England is currently in the middle of a heatwave (if you’re from a tropical country, try not to laugh). The air is hot, still and oppressive, and I feel like I’m stuck in a Tennessee Williams play. I wish I had a fan but, of course, all of the shops are out of fans. The smart move would have been to buy a fan in the middle of winter, when they were readily available. The fan would have been useless for months, neither giving me benefits not inconveniencing me. But when the environment changed and a cooling device suddenly became useful, I’d be laughing.

A lot of evolutionary biologists are coming round to the same idea. We’re used to the idea