Truth Preservation in Any Context

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.