excluded middle

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Related to Law of excluded middle: Law of contradiction

excluded middle

n
(Logic) logic the principle that every proposition is either true or false, so that there is no third truth-value and no statements lack truth-value
References in periodicals archive ?
In De Interpretatione 6-9, Aristotle considers three logical principles: the principle of bivalence, the law of excluded middle, and the rule of contradictory pairs (according to which of any contradictory pair of statements, exactly one is true and the other false).
This statement of the law of excluded middle sounds straightforward enough, but then, what is an assertible?
Dummett points out that this view avoids the absurd consequence that no undecidable proposition is intelligible, but leads to rejection of the principle of bivalence and of the law of excluded middle and calls for a detailed explanation of what is meant by saying that a proposition can be justified.