Book 11
16
Thus from these considerations it is obvious that opposite statements cannot be true of the same thing at one time; nor can contrary statements, since every contrariety involves privation. This is clear if we reduce the formulae of contraries to their first principles.Cf. Aristot. Met. 4.6.10, 11.
16
Similarly no middle term can be predicated of one and the same thing of which one of the contraries is predicated.Cf. Aristot. Met. 4.7 where, however, the point which is proved is that there can be no intermediate between contradictories.
17
If, when the subject is white, we say that it is neither white nor black, we shall be in error; for it follows that it is and is not white, because the first of the two terms in the complex statement will be true of the subject, and this is the contradictory of white.
17
Thus we cannot be right in holding the views either of HeraclitusCf. Aristot. Met. 11.5.8 or of Anaxagoras.Cf. Aristot. Met. 4.7.8-8.5
18
If we could, it would follow that contraries are predicable of the same subject; for when heAnaxagoras. What he really meant was that even the sweetest things contain some bitter particles. Cf. Anaxagoras Fr. 11 (Diels); Burnet, E.G.P. 129. says that in everything there is a part of everything, he means that nothing is sweet any more than it is bitter, and similarly with any of the other pairs of contraries; that is, if everything is present in everything not merely potentially but actually and in differentiation.
19
Similarly all statements cannot be false, nor all true. Among many other difficulties which might be adduced as involved by this supposition there is the objection that if all statements were false, not even this proposition itself would be true; while if they were all true it would not be false to say that they are all false.
