 But suppose we do hold, as Priest does, that the argument is valid. Generalising, we might think that if you are interested only in the truth about logical consequence, then it is never legitimate to ignore the meaning of some expression in an argument. If simplicity and conservativeness are of no concern, then you should not be appealing to Tarski-style interpretations in defining validity—since the whole point of such interpretations is to allow the meanings of certain expressions to vary. Better than any ‘interpretation’ would be a complete possible world (perhaps we can argue about which things are included in ‘all possible worlds’, but there might also be a correct answer to that question.) Hence many of the possible disambiguations of ‘case’ give us different false theories of validity. Those might be useful because they are simple and they approximate the true account, but since the logics they capture are not correct, this is a view on which no pluralism threatens. 