Let’s say there’s another pandemic. This time, a lethal disease spreads through contact with other people’s fecal matter. Precision toilet cleaning becomes a matter of life and death. In the wake of this pandemic, an aptitude test—call it the T.I.Q.—is developed to measure one’s ability to rotate brushes three-dimensionally inside holes. Kids who score highly are trained for the Toilet-Cleaning Olympiad, meant to keep the citizenry battle-ready and internationally competitive. Eventually, the world crowns a toilet-cleaning champion—not surprisingly, someone with an off-the-charts T.I.Q. This person is the very best at a skill that is crucial for the survival of humanity. Are they a genius?

The question is hard to answer because our definition of genius is so inconsistent. Generally, we want geniuses to be good with their minds rather than with their hands, but we can make an exception for a surgeon or a chef. We expect them to discover new realms of knowledge; alternatively, they can be very good at an automatable skill like chess. Their talent should be incomprehensible to the masses, unless they’re a politician. We have recognized genius in the physical mastery of a bathroom staple like marble (Bernini) and even in an innovation involving a toilet (Duchamp). So why not in this champion cleaner? Is the difference simply that only one of these fields is associated with working-class, racialized women?

In “The Genius Myth: A Curious History of a Dangerous Idea” (Thesis), Helen Lewis, a staff writer at The Atlantic, argues that what we call genius depends on the norms of a given period, “on what our society values, and what it is prepared to tolerate.” Lewis does not take a hard stance against the very existence of genius; she grants that Shakespeare might have been one. Her issue is more with the license given to genius, and the resulting admiration of traits that are not all that admirable. The nineteenth-century Romantics, for example, liked their geniuses boyish, naughty, in the late stages of tuberculosis, and, best of all, dead by suicide. They believed that genius was a natural, childlike quality, and that too much education could corrupt an otherwise promising case.

A competing theory of genius was advanced by an early statistician named Francis Galton, a cousin of Charles Darwin. Galton studied a set of English judges and tallied their “eminent” relations, doing the same with members of the clergy and professors of classics at Cambridge University. He concluded that genius ran in families, that it was more likely to be found in Europeans than in the “lower races,” and, as Lewis puts it, “that although genius was carried in the female line, it did not show up in women.” (Galton published these conclusions in 1869, the same year that a small group of British women were, for the first time, allowed to take a university entrance exam.) Despite the obvious silliness of his methodology, which, among other issues, does not separate the advantages of nepotism from those of talent, Galton’s theories remain influential; students taking the modern MCAT, more than half of whom are women, are expected to be familiar with his work.

Galton wanted to rebrand genius as the picture of respectability and health. He took special issue with the Romantic conception of inspiration, which harked “perilously near to the voices heard by the insane”—a particular problem for him because insanity appeared also in the “lower races.” Today, we’ve reached a compromise on the idealization of madness: all kinds of people can hear voices, but it’s a sign of genius only among those who are unlikely to be shot by the police during a psychotic episode. The novelist Ottessa Moshfegh claims to take dictation from her narrators: “I just write down what the voice has to say.” John Nash, a Nobel Prize-winning creator of game theory who was forcibly hospitalized for schizophrenia, once told a colleague, “The ideas I had about supernatural beings came to me the same way that my mathematical ideas did. So I took them seriously.”