In 2011, I was invited to guest edit the Christmas double issue of the New Statesman. I enjoyed the experience, which involved a visit to Christopher Hitchens in Texas to conduct what turned out to be his last interview. I didn’t ask him, “What is a woman?” In 2011, it wouldn’t have occurred to anyone to ask such a daft question. Today it is hurled at embarrassed and perplexed politicians, in tones that are challenging to the point of belligerence. It isn’t hard to imagine Hitchens’ response if he could be asked it today.

My main contribution to that Christmas issue was a long essay on “The tyranny of the discontinuous mind”. Everywhere you look, smooth continua are gratuitously carved into discrete categories. Social scientists count how many people lie below “the poverty line”, as though there really were a boundary, instead of a continuum measured in real income. “Pro-life” and pro-choice advocates fret about the moment in embryology when personhood begins, instead of recognising the reality, which is a smooth ascent from zygotehood. An American might be called “black”, even if seven eighths of his ancestors were white.