And boy did they hate her. Not just Mill’s friends then, but his biographers now. The battle over whether she had any input into his work at all; or was just a pedestrian and controlling bitch — rages a century and a half later. Why? Was Mill not smart enough to know? Is his evidence insufficient? Did he not tell us she was the most important influence on him ever? Did he not move into a small hut by her grave in Avignon to be near her even in her death?

There is an interesting angle to pursue: after they met and fell in love, they broke off all meetings — perhaps they were too shocked by the inappropriateness of what they were feeling — but, from afar, they exchanged essays on love and marriage, which were, apparently, their way to try to deal with the problem of love and marriage in conflict. Only after the essays have been exchanged, and digested, and, one imagines, discussed, and after Mill made his peace with her husband, did they go off to Paris together. Where, apparently, they experienced “inexpressible joy”.

But the biographers… what is it? Why do some women attract such overpowering and irrational hate?

Essays on Sex Equality, By John Stuart Mill and Harriet Taylor Mill, edited and with an introductory essay by Alice Rossi