Carl Sagan

"La prueba de ausencia no es prueba de ausencia"

"We can judge our progress by the courage of our questions and the depth of our answers, our willingness to embrace what is true rather than what feels good."

"Extraordinary claims require extraordinary evidence."

"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."

"For small creatures such as we the vastness is bearable only through love."

"We are star stuff harvesting sunlight."

"The nuclear arms race is like two sworn enemies standing waist deep in gasoline, one with three matches, the other with five."

"You can get into a habit of thought in which you enjoy making fun of all those other people who don't see things as clearly as you do. We have to guard carefully against it."

"Somewhere, something incredible is waiting to be known."

"We are all star stuff."

"Extraordinary claims require extraordinary evidence."

"I consider it an extremely dangerous doctrine, because the more likely we are to assume that the solution comes from the outside, the less likely we are to solve our problems ourselves."

"If it can be destroyed by the truth, it deserves to be destroyed by the truth."

"We've arranged a civilization in which most crucial elements profoundly depend on science and technology. We have also arranged things so that almost no one understands science and technology. This is a prescription for disaster."

"Who is more humble? The scientist who looks at the universe with an open mind and accepts whatever the universe has to teach us, or somebody who says everything in this book must be considered the literal truth and never mind the fallibility of all the human beings involved?"

"[When a religious couple wrote to Sagan about fulfilled prophecies, he wrote back in May 1996:]If ‘fulfilled prophecy’ is your criterion, why do you not believe in materialistic science, which has an unparalleled record of fulfilled prophecy? Consider, for example, eclipses."

"The idea that God is an oversized white male with a flowing beard, who sits in the sky and tallies the fall of every sparrow is ludicrous. But if by 'God,' one means the set of physical laws that govern the universe, then clearly there is such a God. This God is emotionally unsatisfying... it does not make much sense to pray to the law of gravity."

"We've arranged a civilization in which most crucial elements profoundly depend on science and technology. We have also arranged things so that almost no one understands science and technology. This is a prescription for disaster."

"One glance at a book and you hear the voice of another person, perhaps someone dead for 1,000 years. To read is to voyage through time."

"Science is a way of thinking much more than it is a body of knowledge."