<philosophy of science, epistemology, logic> supposition that every proposition must be either true or false. The status of this supposition is controversial, especially with respect to future propositions about human action. Thus, for example, if "I will vacuum the carpet tomorrow." were regarded as already true (or false) today, it would seem that I cannot freely choose whether or not to clean. Note the difference between bivalence and excluded middle. Recommended Reading: Ermanno Bencivenga, Logic, Bivalence and Denotation (Ridgeview, 1991).
[A Dictionary of Philosophical Terms and Names]
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