The philosophy of Ludwig Wittgenstein is particularly well suited as a forum for discussion of current philosophical questions. In this context, we should not only consider the Wittgenstein of the Philosophical Investigations, who is now extensively quoted in linguistic and social science matters, but also the Wittgenstein of the Tractatus logico-philosophicus (Tractatus), where—as shall be shown—a theory of language as a self-referential system is established, which in part exhibits features of so-called Radical Constructivism and (with a view to the Philosophical Investigations) heralds the postmodern problem awareness of the "heterogeneity of language games." The Tractatus demonstrates that the "project of modernity"—to legitimize language and reality by recourse to a universal language system—fails, must fail from within. As a supposedly universal system, this language system is immune to external objections; it would have the omnipotence to define what is meaningful and valuable. However, it becomes entangled in internal contradictions when it attempts to do so, i.e., when it tries to explicate and legitimize its own system as universal. The alternative that the Tractatus leaves behind is: either to remain silent or to abandon the assumption of a universal language system. The following traces the argumentative development from the Tractatus to the Philosophical Investigations, where this assumption is given up and a novel practice of legitimation is designed.
