Extraordinary claims require extraordinary evidence. That truism, now known as the "Sagan standard" after science communication Carl Sagan, has been around in some form since David Hume first published it in the 1740s. But, with modern-day data collection, sometimes even extraordinary evidence isn't enough - it's how you interpret it. That's the argument behind a new pre-print paper by Luis Welbanks and their colleagues at Arizona State University and various other American institutions. They analyzed the data behind the recent claims of biosignature detection in the atmosphere of K2-18b and found that other non-biological interpretations could also explain the data.