Law or Principle of Bivalence

Discipline: Philosophy

Theory that every proposition is either true or false.

Possible objections are of two kinds.

First, can we decide what counts as a proposition in the relevant sense?

Second, might not the principle fail for some presumably genuine propositions; for example, 'Jones was brave' (where Jones died peacefully after a life entirely devoid of danger)?

The law of bivalence is not necessarily the same as that of excluded middle.

Source:
MAE Dummett, 'Truth', Proceedings of the Aristotelian Society (1958-59)