Private Language Argument

The private language argument is Wittgenstein's argument in the Philosophical Investigations (§§ 243–315) against the intelligibility of a language whose terms could be understood in principle only by a single person — most pressingly, a language for one's own inner sensations (pains, after-images, felt qualities). The argument: suppose I try to establish a name for a recurring inner sensation by concentrating on it and saying 'I call this S.' What criterion ensures that I apply 'S' correctly on subsequent occasions? The sensation is not publicly observable, so no external correction is possible. But without the possibility of correction, there is no distinction between correctly applying 'S' and merely seeming to apply it correctly — which means there is no rule being followed and therefore no genuine language. The argument is not a denial that inner states exist; it is a denial that inner ostension (mental pointing at a private object) can establish the meaning of a term. Meaning requires public practice, checkable use, the possibility of being wrong. The private language argument is the most technically demanding and debated section of the Investigations and underlies Wittgenstein's critique of Cartesian inner theater — the picture of the mind as a private arena to which only the owner has access, populated by objects that cannot in principle be publicly identified or verified.