Abstract

Many arguments are affected by context sensitivity, because they include sentences that have different truth conditions in different contexts. Therefore, it is natural to think that a general criterion for evaluating arguments must take context sensitivity into account. One way to give substance to that thought is provided by the definition of validity offered by David Kaplan within his theory of indexicals. However, the route indicated by Kaplan is hindered by a problem whose importance is often underestimated. This paper explores a different route, and outlines a definition of validity that does not run into that problem. Its moral is that Kaplan's definition is not the only plausible definition. This is not to say that the definition outlined is the only plausible definition or that it is correct in some absolute sense. There might be equally important problems with it that the paper does not take into account. But until such problems are found and brought up, the departure from Kaplan's route remains a viable option.