Rudolf Carnap's Principle of Tolerance is an early formulation of the idea of Logical Pluralism:
In Logic, there are no morals. Everyone is at liberty to build his own logic, i.e. his own form of language as he wishes.
But is the logical validity of an argument just a matter of language choice? And if so, is this really a pluralism about logic, not rather a pluralism about languages?
Contemporary Logical Pluralism also insists that there is more than one correct logic. Classical, intuitionist, and relevent logic, as well as a number of other logics, all correctly govern our reasoning within a given language, but apply to different cases. Can we make sense of genuinely different, but equally good logical consequence relations?
