Chapter 20
In the last figure, when both premises are contingent, and when only one is contingent, there will be a syllogism, therefore when the premises signify the contingent, the conclusion will also be contingent; also if one premise signifies the contingent, but the other, the simple inesse. Still when one premise is assumed necessary, if it be affirmative, there will not be a conclusion either necessary or simple, if on the contrary it is negative, there will be a syllogism of the simple non-inesse as before; in these however the contingent must be similarly taken in the conclusions. First then let the premises be contingent, and let A and B be contingently present with every C; since therefore a particular affirmative is convertible, but B is contingent to every C, C will also be contingent to a certain B, therefore if A is contingent to every C, but C is contingent to a certain B, it is necessary also that A should be contingent to a certain B, for the first figure is produced. If again A is contingently present with no C, but B with every C, A must also of necessity be contingently not present with a certain B, for again there will be the first figure by conversion; but if both propositions be assumed negative from these the necessary will not result, but the propositions being converted there will be a syllogism as before. For if A and B are contingently not present with C,
