Editing Many-valued logic (section)

{{Short description|Propositional calculus in which there are more than two truth values}}
{{Use mdy dates|date=November 2022}}

'''Many-valued logic''' (also '''multi-''' or '''multiple-valued logic''') is a [[propositional calculus]] in which there are more than two [[truth value]]s. Traditionally, in [[Aristotle]]'s [[Term logic|logical calculus]], there were only two possible values (i.e., "true" and "false") for any [[proposition]]. Classical [[two-valued logic]] may be extended to '''''n''-valued logic''' for ''n'' greater than 2. Those most popular in the literature are [[Three-valued logic|three-valued]] (e.g., [[Jan Łukasiewicz|Łukasiewicz's]] and [[Stephen Cole Kleene|Kleene's]], which accept the values "true", "false", and "unknown"), [[four-valued logic|four-valued]], [[nine-valued logic|nine-valued]], the [[finite-valued logic|finite-valued]] (finitely-many valued) with more than three values, and the [[infinite-valued logic|infinite-valued]] (infinitely-many-valued), such as [[fuzzy logic]] and [[probabilistic logic|probability logic]].