In the early "Tractatus Logico-Philosophicus" (1921), Wittgenstein argued that meaningful propositions picture possible states of affairs by sharing logical form with what they represent, concluding that ethics, metaphysics, and philosophy itself lie beyond what can be meaningfully said. In the posthumous "Philosophical Investigations" (1953) he repudiated much of this picture theory, arguing instead that meaning arises from a word's use within rule-governed social practices he called "language games," and that many philosophical problems dissolve once ordinary language use is properly understood.
Intellectual setting
The "Tractatus" directly shaped the Vienna Circle's logical positivism even as Wittgenstein later rejected many of its interpretations, and the radically different "Philosophical Investigations," developed during his return to Cambridge in the 1930s-40s, launched the ordinary language philosophy movement centered there and at Oxford.
Key ideas
The picture theory of meaning
In the "Tractatus," Wittgenstein argued that a meaningful proposition functions as a logical picture of a possible fact, sharing its logical form with what it depicts, and that what can be pictured and stated meaningfully is strictly limited, leaving ethics and the nature of philosophy itself literally unsayable.
Language games and meaning as use
In the "Philosophical Investigations," Wittgenstein argued that a word's meaning is constituted by its use within a rule-governed social practice or "language game" embedded in a form of life, not by a fixed picturing or naming relation, and that philosophical confusions often arise from misreading how language actually works.
Legacy
Wittgenstein is regarded as one of the most influential philosophers of the twentieth century in two distinct phases; his early work shaped logical positivism and his later work shaped ordinary language philosophy, philosophy of mind, and philosophy of language across subsequent analytic philosophy.