At one end of the spectrum of what constitutes a fact is Richard Feynman's definition, which was anything he'd replicated himself in a lab. He considered everyt

At one end of the spectrum of what constitutes a fact is Richard Feynman's definition, which was anything he'd replicated himself in a lab. He considered everything else he knew to be based on faith (in people, in organizations, in whatever made the claim, but which he held in high enough esteem to actually believe.)