I was in my early twenties when I was introduced to Sir Karl Popper. The great philosopher was by then very old and very deaf. Even if a question was shouted into his ear, he wouldn’t always hear it and might answer about something else. Nonethless, I was lucky enough to hear him say many wise things that have stayed with me ever since.

These are the most important things I learnt from Popper: a worthwhile statement should be capable of being falsified. And that we only make intellectual progress by testing our theories and adapting them. We should not be afraid of being wrong but we should be afraid of persisting in error.

These lessons seem pertinent as the prospect of a no-deal Brexit