When I tell people about it they either look blank or say: ‘Oh! You mean you have that too?’ But it isn’t a bond between us, not a secret, just a peculiarity, an anomaly, perhaps as random a feature of our minds as the ability to roll one’s tongue is of our bodies. It solves no problem, conveys no insight, and yet leaves me with an impression of significance. It has an aftertaste, but no taste. That impression, that aftertaste, may be its empty secret: it may be a tiny glitch in the p...