Tis reported of _Aristotle_ that when hee saw the bookes of _Moses_ he commended them for such a majesticke stile as might become a God, but withall hee censured that manner of writing to be very unfitting for a Philosopher because there was nothing proved in them, but matters were delivered as if they would rather command than perswade beliefe. And ’tis observed that hee sets downe nothing himselfe, but he confirmes it by the strongest reasons that may be found, there being scarce an argument of force for any subject in Philosophy which may not bee picked out of his writings, and therefore ’tis likely if there were in reason a necessity of one onely world, that hee would have found out some such necessary proofe as might confirme it: Especially since hee labours for it so much in two whole Chapters. But now all the arguments which he himselfe urges in this subject,[1] are very weake and farre enough from having in them any convincing power. Therefore ’tis likely that a plurality of worlds doth not contradict any principle of reason. However, I will set downe the two chiefe of his arguments from his owne workes, and from them you may guesse the force of the other. The 1. is this,[2] since every heavy body doth naturally tend downwards, and every light body upwards, what a hudling and confusion must there bee if there were two places for gravity and two places for lightnesse: for it is probable that the Earth of that other World would fall downe to this Center, and so mutually the aire and fire here ascend to those Regions in the other, which must needes much derogate from the providence of nature, and cause a great disorder in his workes. To this I answere, that if you will consider the nature of gravity, you will plainely see there is no ground to feare any such confusion, for heavinesse is nothing else but such a quality as causes a propension in ’its subject to tend downewards towards its owne Centre, so that for some of that earth to come hither would not bee said a fall but an ascension, since it moved from its owne place, and this would bee impossible (saith _Ruvio_) because against nature,[3] and therefore no more to bee feared than the falling of the Heavens. [Sidenote 1: _De Cœlo_ l. 1. c. 8. 9.] [Sidenote 2: _Ibid._] [Sidenote 3: _De Cœlo_ l. 1. c. 9. q. 1.] Another Argument hee had from his master _Plato_,[1] that there is but one World, because there is but one first mover, God.[2] [Sidenote 1: _Metaphys._ l. 12. c. 8.] [Sidenote 2: _Diog. Laert. lib._ 3.] But here I may deny the consequence, since a plurality of worlds doth not take away the unity of the first mover. _Vt enim forma substantialis, sic primum efficiens apparentem solummodo multiplicitatem induit per signatam materiam_