Full Idea
It is not necessary that of every affirmation and opposite negation one should be true and the other false. For what holds for things that are does not hold for things that are not but may possibly be or not be.
Gist of Idea
It doesn't have to be the case that in opposed views one is true and the other false
Source
Aristotle (On Interpretation [c.330 BCE], 19a39)
Book Reference
Aristotle: 'Categories and De Interpretatione', ed/tr. Ackrill,J.R. [OUP 1963], p.53
A Reaction
Thus even if Bivalence holds, and the only truth-values are T and F, it doesn't follow that Excluded Middle holds, which says that every proposition must have one of those two values.