To me Carl Sagan was an unknown, as I grew up in a non-English speaking country, but I’ve grown quite fond of his writings and video productions when I discovered them online. And recently I found an essay of him on scepticism:
At the heart of science is an essential balance between two seemingly contradictory attitudes--an openness to new ideas, no matter how bizarre or counterintuitive, and the most ruthlessly skeptical scrutiny of all ideas, old and new. This is how deep truths are winnowed from deep nonsense. The collective enterprise of creative thinking and skeptical thinking, working together, keeps the field on track. Those two seemingly contradictory attitudes are, though, in some tension.
The video rendition of this essay made by C0nc0rdance is a joy to watch: