Creating a safe distance between people is easier out of town. Once we had contact with someone across the other side of the river, who we could barely see, who’d noticed us with binoculars and waved. Thoreau claims people, like nations, benefit from having ‘considerable neutral ground’ between them (in ‘Walden’, 1854). He found it a ‘luxury’ to talk with a neighbour across a pond.

It makes you think, when you’re lucky enough to be out and about, what sort of distance from other people is just right. Two metres, they say now.

I’m judging it all the time. Would an extra metre feel better? At what point do you lose the feeling of connection with someone? In a supermarket queue two metres never feels quite enough.

Living in his small hut in the woods Thoreau wondered how much space we need between us. There was no room to entertain people as a group – he was glad about that – and he decided to have only two chairs. The issue for him was getting these chairs far enough apart.

Distance, he explains, gives space for thought. You need room for thoughts to move around a bit before delivering them to the person you are talking with. If all you want to do is talk a lot without thinking, then you can be as close you like. But if you want to speak thoughtfully you need to be further apart, not to feel the pressure – both metaphysical and physical – from the other person.

Talking, he wrote, is like throwing stones into calm water. If two people speak too loudly, or are too close, it’s like throwing stones into calm water so close that they break each other’s outward moving ripples. More distance allows your thoughts to spread without disturbance.