Page:O. F. Owen's Organon of Aristotle Vol. 1 (1853).djvu/135

 instances, when the contingent proposition is converted. For let A be present with every B, but B contingent to no C, now when the terms are thus, there will be nothing necessary inferred, but if B C be converted, and B be assumed to be contingent to every C, a syllogism arises as before, since the terms have a similar position. In the same manner, when both the propositions are negative, if A B signifies not being present, but B C to be contingent to no individual, through these assumptions no necessity arises, but the contingent proposition being converted, there will be a syllogism. Let A be assumed present to no B, and B contingent to no C, nothing necessary is inferred from these; but if it is assumed that B is contingent to every C, which is true, and the proposition A B subsists similarly, there will be again the same syllogism. If however B is assumed as not present with C, and not that it happens not to be present, there will by no means be a syllogism, neither if the proposition A B be negative nor affirmative; but let the common terms of necessary presence be "white," "animal," "snow," and of non-contingency "white," "animal," "pitch." It is evident, therefore, that when terms are universal, and one of the propositions is assumed, as simply de inesse, but the other contingent, when the minor premise is assumed contingent, a syllogism always arises, except that sometimes it will be produced from the propositions themselves, and at other times from the (contingent) proposition being converted; when, however, each of these occurs, and for what reason, we have shown. But if one proposition be assumed as universal, and the other particular, when the universal contingent is joined to the major extreme, whether it be affirmative or negative, but the particular is a simple affirmative de inesse, there will be a perfect