In the early chapters of Mind and the World Order, Lewis develops a theory of meaning which has interesting points of similarity with that mentalistic or propositional theory of meaning which has been rejected by Quine, in Word and Object and elsewhere. There are also interesting similarities, however, between Lewis’ theory and Quine's own naturalistic theory. In this paper, I shall concentrate on one such similarity: namely, the analogy, noticed by Quine, between the predicament formulated in his own thesis of the indeterminacy of translation, and the “predicament of private worlds” in which Lewis’ theory of meaning is involved.

These analogous predicaments have a bearing on the problems of the commensurability of scientific theories and of objectivity in science in general; in fact, my primary motivation in attempting to explicate the analogy between Quine's theory of meaning and Lewis’ theory is to clear the way for an assessment of Quine's position on the problem of the objectivity of theories in science.