According to Friedel, the historian, scientists rely on the stubborn conviction that an obvious obstacle can be overcome. “There is a degree of suspension of disbelief that a lot of good research has to engage in,” he said. “Part of the art—and it is art—comes from knowing just when it makes sense to entertain that suspension of disbelief, at least momentarily, and when it’s just sheer fantasy.” Lord Kelvin, famous for installing telegraph cables on the Atlantic seabed, was clearly capable of overlooking obstacles. But not always. “Before his death, in 1907, Lord Kelvin carefully, carefully calculated that a heavier-than-air flying machine would never be possible,” Friedel says. “So we always have to have some humility. A couple of bicycle mechanics could come along and prove us wrong.”

John Colapinto, ‘Material Question’, The New Yorker, 22 December, 2014