In 1903, Mark Twain comforted Helen Keller, who had been accused of plagiarizing her story “The Frost King,” telling her in a letter, “All ideas are secondhand, consciously and unconsciously drawn from a million outside sources.” He took a harder line on his own intellectual property, however, campaigning so vigorously for stringent copyright laws that the American Bar Association later recognized him for his efforts.

A CIA report declassified in 2000 revealed concerns about extrasensory perception during the space race in the 1960s: a Russian newspaper argued that cosmonauts “get together mentally with each other easier than with people on Earth,” while a Chicago Tribune columnist worried that the Soviets “may be the first to put a human thought in orbit or achieve mind-to-mind communication with men on the moon.”

The ancient physician Galen catalogued the anxious delusions of his melancholic patients, including those of a man who “believes he has been turned into a kind of snail” and “runs away from everyone he meets lest his shell get crushed,” and those of another who “is afraid that Atlas, who supports the world, will become tired and throw it away, and he and all of us will be crushed and pushed together.”

In 2016, after saxophonist Dan Fabbio was diagnosed with a brain tumor, neuroscientists in Rochester, New York, used functional MRI scans to create a brain map indicating areas crucial for music processing. Fabbio was awake during the surgery and, once the tumor was removed, played a Korean folk song to ensure his skill on saxophone remained; the song’s short notes allowed him to take shallow breaths so his brain would not protrude from his opened skull.