Questio de aqua et terra (32)

(32) Maior vero huius demonstrationis demonstratur in theorematibus geometricis; et demonstratio est ostensiva, licet vim suam habeat, ut in hiis que demonstrate sunt superius, per impossibile. (32) Now the major premise of this demonstration is demonstrated in geometrical theorems; and the demonstration is conclusive, although it derives its force (as in the case of our own proofs above) from a reductio ad impossibile.