This category is concerned with the life and works of Ludwig Wittgenstein. The Biography subcategory is for articles and sites concerned with the life of Wittgenstein, and his character. General Introductions contains material that attempts to give an broad introduction to Wittgenstein's thought. German Language Sites gives links to sites in the World/Deutsch hierarchy. On Certainty, Philosophical Investigations and Tractatus contain material principally concerned with the works by those names. Private Language Argument concerns work in the Philosophy of Language inspired by the passages of the Philosophical Investigations that puroprt to show that there can be no such thing as a private language. Reference contains links to online texts of works by Wittgenstein, bibliographies, quotations and links to online resources.