Main Page | See live article | Alphabetical index A truism is a claim which is so obvious or self-evident as to be hardly worth mentioning, except as a reminder or as a rhetorical or literary device. A proposition may be a truism even if it is not a tautology, a restatement of a definition, or a theorem derived from axioms that are generally held to be true. In fact, some would say that such analytic propositions should not be regarded as truisms. Often the word is used to disguise the fact that a proposition is really just a half-truth or an opinion, especially in rhetoric. Examples in logic, A and ~A being a contradiction is a truism. in set theory, a branch of abstract mathematics, A intersection ~A being the null set is a truism. in English: "It's a truism that prevention is better than cure." See also Synthetic proposition aphorism axiom banality cliché commonplace dictum fact gospel maxim moral This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.