 There is, however, another more general problem that affects Davidson’s appropriation of Tarski. While Tarski uses the notion of sameness of meaning, through the notion of translation, as the means to provide a definition of truth – one of the requirements of Convention T is that the sentence on the right hand side of a Tarskian T-sentence be a translation of the sentence on the left – Davidson aims to use truth to provide an account of meaning. But in that case it seems that he needs some other way to constrain the formation of T-sentences so as to ensure that they do indeed deliver correct specifications of what sentences mean. This problem is readily illustrated by the question of how we are to rule out T-sentences of the form “‘Schnee ist weiss’ is true if and only if grass is green.” Since the biconditional ‘if and only if’ ensures only that the sentence named on the left will have the same truth value as the sentence on the right, so it would seem to allow us to make any substitution of sentences on the right so long as their truth value is identical to that on the left. In one respect this problem is met by simply insisting on the way in which T-sentences must be seen as theorems generated by a theory of meaning that is adequate to the language in question as a whole (see ‘Truth and Meaning’). Since the meaning of particular expressions will not be independent of the meaning of other expressions (in virtue of the commitment to compositionality the meanings of all sentences must be generated on the same finite base), so a theory that generates problematic results in respect of one expression can be expected to generate problematic results elsewhere, and, in particular, to also generate results that do not meet the requirements of Convention T. This problem can also be seen, however, as closely related to another important point of difference between a Tarskian truth theory and a Davidsonian theory of meaning: a theory of meaning for a natural language must be an empirical theory – it is, indeed, a theory that ought to apply to actual linguistic behaviour – and as such it ought to be empirically verifiable. Satisfaction of the requirement that a theory of meaning be adequate as an empirical theory, and so that it be adequate to the actual behaviour of speakers, will also ensure tighter constraints (if such are needed) on the formation of T-sentences. Indeed, Davidson is not only quite explicit in emphasising the empirical character of a theory of meaning, but he also offers a detailed account that both explains how such a theory might be developed and specifies the nature of the evidence on which it must be based.