Truth
theory of truth · correspondence theory
What it is for a claim to correspond to, cohere with, or work in reality.
In practice
A report is internally consistent and every number ties out. Coherence has been established; whether it corresponds to what happened is a separate check, and only one of the two can be done from inside the document.
The common mistake
Assuming a theory of truth tells you how to find truths. These theories say what truth consists in; the methods for finding it belong to epistemology.
Truth is the property a statement has when it says how things are. Every theory of truth tries to explain what that amounts to without simply repeating the word.
The main theories
The correspondence theory holds that a statement is true when it matches a fact in the world. "Snow is white" is true when snow is white. This fits ordinary usage and runs into difficulty specifying what a fact is and what matching means for claims about numbers, morals or the future.
The coherence theory holds that truth consists in fitting into a consistent system of beliefs. It handles abstract domains well and faces the objection that a well-built fiction is internally coherent.
Pragmatist theories, developed by William James and John Dewey, treat truth as what survives inquiry — the belief that keeps working as evidence accumulates. Critics object that this describes the marks of truth rather than what truth is.
Deflationary theories argue that the concept carries less weight than it appears to. Saying "it is true that snow is white" asserts only that snow is white, so truth is a device for endorsement rather than a substantial property.
The liar
"This sentence is false" is true if false and false if true. The liar paradox is not a curiosity: any language rich enough to talk about its own sentences generates it. Alfred Tarski's response in 1933 was to separate the language being described from the language doing the describing, which blocks the paradox and implies that no sufficiently rich language can consistently contain its own truth predicate.
Truth connects to knowledge, which requires it, and to skepticism, which asks how we could ever tell we have reached it.
Concept web
Open the full webQuestions
What is the correspondence theory of truth?
The view that a statement is true when it corresponds to how things actually are. It matches ordinary usage closely and faces difficulty explaining what facts are and how correspondence works for abstract claims.
What is the liar paradox?
The sentence 'this sentence is false' is true if it is false and false if it is true. It shows that languages able to describe their own sentences can generate contradictions.
Is truth relative?
Philosophers distinguish relative standards of evidence from relative truth. That different communities accept different claims is uncontroversial; that a claim can be true for one and false for another, in the same sense, is much harder to defend.