No number of sightings of white swans can prove the theory that all swans are white. The sighting of just one black one may disprove it.
Karl PopperI have come to the conclusion that Darwinism is not a testable scientific theory, but a metaphysical research programme.
Karl PopperYou cannot have a rational discussion with a man who prefers shooting you to being convinced by you.
Karl Popper[Great scientists] are men of bold ideas, but highly critical of their own ideas: they try to find whether their ideas are right by trying first to find whether they are not perhaps wrong. They work with bold conjectures and severe attempts at refuting their own conjectures.
Karl Popper