Fratenité – the idea of belonging to a community – is fundamental to human nature. We are social animals. But belonging – like the other social instincts – has both positive and negative aspects. It can be expressed as cosy communalism or hatred of outsiders.

‘Identity’ politics have become ever more important in recent years – feeling populist nationalism in the USA and UK or Islamic fundamentalism. These are both examples of this social instinct getting out of control.