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"