In June 2022, scientists at Durham University each received an internal email from Peter Vickers, a professor at its philosophy department. Besides a brief personalized greeting, each message was identical. The content was succinct: “Colors don’t exist in the external world, they’re just a way that human beings represent the world in their minds. Do you agree or disagree?”

“It was a philosophical question but, according to textbook science, grass isn’t really green, it’s just the light reflected from it has a certain wavelength,” Vickers says. “I thought there’d be a consensus on it.”

Instead, Vickers’ question prompted fierce semantic debate. Some colleagues argued that grass has objective properties — color being one of them. Others contended that only light exists in a physical form: what a human perceives as green is merely certain molecules reflecting electromagnetic radiation of a wavelength between 520 and 570 nanometers.

The open-ended, theoretical question rendered the survey data nearly worthless. Rather than general agreement, all that emerged was lively scientific and philosophical discussion across academic inboxes. But the high response rate gave Vickers encouragement: his idea for an Institute for Ascertaining Scientific Consensus could really work. All he needed was to ask a more straightforward line of inquiry.