Wrapped in his fantasy world of a Labour party ruling the country in accordance with the diktats of those of its members who support him, Jeremy Corbyn reminds one of Plato’s image of humans trapped in a cave, able only to see the wall in front of them. Behind them, at the opposite end of the cave, is a fire, and in front of that, a puppet show. The shadows of those puppets, cavorting on the wall in front of him, are man’s reality. And Corbyn’s. His MPs are right to want a party connected to the real world, but is a leadership battle the right way to go about it?

The contest should be a purely rhetorical one, though Corbyn’s followers will not hesitate to use force instead. So much for their understanding of democracy, which ancient Greeks invented in order to defuse violence and allow decisions to be reached peacefully, by argument, among the whole citizen body, in assembly, and not a self-selected few.

The first document we know of that attempted to create a comprehensive manual for the budding rhêtor (Latin orâtor) in assembly was Aristotle’s Art of Rhetoric (4th C bc). Its purpose was to help him find the logical arguments, based on evidence and probability, that would display his trustworthiness, with the best interests of people at heart, while striking the right emotional notes among his listeners.

The key to success was what the Romans were to call inventio — the business of actually finding those arguments. That was where the orator’s skill lay. The Art of Rhetoric is full of examples of such inventio, both logical and psychological. But there was a catch: all your best efforts would be wasted if the conditions were not favourable.

So are they? At present, evidence suggests it does not look good for the challenger. In that case, the odds must be on Labour remaining in La-La-bour land, admiring the shadow puppets, for many years to come. Still, the extreme left is congenitally anarchic and always implodes. Patient endurance will reap its own rewards.