it: for the starry heaven (say they) does not finish his course under 26000 years; whereas Saturn, which is next unto it, does compass his orb in thirty years. From whence it will probably follow, that there is a very great distance betwixt these in place, because they have such different terms of their revolutions. But against this answer unto the last argument, our adversaries thus reply: 1. If the fixed stars are so far distant from us, that our approaching nearer unto them by 1000000 German miles, does not make any sensible difference in their appearance; then Galilæus's perspective could not make them seem of a bigger form than they do to the bare eye, which yet is contrary to common experience*. 2. From hence it may be inferred, that the least fixed star is bigger than all this orb wherein we suppose the earth to move; because there is none of them but are of a sensible bigness in respect of the firmament, whereas this it seems is not †. 3. Since God did at first create the stars for the use of all nations that are under the whole heavens, Deut. iv. 19. it might have argued some improvidence in him, if he had made them of such vast magnitudes; whereas they might as well bestow their light and influences, and so consequently be as serviceable to that end for which they were appointed, if they had been made with less bodies, and placed nearer unto us. And it is a common maxim, that nature in all her operations, does avoid superfluities, and use the most compendious way . I answer: 1. To the first, whether the perspective do make the fixed stars appear bigger than they do to the bare eye, cannot certainly be concluded, unless we had such an exact glass, by which we might try the experiment. But if in this kind we will trust the authority of others, Keplar || tells *Fromond. Vesta, tract. 5. cap. 1. † Ibid. Ibid. us from the experience of skilful men, that the better the perspective is, by so much the less will the fixed stars appear through it, being but as meer points, from which the beams of light do disperse themselves like hairs. And it is commonly affirmed by others, that the dog-star, which seems to be the biggest star amongst those of the first magnitude, does yet appear through this glass but as a little point no bigger than the fiftieth part of Jupiter, Hence it is, that though the common opinion hold the stars of the first magnitude to be two minutes in their diameter, and Tycho three; yet Galilæus *, who hath been most versed in the experiments of his own perspective concludes them to be but five seconds. 2. To the second: first we affirm, the fixed stars to be of a vast magnitude. But however, this argument does not induce any necessity that we should conceive them so big as the earth's orb. For it might easily be proved, that though a star of the sixth magnitude were but equal in diameter unto the sun (which is far enough from the greatness of the earth's orb;) yet the starry heaven would be at such a distance from us, that the earth's annual motion could not cause any difference in its appearance. Suppose the diameter of the sun to be about half a degree †, as our adversaries grant; whereas a star of the sixth magnitude is 50 thirds, which is comprehended in that of the sun 2160 times. Now if the sun were removed so far from us, that its diameter would seem but as one of that number whereof it now contains 2160; then must his distance from us be 2160 times greater than now it is: which is all one, as if we should say, that a star of the sixth magnitude is severed from us by so many semidiameters of the earth's orb. But now according to common consent, the distance of the earth from the sun does contain 128 semidiameters of the earth, and (as was said before) this supposed distance of the fixed stars does comprehend 2160 semidiameters of the earth's orb. From whence it is manifest, that the semidiameter of the earth, in com Vid. Gal. ibid. System. Mundi. Coll. 3. parison to its distance from the sun, will be almost doubly bigger than the semidiameter of the earth's orb, in comparison to this distance of the stars. But now, the semidiameter of the earth does make very little difference in the appearance of the sun, because we see common observations upon the surface of it, are as exactly true to the sense as if they were made from the centre of it. Wherefore, that difference which would be made in these fixed stars, by the annual course of the earth, must needs be much more unobservable, or rather altogether insensible. 2. The consequence of this argument is grounded upon this false supposition, that every body must necessarily be of an equal extension to that distance from whence there does not appear any sensible difference in its quantity. So that when I see a bird flying such a height in the air, that my being nearer unto it, or farther from it, by ten or twenty foot, does not make it seem unto my eyes either bigger or less; then I may conclude, that the bird must needs be either ten or twenty foot thick: Or when I see the body of a tree that may be half a mile from me, and perceive that my approaching nearer to it by 30 or 40 paces, does not sensibly make any different appearance, I may then infer, that the tree is forty paces thick; with many the like absurd consequences, that would follow from that foundation upon which this argument is bot tomed. To the third I answer: it is too much presumption, to conclude that to be superfluous, the usefulness of which we do not understand. There be many secret ends in these great works of Providence, which human wisdom cannot reach unto; and as Solomon speaks of those things that are under the sun, so may we also of those things that are above it; that no man can find out the works of God; for though a man labour to seek it out, yea further, though a wise man think to know it, yet shall he not be able to find it *. He that hath most insight into the works of nature, is not able to give a satisfying reason, why the * Eccles. viii. 17. planets or stars should be placed just at this particular distance from the earth, and no nearer or farther. And besides, this argument might as well be urged against the hypothesis of Ptolemy or Tycho, since the stars, for ought we know, might have been as serviceable to us, if they had been placed far nearer, than either of those authors suppose them. Again, were there any force in such a consequence, it would as well conclude a great improvidence of nature, in making such a multitude of those lesser stars, which have lately been discovered by the perspective. For to what purpose should so many lights be created for the use of man, since his eyes were not able to discern them? So that our disability to comprehend all those ends which might be aimed at in the works of nature, can be no sufficient argument to prove their superfluity. Though scripture do tell us that these things were made for our use, yet it does not tell us, that this is their only end. It is not impossible, but that there may be elsewhere some other inhabitants, by whom these lesser stars may be more plainly discerned. And (as was said before) why may not we affirm that of the bigness, which our adversaries do concerning the motion of the heavens? That God, to shew his own immensity, did put a kind of infinity in the creature. There is yet another argument to this purpose, urged by Al. Ross *. which was not referred to any of the former kind, because I could scarcely believe I did rightly understand it; since he puts it in the front of his other arguments, as being of strength and subtilty enough to be a leader unto all the rest; and yet in the most likely sense of it, it is so extremely simple to be pressed in a controversy, that every fresh-man would laugh at it. The words of it are these: Quod minimum est in circulo debet esse centrum illius; at terra longe minor est sole, & æquinoctialis terrestris est omnium in cælo circulus minimus; ergo, &c. By the same reason, it would rather follow, that the *Lib. 1. sect. 2. c. I. moon or Mercury were in the centre, since both these are less than the earth. And then, whereas he says that the æquinoctial of the earth is the least circle in the heavens, it is neither true nor pertinent, and would make one suspect, that he who should urge such an argument, did scarce understand any thing in astronomy. There are many other objections like unto this, not worth the citing: the chief of all have been already answered; by which you may discern, that there is not any such great necessity as our adversaries pretend, why the earth should be situated in the midst of the universe. PROP. VII. It is probable that the Sun is in the centre of the world. THE Τ truth, are chief reasons for the confirmation of this implied in the conveniences of this hypothesis above any other; whereby we may resolve the motions and appearances of the heavens into more easy and natural causes. Hence will the frame of nature be freed from that deformity which it has according to the system of Tycho ; who though he make the sun to be in the midst of the planets, yet without any good reason denies it to be in the midst of the fixed stars; as if the planets, which are such eminent parts of the world, should be appointed to move about a distinct centre of their own, which was beside that of the universe. Hence likewise are we freed from many of those inconveniences in the hypothesis of Ptolemy, who supposed in the heavens, epicycles and eccentrics, and other orbs, which he calls the deferents of the apoge and perige. As if nature in framing this great engine of the world, had been put unto such hard shifts, that she was fain to make use of wheels and screws, and other the like artificial instruments of motion. |