At the heart of science is an essential tension between two seemingly
contradictory attitudes -- an openness to new ideas, no matter how
bizarre or counterintuitive they may be, and the most ruthless skeptical
scrutiny of all ideas, old and new. This is how deep truths are
winnowed from deep nonsense. Of course, scientists make mistakes in
trying to understand the world, but there is a built-in error-correcting
mechanism: The collective enterprise of creative thinking and skeptical
thinking together keeps the field on track.
-- Carl Sagan, "The Fine Art of Baloney Detection," Parade, February 1, 1987