural causes but am forced to ascribe it to the counsel and contrivance of a voluntary Agent. The same power, whether natural or supernatural, which placed the Sun in the center of the Orbs of the six primary Planets, placed Saturn in the center of the orbs of his five secondary Planets and Jupiter in the center of the orbs of his four secondary ones and the earth in the center of the Moons orb; and therefore had this cause been a blind one without contrivance and designe the Sun would have been a body of the same kind with Saturn Jupiter and the earth, that is without light and heat. Why there is one body in our Systeme qualified to give light and heat to all the rest I know reason but because the author of the Systeme thought it convenient, and why there is but one body of this kind I know no reason but because one was sufficient to warm and enlighten all the rest. For the Cartesian Hypothesis of the Sunís loosing their light and then turning into Comets and Comets into Planets can have no place in my systeme and is plainly erroneous because its certain that Comets as often as they appear to us descend into the system of our planets lower then the orb of Jupiter and sometimes lower then the orbs of Venus and Mercury, and yet never stay here but always return from the Sun with the same degrees of motion by which they approached him.


††††† To your second Query I answer that the motions which the Planets now have could not spring from any naturall cause alone but were imprest by an intelligent Agent. For since Comets descend into the region of our planets and here move all manner of ways going sometimes the same way with the Planets sometimes the contrary way and sometimes in cross ways in planes inclined to the plane of the Ecliptick at all kinds of angles: its plaine that there is no naturall cause which could determine all the Planets both primary and secondary to move the same way and in the same plane without any considerable variation. This must have been the effect of Counsel. Nor is there any natural cause which could give the Planets those just degrees of velocity in proportion to their distances from the Sun and other central bodies about which they move and to the quantity of matter conteined in those bodies, which were requisite to make them move in concentrick orbs about those bodies. Had the Planets been as swift as Comets in proportion to their distances from the sun (as they would have been, had their motions been caused by their gravity, whereby the matter at the first formation of the Planets might fall from the remotest regions towards the Sun) they would not move in concentric orbs but in such excentric ones as the Comets move in. Were all the Planets as swift as mercury or as slow as Saturn or his Satellites, or were there several velocities otherwise much greater or less then they are (as they might have been had they arose from any other cause then their gravity) or had their distances from the centers about which they move been greater or less then they are with the same velocities; or had the quantity of matter in the Sun or in Saturn, Jupiter and the earth and by consequence their gravitating power been greater or less then it is: the primary Planets could not have revolved about the Sun nor the secondary ones about Saturn, Jupiter and the earth in concentrick circles as they do, but would have moved in Hyperbolas or Parabolas or in Ellipses very excentric. To make this systeme therefore with all its motions, required a Cause which understood and compared together the quantities of matter in the several bodies of the Sun and Planets and the gravitating powers resulting from thence, the several distances of the primary Planets from the Sun and secondary ones from Saturn Jupiter and the earth, and the velocities with which these planets could revolve at those distances about those quantities of matter in the central bodies. And to compare and adjust all these things together in so great a variety of bodies argues that cause to be not blind and fortuitous, but very well skilled in Mechanicks and Geometry.


To your third Query I answer that it may be represented that the Sun may be heating those Planets most which are nearest to him to cause them to be better concocted and more condensed by concoction. But when I consider that our earth is much more heated in its bowells below the upper crust by subterraneous fermentations of mineral bodies then by the Sun, I see not why the interior parts of Jupiter and Saturn might not be as much heated concocted and coagulated by those fermentations as our earth is, and therefore this various density should have some other cause then the various distances of the Planets from the Sun: and I am confirmed in this opinion by considering that the Planets of Jupiter and Saturn as they are rarer then the rest so they are vastly greater and contein a far greater quantity of matter and have many Satellites about them: which qualifications surely arose not from their being placed at so great a distance from the Sun but were rather the cause why the creator placed them at that great distance. For by their gravitating powers they disturb one anothers motions very sensibly as I find by some late Observations of Mr Flamsteed, and had they been placed much nearer to the Sun and to one another they would by the same powers have caused a considerable disturbance in the whole Systeme.


††††† To the 4th Query I answer that in the Hypotheses of Vortices the inclination of the axis of the earth might in my opinion be ascribed to the situation of the earthís vortex before it was absorbed by the neighbouring vortices and the earth turned from a Sun to a Comet; but this inclination ought constantly to decrease in compliance with the motion of the earths vortex, whose axis is much less inclined to the Ecliptick as appears by the motion of the Moon carried about therein. If the sun by his rays could carry about the Planets, yet I do not see how he could thereby affect their diurnal motions.


††††† Lastly I see nothing extraordinary in the inclination of the Earthís axis for proving a Deity unless you will urge it as a contrivance for winter and for summer and for making the earth habitable towards the poles, and that the diurnal rotations of the Sun and Planets as they could hardly arise from any cause purely mechanical, so by being determined all the same way with the annual and menstrual motions they seem to make up that harmony in the systeme which (as I explained above) was the effect of choice rather then of chance.


††††† There is yet another argument for a Deity which I take to be a very strong one, but till principles on which tis grounded be better received I think it more advisable to let it sleep. I am


Your most humble Servant to command


Is. Newton