Debate initiated by the Austrian philosopher Ludwig Wittgenstein (1889-1951) in his posthumous Philosophical Investigations.
This debate concerns the question of whether there could possibly exist a private language; that is, a language which is 'necessarily unteachable' because the meanings of words known by an individual are based on private and undemonstrable experiences of their referents.
Wittgenstein argued that the speaker of such a language could not, even in principle, check whether he was using such words correctly; from which it followed (he thought) that there would be no such thing as a correct, as against incorrect, use of such words, so that the speaker would not really be saying anything.
The soundness of the argument is disputed, but its importance is that words referring to immediate experiences (like 'pain') have been thought to have meaning in this way, by empiricists in particular. If Wittgenstein is right, such notions as the egocentric predicament and solipsism and many forms of skepticism become incoherent.
L Wittgenstein, Philosophical Investigations (1953), 243-315;
O R Jones, ed., The Private Language Argument (London, 1971)