Ludwig Wittgenstein (1889–1951) is unusual because his early and later work seem almost like two different philosophical projects — and the later project attacks the temptation to build theories much like the earlier one.

Early Wittgenstein

The Tractatus Logico-Philosophicus treats meaningful propositions as having logical structure capable of picturing possible facts. The limits of meaningful language matter deeply: some things philosophers try to say may instead show themselves in the structure of language/world.

Later Wittgenstein

The Philosophical Investigations rejects the hunt for one hidden essence of meaning.

Big idea: For many words, meaning is use within human practices — “language-games” embedded in broader “forms of life.”

The word “game,” for example, may not have one feature shared by every possible game. Instead there are overlapping family resemblances. Philosophical confusion often appears when we assume every noun must name one essence or when words are torn from the practices that give them a role.

The famous private-language argument challenges the idea of a language whose terms refer to inherently private sensations in a way only one person could in principle understand/check. Meaning requires standards of use that cannot be reduced to an individual's uncheckable inner act.

“Meaning is use” should not be simplified into “words mean whatever people want.” Uses are embedded in shared practices, norms, contexts, and forms of life.