to be from necessity, when it is, and simply to be from necessity, and in like manner as to non-being. There is the same reasoning also in the case or contradiction; to be or not to be is necessary for every thing, also that it shall, or shall not be, yet it is not requisite to speak of each separately, but I say, for instance, that it is necessary for a naval action to occur or not occur to-morrow, yet it is not necessary that there should be a naval action to-morrow, nor that there should not be; it is necessary, however, that it should either be or not be. Wherefore, since assertions and things are similarly true, it is evident that things which so subsist, as that whatever have happened, the contraries also were possible, it is necessary that contradiction should subsist in the same manner, which happens to those things which are not always, or which not always, are not. For of these, one part of the contradiction must necessarily be true or false, not indeed this or that, but just as it may happen, and one must be the rather true, yet not already true nor false; so that it is evidently not necessary that of every affirmation and negation of opposites, one should be true, but the other false; for it does not happen in the same manner with things which are not, but which either may or may not be, as with things which are, but it happens as we have said.
