truthcondition

Truth-condition, or truth conditions, is a concept in philosophy of language and formal semantics that describes the conditions under which a proposition or sentence would be true. In truth-conditional theories, the meaning of a sentence is defined by the set of circumstances under which it would hold true. A simple example: the sentence “The grass is green” is true in a world if and only if, in that world, the grass is green. For more complex sentences, truth conditions are determined compositionally from the truth conditions of their parts and their syntactic form.

Historically, the idea traces to the Fregean program of linking meaning to truth values and to the development of formal truth theories in the 20th century by logicians such as Tarski, who provided rigorous definitions of truth for formal languages. In modern linguistics and philosophy, truth-conditional semantics often uses possible-world or model-theoretic frameworks, where truth conditions are evaluated relative to a given possible world or interpretation.

Truth conditions are central to many linguistic analyses, including phenomena such as quantification, conditionals, and indexicals. For instance, the truth conditions of “It is raining” depend on the actual weather at the time and place of utterance, while “I am here now” shifts with context. Critics argue that not all aspects of meaning—such as context sensitivity, presupposition, or speech acts—are captured solely by truth conditions, suggesting that meaning can extend beyond truth-conditional content.

See also truth-conditional semantics, possible-world semantics, and model theory.