Page:O. F. Owen's Organon of Aristotle Vol. 1 (1853).djvu/210

 versally, as far as regards the setting out of the terms; the like also happens in negatives. We see then that if the conclusion is false, those things from which the reasoning proceeds, must either all or some of them be false; but when it (the conclusion) is true, that there is no necessity, either that a certain thing, or that all things, should be true; but that it is possible, when nothing in the syllogism is true, the conclusion should, nevertheless, be true, yet not of necessity. The reason of this however is, that when two things so subsist with relation to each other, that the existence of the one necessarily follows from that of the other, if the one does not exist, neither will the other be, but if it exists that it is not necessary that the other should be. If however the same thing exists, and does not exist, it is impossible that there should of necessity be the same (consequent); I mean, as if A being white, B should necessarily be great, and A not being white, that B is necessarily great, for when this thing A being white, it is necessary that this thing B should be great, but B being great, C is not white, if A is white, it is necessary that C should not be white. Also when there are two things, if one is, the other must necessarily be, but this not