Ethical Corruption & Non-Rational Belief in _Republic_ Books 8 to 10

Republic Book 10’s account of corruption – of how a person declines from a better to a worse state of character – is rarely compared with the account of corruption in Books 8 and 9. This paper argues that Plato intended Book 10 to shed light on the earlier discussion. Non-rational beliefs play a prominent role in Books 8 and 9’s account of corruption, but within metaphors that are indecipherable without drawing on the more detailed and literal account developed in Book 10, which examines the corruption of a certain ‘decent’ (epieikēs) character. I offer an account of the cognitive side of corruption across all three books, guided by the task of explaining the puzzling attributions of non-rational belief in Books 8 and 9.