Alfred Ayer – known professionally as A.J. Ayer and privately as ‘Freddie’ – died in 1989 and was a philosopher who once had a run-in with the heavyweight boxer Mike Tyson at a party.

The pugilist was making unwelcome advances to a female guest when Ayer told him to stop. ‘Do you know who the **** I am? I’m the heavyweight champion of the world,’ said Tyson, to which Ayer responded: ‘And I am the former Wykeham Professor of Logic.’ He could have added that he was also the author of Language, Truth, and Logic (1936), had served in the SOE during the war and MI6 to boot, and had been married four times (to three women). As a philosopher Ayer propounded the ‘verification principle’, which maintains that only statements that are empirically verifiable are cognitively meaningful, or else they are tautologies.