Theseus persuades his father to allow him to go to Crete, with the aim of killing the Minotaur. And if he kills the creature he will signal his success by flying a white sail on the return journey.

But why? Theseus, the Greek hero of myth who defeated the Minotaur and navigated the perilous Labyrinth, is renowned for his ship. Philosophers have been fascinated by it for ages. Plutarch tells ...