Page:Mathematical collections and translations, in two tomes - Salusbury (1661).djvu/54

 ruptible, aswell as the Elementary, what will you say then?

I will say you have done that which is impossible to be done.

Go to; tell me, Simplicius, are not these affections contrary to one another?

Which?

Why these; Alterable, unalterable; passible, *impassible; generable, ingenerable; corruptible, incorruptible?

They are most contrary.

Well then, if this be true, and it be also granted, that Cœlestial Bodies are ingenerable and incorruptible; I prove that of necessity Cœlestial Bodies must be generable and corruptible.

This must needs be a Sophism.

Hear my Argument, and then censure and resolve it. Cœlestial Bodies, for that they are ingenerable and incorruptible, have in Nature their contraries, which are those Bodies that be generable and corruptible; but where there is contrariety, there is also generation and corruption; therefore Cœlestial Bodies are generable and corruptible.

Did I not say it could be no other than a Sophism? This is one of those forked Arguments called Soritæ: like that of the Cretan, who said that all Cretans were lyars; but he as being a Cretan, had told a lye, in saying that the Cretans were lyars; it followed therefore, that the Cretans were no lyars, and consequently that he, as being a Cretan, had spoke truth: And yet in saying the Cretans were lyars, he had said true, and comprehending himself as a Cretan, he must consequently be a lyar. And thus in these kinds of Sophisms a man may dwell to eternity, and never come to any conclusion.

You have hitherto censured it, it remaineth now that you answer it, shewing the fallacie.

As to the resolving of it, and finding out its fallacie, do you not in the first place see a manifest contradiction in it? Cœlestial Bodies are ingenerable and incorruptible; Ergo, Cœlestial Bodies are generable and corruptible. And again, the contrariety is not betwixt the Cœlestial Bodies, but betwixt the Elements, which have the contrariety of the Motions, sursùm and deorsùm, and of levity and gravity; But the Heavens which move circularly, to which motion no other motion is contrary, want contrariety, and therefore they are incorruptible.

Fair and softly, Simplicius; this contrariety whereby you say some simple Bodies become corruptible, resides it in the same Body which is corrupted, or else hath it relation to some other? I say, if, for example, humidity by which a piece of Earth