“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.”

This is a quote on Liberty? Seriously? Turn off the scanner for the word "truth" - you are being led to erroneous results.

Sagan too often drank the Kool-Aid on PC science. Probably, as this quote suggests, because he really didn't understand what the scientific method is supposed to do. Science is skepticism. It requires experimental evidence that is repeatable by independent researchers. It is not openness to new ideas, it is the skeptics trying to prove an hypothesis wrong, without mercy or emotion. Science is not having individuals invest themselves in an idea to the point that they become religious believers in that idea. Creative ideas without evidence makes for great fiction but not great science.

Ken, the openness to new ideas without empirical evidence isn't inherently against the method and meaning of science. It gives way to the funding of hypotheses which challenge theories which don't yet demonstrate any inconsistencies, but may nonetheless be inaccurate. Einstein's theory of gravity eclipsing Newton's is a prime example. It should be added, though, that Einstein's theory was mercilessly scrutinized by countless scientists, including Einstein himself, until proper empirical evidence was found to support it decades after its inception. Openness to new ideas is, in a very important sense, skepticism of the present body of knowledge. Few people have written on the importance and proper practice of skepticism as thoroughly or as beautifully as Carl Sagan did.