The essays collected here explore a fundamental contrast between two overall visions of language and its availability to self-examination. They can be characterized as "language as the universal medium" and "language as calculus" (or the model-theoretical view). The former normally includes the ineffability of semantics and a one-world ontology. This contrast has dominated twentieth-century philosophy but has scarcely been acknowledged before. Philosophers examined here from the vantage point of the contrast include Peirce, Frege, Wittgenstein, Carnap, Quine, Husserl and Heidegger. Tarski's famous result concerning the indefinability of truth seems to decide the issue in favor of the universalists. Hintikka nevertheless shows that Tarski's result is inconclusive and that truth can in fact be defined in languages which are in certain respects comparable to ordinary language. This unique volume is a must for every contemporary philosopher and for everyone interested in the semantics of our language.