Our sense of who we are depends, in significant part, on our memories. And yet they’re not to be trusted. ‘What is selected as a personal memory,’ writes Professor of psychology and neuroscience Giuliana Mazzoni, ‘needs to fit the current idea that we have of ourselves.’

Dorian Deshauer, a psychiatrist and historian at the University of Toronto, told me, “Once you abandon the idea of the personal baseline, it becomes possible to think of emotional suffering as relapse—instead of something to be expected from an individual’s way of being in the world.”