Original letter from Isaac Newton to Richard Bentley, dated 10 December 1692

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S^r

When I wrote my treatise about o^r Systeme I had an eye upon such Principles as might work w^th considering men for y^e beleife of a Deity & nothing can rejoyce me more then to find it usefull for that purpose But if I have done y^e publick any service this way 'tis due to nothing but industry & a patient thought.

As to yo^r first Query, it seems to me that if the matter of o^r Sun & Planets & all y^e matter in the Vniverse was eavenly scattered throughout all the heavens, & every particle had an innate gravity towards all the rest & the whole space throught|o|ut w^ch this matter was scattered, was but finite: the matter on y^e outside of this space would by its gravity tend towards all y^e matter on the inside & by consequence fall down to y^e middle of the whole space & there compose one great spherical mass But if thi|e| matter was eavenly diffused through an infinite space, it would not never convene into one mass but some of it convene into one mass & some into another so as to make an infinite number of great masses scattered at great distances from one another throughout all y^t infinite space. And thus might y^e Sun and ffixt stars be formed supposing the matter were of a lucid nature. But how the matter should divide it self into two sorts & that part of it w^ch is fit to compose a shining body should fall down into one mass & make a Sun & the rest w^ch is fit to compose an opake body should coalesce not into one \great/ body like y^e shining matter but into many little ones: or if the Sun was at first an opake body like y^e Planets or y^e Planets lucid bodies like y^e 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 y^e counsel & contrivance of a voluntary Agent. The same power whether natural or supernatural, w^ch placed y^e Sun in the center of the orbs of y^e six primary Planets, placed Saturn in the center of y^e orbs of his satellites \five/ secondary Planets & Iupiter in y^e center of \the orbs of/ his four secondary ones & y^e earth in y^e center of the Moons orb; & therefore had this cause been a blind one w^thout contrivance & designe the Sun would have been a body of the same kind w^th Saturn \Iupiter/ & y^e earth, that is without light & heat. Why there is one body in o^r Systeme qualified to give light & heat to all y^e rest I know no reason but because the author of y^e Systeme thought {illeg} it convenient, & why there is but one body of this kind I know no reason but because one was sufficient to warm & enlighten all the rest. ffor the Cartesian Hypothesis of Sun's loosing their light & then turning into Planets Comets & Comets into Planets can have no place in my systeme & is plainly erroneous because its certain that Comets as often as they appear to us descend into the <4v> system of o^r Planets lower then y^e orb of Iupiter & sometimes lower then the orbs of {illeg} Venus & Mercury, & yet never stay here but always return from the Sun with the same degrees of motion by w^th {sic} they approached him.

To your second Query I answer that y^e motions w^ch y^e Planets now have could not spring from any naturall cause alone but were imprest by an intelligent Agent. ffor since Comets descend into y^e region of o^r Planets & here move all manne{r} of ways going sometimes the same way w^th the Planets sometimes the contrary way & sometimes in cross ways in planes inclined to y^e plane of the Ecliptick at all kinds of angles: its plaine that there is no naturall cause w^ch could determin all y^e Planets |both primary & secondary| to move y^e same way & in y^e same plane w^thout any considerable variation. This must have been the effect of Counsel. Nor is there any natural cause w^ch could give the Planets those just degrees of velocity in proportion to their distances from y^e Sun & other central bodies about w^ch they move & to y^e quantity of matter conteined in those bodies, w^ch 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 y^e Sun (as they would have been, had their motions been caused by their gravity, o|w|hereby the matter at the first formation of y^e Planets might fall from y^e remotest regions towards y^e Sun) they {illeg} they would not move in concentric orbs but in such excentric ones as y^e Comets move in. Were all the Planets as swift as Mercury or as slow as Saturn or his Satellites, or were their \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 Saturn from the centers about w^ch they move been greater or less then they are w^th y^e same velocities; or had the quantity of matters in the Sun or in {I} Saturn Iupiter & the earth \& by consequence their gravitating power{s}/ been greater or less then it is: the primary Planets could not have revolved about y^e Sun nor y^e secondary ones about \Saturn Iupiter &/ y^e 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 w^th all its motions, required a Cause w^ch understood & compared together the quantities of matter in y^e several bodies of y^e Sun & Planets {illeg} |& y^e| gravitating powers resulting from thence, the \several/ distances of the primary Planets from y^e Sun & secondary ones from Saturn Iupiter & y^e earth, & y^e velocities w^th w^ch the|se| Planets could revolve at those distances about those quantities of matter in y^e central bodies. And to compare & adjust all these things together {illeg} in so great a variety of bodies argues that cause to be not blind & fortuitous, but very well skilled in Mechanicks & Geometry.

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To your third Query I answer that it may be reprented {sic} that the Sun may |by| heat|ing| those Planets most w^ch are nearest to him cause them to be better concocted & more condensed by concoction. But when I consider that o^r earth is much more heated in its bowells by|e|low the upper crust by subterraneous fermentations of mineral bodies then by the Sun, I see not why the interior parts of Iupiter & Saturn might \not/ be as much \heated/ concocted & coagulated by those fermentions {sic} as our earth is, & therefore this various density should have some other cause then y^e various distances of y^e Planets from y^e Sun: & I am confirmed in this opinion by considering that the Planets of Iupiter & Saturn as they are rarer then the rest so they are vastly greater & contein a far greater quantity of matter & have many Satellites about them: w^ch qualifications surely arose not from their being placed at so great a distance from y^e Sun but were rather y^e cause why the creater placed them at y^t great distance. ffor \by their gravitating powers/ they disturb one anothers motions very sensibly as I find by some late Observations of M^r Flamsteed, & had they been placed much nearer to y^e Sun & to one another they would by the same powers have caused a considerable disturbance in the whole Systeme.

To y^e 4^th Query I answer that in y^e Hypotheses of Vort{ices} the inclination of y^e axis of y^e earth might in my opin{ion be} ascribed to y^e situation of y^e earth's vortex before it was {absorbed} by y^e neighbouring vortices & y^e earth turned from a Sun {to a} Comet; but this inclination ought constantly to decrease in {compli}ance w^th y^e motion of the earths vortex, whose axis is {much less} inclined to y^e Ecliptick as appears by y^e 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 af{fect their} diurnal motions.

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

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

Yo^r most humble Servant to command

Is. Newton.

Cambridge Dec. 10^th

1692.

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For the R^d D^r Bentley
at the B^p of Worcester's House
in Park stret in

Westminster

London