The word truth has a variety of meanings, from honesty, good faith, and sincerity in general, to agreement with fact or reality in particular. The term has no single definition about which a majority of professional philosophers and scholars agree, and various theories of truth continue to be debated. There are differing claims on such questions as what constitutes truth; what things are truthbearers capable of being true or false; how to define and identify truth; the roles that revealed and acquired knowledge play; and whether truth is subjective, relative, objective, or absolute. This article introduces the various perspectives and claims, both today and throughout history.

Nomenclature and etymology

see: Aletheia The English word truth is from Old English tríewþ, tréowþ, trýwþ, Middle English trewþe, cognate to Old High German triuwida, Old Norse tryggð. Like troth, it is a -th nominalisation of the adjective true (Old English tréowe).

The English word true is from Old English (West Saxon) (ge)tríewe, tréowe, cognate to Old Saxon (gi)trûui, Old High German (ga)triuwu (Modern German treu "faithful"), Old Norse tryggr, Gothic triggws, all from a Proto-Germanic *trewwj- "having good faith". Old Norse lang: trú, "faith, word of honour; religious faith, belief" (archaic English troth "loyalty, honesty, good faith", compare lang: Ásatrú).

Thus, 'truth' involves both the quality of "faithfulness, fidelity, loyalty, sincerity, veracity", and that of "agreement with fact or reality", in Anglo-Saxon expressed by sōþ.

All Germanic languages besides English have introduced a terminological distinction between truth "fidelity" and truth "factuality". To express "factuality", North Germanic opted for nouns derived from sanna "to assert, affirm", while continental West Germanic (German and Dutch) opted for continuations of wâra "faith, trust, pact" (cognate to Slavic věra "(religious) faith", but influenced by Latin verus). Romance languages use terms following the Latin veritas, while the Greek aletheia and Slavic pravda have separate etymological origins.

The major theories of truth

The question of what is a proper basis for deciding how words, symbols, ideas and beliefs may properly be considered true, whether by a single person or an entire society, is dealt with by the five major substantive theories introduced below. Each theory presents perspectives that are widely shared by published scholars. There also have more recently arisen "deflationary" or "minimalist" theories of truth based on the idea that the application of a term like true to a statement does not assert anything significant about it, for instance, anything about its nature, but that the label truth is a tool of discourse used to express agreement, to emphasize claims, or to form certain types of generalizations.