TruthConditions

Truthconditions are the conditions under which a sentence or proposition is true. In philosophy of language and formal semantics, a truth-conditional account of meaning holds that the content of a sentence consists of its truth conditions—the states of affairs or models in which the sentence would be true. A sentence is true only if the actual world (or the relevant model or possible-world) satisfies those conditions.

In formal work, truth conditions are often expressed using truth-conditional clauses or biconditionals. For example, a declarative sentence such as “Snow is white” is true in a world or model exactly when snow is white there. More generally, listeners or readers extract from a sentence the conditions that would make it true, and these conditions guide interpretation and inference.

Possible-world and model-theoretic approaches extend the idea. A sentence containing indices or variables is evaluated relative to a world and an assignment of values to variables; the sentence is true there if the interpretation in that world satisfies it. Contextual features, such as indexicals and demonstratives, can affect the relevant truth conditions, since different worlds or contexts may yield different truth values.

Truth-conditional theories have been foundational in semantics and linguistics, influencing the analysis of reference, composition, and the logic of language. They also face criticisms, notably that some aspects of meaning (such as evaluative or expressive content) may not be reducible to truth conditions.