It’s hard to imagine a better example of this than polywater. “The data was right, but our interpretation was wrong,” my great-uncle told me. Technically, he’s correct: His team produced an accurate infrared spectrum reading of the tiny amounts of the sample they tested, and it didn’t match any other substance in their database. But if they had maintained a more skeptical approach, they might have considered other possibilities—such as sweat—before drawing up a novel chemical structure and giving their material a catchy new name. “The critical thing, whenever you find something that’s really strange, is to try to disprove it, rather than trying to prove it’s there,” Rousseau reminded me. In other words, in their excitement, my great-uncle’s team forgot the maxim popularized by Carl Sagan: Extraordinary claims require extraordinary evidence.