Abstract

Tarski's equivalence, as he allows, applies only roughly to assertions in ordinary language. Some of the relevant exceptions are of merely grammatical importance but others leave scope for interesting metaphysical pronouncements on science, mathematics and other fields of assertion. To understand these latter exceptions is to gain insight into Baylis' and Lukasiewicz' views on the question "Are some Propositions neither True nor False?" (this journal, 1936). From different standpoints each is right and each is wrong. This comment also applies to some later contributions to their controversy