 According to Carnap then, the right way to specify a language is to pick some expressions, and then give the rules of inference for them. It is this specification which gives the expressions their meanings, and so, first, there is no question of their being the wrong rules for the expressions—everybody is at liberty to build his own logic, to choose whatever rules he likes—and second, to be tolerant about language choice is already to be tolerant about choice of logic—for languages so-conceived come with different logics already ‘built in.’ 