 It might not be obvious to a modern reader why that is the case. Why could we not be tolerant of alternative languages, which seems only sensible, without thereby committing ourselves to being tolerant of alternative logics? Moreover, logicians who disagree about which sentential logic is correct (e.g., classical or intuitionist) seem to be able to use the same language (containing ∧, →, ¬, etc.) even while they suppose that one logic is right for that language, and one logic wrong. If that position is coherent, then one side must have made a mistake after all, implying they were not really ‘at liberty to build their own logic.’ 