Once, when we humans reflected on what made us special, we latched on to those qualities that distinguished us from the rest of creation. We were smarter, more rational, more cognitively capable. The philosopher Joseph de Maistre, for example, proposed that ‘the concept of number is the obvious distinction between beast and man’. More recently, with the onrush of the digital age, we have come to feel less confident in our mental powers. We may understand numbers better than other beasts, but our phones can carry out arithmetic calculations at inconceivable speeds and beat the brainiest among us at chess.