  ‘Cronus’ was his nickname, said to have been inherited from his teacher Apollonius Cronus. It meant roughly ‘old fogey’. But Diodorus, far from being an old fogey, comes over as a rather flamboyant and non-traditional figure. To prove a point about the non-natural character of language (see 3 below), he renamed one of his slaves ‘Allamēn’ (not a randomly chosen sound but a Greek conjunction favoured by logicians like Diodorus for introducing the minor premise of a syllogism, ‘But now …’). And in defiance of the male-centred customs of contemporary philosophical education, he trained all five of his daughters in dialectic. His work in logic was so well known that, according to the Alexandrian poet Callimachus, even the crows on the rooftops recognized his wisdom, cawing out Diodorean questions about the soundness of a conditional. And his celebrated Master Argument, with which he sought to establish his modal definitions, was said to be hotly debated even at dinner parties.