Editing Truth (section)

==Folk beliefs==
The [[truth predicate]] "''P'' is true" has great practical value in human language, allowing ''efficient'' endorsement or impeaching of claims made by others, to emphasize the truth or falsity of a statement, or to enable various indirect ([[Gricean]]) conversational implications.<ref>{{cite book|last1=Scharp|first1=Kevin|title=Replacing truth|date=2013|publisher=Oxford Univ. Press|location=Oxford|isbn=978-0-19-965385-0|edition=First|chapter=6: What is the Use?}}</ref> Individuals or societies will sometime punish "false" statements to deter falsehoods;<ref>{{cite web|title=truth {{!}} philosophy and logic|url=https://www.britannica.com/topic/truth-philosophy-and-logic|website=Encyclopedia Britannica|access-date=28 July 2017|language=en|quote=Truth is important. Believing what is not true is apt to spoil a person's plans and may even cost him his life. Telling what is not true may result in legal and social penalties.|archive-date=5 June 2019|archive-url=https://web.archive.org/web/20190605223755/https://www.britannica.com/topic/truth-philosophy-and-logic|url-status=live}}</ref> the oldest surviving law text, the [[Code of Ur-Nammu]], lists penalties for false accusations of sorcery or adultery, as well as for committing [[perjury]] in court. Even four-year-old children can pass simple "[[Theory of mind#False-belief task|false belief]]" tests and successfully assess that another individual's belief diverges from reality in a specific way;<ref>Wellman, Henry M., David Cross, and Julanne Watson. "Meta‐analysis of theory‐of‐mind development: the truth about false belief." Child development 72.3 (2001): 655–684.</ref> by adulthood there are strong implicit intuitions about "truth" that form a "folk theory" of truth. These intuitions include:<ref>Lynch, Michael P. "Alethic functionalism and our folk theory of truth." Synthese 145.1 (2005): 29–43.</ref>
* Capture (''T''-in): If ''P'', then ''P'' is true
* Release (''T''-out): If ''P'' is true, then ''P''
* [[Law of noncontradiction|Noncontradiction]]: A statement cannot be both true and false
* Normativity: It is usually good to believe what is true
* False beliefs: The notion that believing a statement does not necessarily make it true

Like many folk theories, the folk theory of truth is useful in everyday life but, upon deep analysis, turns out to be technically self-contradictory; in particular, any [[formal system]] that fully obeys "capture and release" semantics for truth (also known as the ''[[T-schema]]''), and that also respects classical logic, is provably [[inconsistent]] and succumbs to the [[liar paradox]] or to a similar contradiction.<ref>Bueno, Otávio, and Mark Colyvan. "Logical non-apriorism and the law of non-contradiction." The law of non-contradiction: New philosophical essays (2004): 156–175.</ref>