The seventh-century BC farmer-poet Hesiod reports that the Muses said to him, ‘We know how to speak many falsehoods which look like the truth, but we also know how to speak the truth when we want to.’ The problem mere mortals face is deciding which is which, especially in situations where evidence is lacking. Plausibility is the best we can do unless new evidence emerges. For example, it used to be thought that death by hemlock was rather gruesome – spasms, choking, vomiting and so on. So Plato’s depiction of the untroubled death of Socrates was taken to be Plato’s effort to maintain his image of a Socrates who could rise above mere physical discomfort. But now we know that Conium maculatum, the species of hemlock found on the slopes of Mt Hymettus, is not especially violent, but induces a gradual paralysis that leads to asphyxiation. So Plato’s depiction of Socrates’ peaceful passing – in which Socrates cracked jokes about making an offering to Asclepius, the god of healing – was in fact accurate. How much else is accurate, however, about Socrates is a matter of intense debate, especially the reasons for his trial and execution in 399 BC.

About the only thing we can report for certain about it is the precise wording of the charge, recorded by a later historian who took it from the Athenian archives: ‘Socrates is guilty of not acknowledging the gods the city acknowledges, and of introducing other new divinities. He is also