The Discontinuous Mind

How many of us lie below the stupidity line? How many runners exceed the fast line? How many Oxford undergraduates lie above the first-class line? Yes, we in universities do it too. Examination performance, like most measures of human ability or achievement, is a continuous variable whose frequency distribution is bell-shaped. Yet British universities insist on publishing a class list, in which a minority of students receive first-class degrees, rather a lot obtain seconds (nowadays subdivided into upper and lower seconds), and a few get thirds. That might make sense if the distribution had several peaks with more-or-less shallow valleys in between, but it doesn’t. Anybody who has ever marked an exam knows that the distribution is unimodal. And the bottom of one class is separated from the top of the class below by a small fraction of the distance that separates it from the top of its own class. This fact alone points to a deep unfairness in the system of discontinuous classification.

These examples illustrate the ubiquity of what I am calling the discontinuous mind. It can probably be traced to the ‘essentialism’ of Plato – one of the more pernicious ideas in all history. At what precise moment during development does an embryo become a ‘person’? Only a mind infected with essentialism would ask such a question. An embryo develops gradually from single-celled zygote to newborn baby, and there’s no instant when ‘personhood’ should be deemed to have burst on the scene. The world is divided into those who get this truth, and those who wail: ‘But there has to be some moment when the fetus becomes human. Doesn’t there?’ No, there really doesn’t, any more than there has to be a day when a middle-aged person becomes old. The discontinuous mind can lead people to describe abortion as murder, even when the embryo has no more brain than a worm. And they may therefore feel righteously justified in committing real murder against a doctor – a thinking, feeling, sentient adult, with a loving family to mourn her.

Paleontologists may argue passionately about whether a particular fossil is, say, Australopithecus or Homo. But, given that the second evolved gradually from the first, there must have existed individuals who were intermediate. It is essentialist folly to insist on shoehorning your fossil into one genus or the other. There never was an Australopithecus mother who gave birth to a Homo child. Quarrelling fiercely about whether a fossil is ‘really’ Australopithecus or Homo is like having a heated argument over whether George is ‘tall’. He’s five foot ten, doesn’t that tell you everything you need to know?

Every creature who ever lived belonged to the same species as its mother. If a time machine could serve up your 200 million greats-grandfather, you would eat him with sauce tartare and a slice of lemon. He was a fish. Yet you are connected to him by an unbroken line of intermediate ancestors, every one of whom belonged to the same species as its parents and its children. ‘I’ve danced with a man who’s danced with a girl who’s danced with the Prince of Wales,’ as the song goes. I could mate with a woman, who could mate with a man, who could mate with a woman who . . . after a sufficient number of steps . . . could mate with an ancestral fish, and produce fertile offspring. It is only the discontinuous mind that insists on drawing a line between a species and the ancestral species that birthed it. Evolutionary change is gradual: there never was a line between any species and its evolutionary precursor.

- Richard Dawkins