American astrophysicist, cosmologist and author (1934–1996)
Carl Edward Sagan (November 9, 1934 – December 20, 1996) was an American astronomer and popular science author.
- "It seems to me what is called for is an exquisite balance between two conflicting needs: the most skeptical scrutiny of all hypotheses that are served up to us and at the same time a great openness to new ideas... If you are only skeptical, then no new ideas make it through to you … On the other hand, if you are open to the point of gullibility and have not an ounce of skeptical sense in you, then you cannot distinguish the useful ideas from the worthless ones."
- Simple: I think what we need is a delicate balance between two needs that go against each other: the most careful doubt of every hypothesis that is given to us, and at the same time a great openness to new theories... If all you do is doubt, then no new ideas make it through to you … On the other hand, if you believe everything you read and don't have any doubtful sense, then you cannot tell the difference between the useful ideas and the useless ones.
- "The truth may be puzzling. It may take some work to grapple with. It may be counterintuitive. It may contradict deeply held prejudices. It may not be consonant with what we desperately want to be true. But our preferences do not determine what's true. We have a method, and that method helps us to reach not absolute truth, only asymptotic approaches to the truth — never there, just closer and closer, always finding vast new oceans of undiscovered possibilities. Cleverly designed experiments are the key."
- Simple: The truth may be hard to understand. It may be something we have to struggle with. It may be strange and not what we expect. It may go against what we believe deep inside. It may not be what we want to be true. But what we want does not decide what's true. We have a way (science), and that way does not tell us perfect truth, but what it tells us is always closer to the truth than last time — never there, just closer and closer, always finding new things that are possible. Making experiments wisely is the key.
- "Advances in medicine and agriculture have saved vastly more lives than have been lost in all the wars in history."
- Simple: The number of people who are alive because of better medicine and better farms is bigger than the number of people who are dead because of all the wars in history.
- "We've tended in our cosmologies to make things familiar. Despite all our best efforts, we've not been very inventive. In the West, Heaven is placid and fluffy, and Hell is like the inside of a volcano. In many stories, both realms are governed by dominance hierarchies headed by gods or devils. Monotheists talked about the king of kings. In every culture we imagined something like our own political system running the Universe. Few found the similarity suspicious."
- Simple: Most of the time, when we (humans) make theories of how the universe works, we use ideas that we already know a lot about. Even though we tried our best, we weren't good at inventing new ideas. People from the West think Heaven is peaceful and soft, and Hell is like the inside of a volcano (fire mountain). In many stories, both places have governments that have gods or devils for kings. People who believe in God called God the king of kings. Every society imagined that something like its own government runs the whole universe. No one thought it was funny that the two governments were the same.
- "Evolution is a fact, it's not a theory. It really happened."