Book, Paragraph

 1      I, 6 |      produced. It is possible to demonstrate this also per impossibile
 2      I, 6 | preceding. And it is possible to demonstrate it also per impossibile
 3      I, 10|        same terms can be used to demonstrate the point, which were used
 4      I, 27| predicates it is not possible to demonstrate another predicate, save
 5      I, 27|        the more cogently will he demonstrate. But he must select not
 6      I, 30|        to discover the proof and demonstrate everything which admitted
 7      I, 41|     though it were impossible to demonstrate without these illustrative
 8      I, 41|  illustrative terms, as it is to demonstrate without the premisses of
 9     II, 5 |        for it is not possible to demonstrate through these terms that
10     II, 5 |   convertible, it is possible to demonstrate everything reciprocally,
11     II, 5 | syllogisms it is not possible to demonstrate the universal premiss through
12     II, 5 |      Clearly it is impossible to demonstrate the universal premiss: for
13     II, 16|          a species of failure to demonstrate the problem proposed; but
14     II, 16|         the thesis proposed, and demonstrate it through them, e.g. if
15     II, 16|        which it is impossible to demonstrate unless the parallels exist.