Truism

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