High Quality Content by WIKIPEDIA articles! In logic and mathematics, a logical value, also called a truth value, is a value indicating the relation of a proposition to truth. Search Wiktionary In classical logic, the truth values are true and false. Intuitionistic logic lacks a complete set of truth values because its semantics, the Brouwer-Heyting-Kolmogorov interpretation, is specified in terms of provability conditions, and not directly in terms of the truth of formulae. Multi-valued logics (such as fuzzy logic and relevance logic) allow for more than two truth values, possibly containing some internal structure.