"What would be the consequences for the theory of truth, asked one worried logician,’… of the adoption of a non-standard system’? Another, observing systems of modal logic, observed: ‘One gets an uneasy feeling as one discerns and studies more of the systems belonging to this family that it is literally a family, and has the power of reproducing and multiplying, proliferating new systems [of logic] without limit.’ In a world in which even the rules of logic shifted and disintegrated, it is not surprising that modern times did not develop in ways the generation of 1920 would have considered ‘logical’."