The picture theory of language, also known as the picture theory of meaning, is a theory of linguistic reference and meaning articulated by Ludwig Wittgenstein in the Tractatus Logico-Philosophicus.
Wittgenstein suggested that a meaningful proposition pictured a state of affairs or atomic fact.
The picture theory of meaning states that statements are meaningful if, and only if, they can be defined or pictured in the real world.
Wittgenstein's later investigations laid out in the First Part of Philosophical Investigations refuted and replaced his earlier picture-based theory with a use theory of meaning.
However, the second psychology-focused Part of Philosophical Investigations employs the concept as a metaphor for human psychology.