1,131 Quotes by Carl Sagan

Intuitive: The word conveys, I think, a diffuse annoyance at our inability to understand how we come by such knowledge.

Major scientific insights are characteristically intuitive, and equally characteristically described in scientific papers by linear analytical arguments. There is no anomaly in this: it is, rather, just as it should be. The creative act has major right-hemisphere components. But arguments on thevalidity of the result are largely left-hemisphere functions.

One of the great commandments of science is, "Mistrust arguments from authority." (Scientists, being primates, and thus given to dominance hierarchies, of course do not always follow this commandment.) Too many such arguments have proved too painfully wrong. Authorities must prove their contentions like everybody else. This independence of science, its occasional unwillingness to accept conventional wisdom, makes it dangerous to doctrines less self critical, or with pretensions of certitude.

Every major power has some widely publicized justification for its procurement and stockpiling of weapons of mass destruction, often including a reptilian reminder of the presumed character and cultural defects of potential enemies (as opposed to us stout fellows), or of the intentions of others, but never ourselves, to conquer the world.

A galaxy is composed of gas and dust and stars - billions upon billions of stars. Every star may be a sun to someone.

La ausencia de pruebas no es prueba de ausencia.

Each star system is an island in space, quarantined from its neighbors by the light-years. I can imagine creatures evolving into glimmerings of knowledge on innumerable worlds, every one of them assuming at first their puny planet and paltry few suns to be all that is. We grow up in isolation. Only slowly do we teach ourselves the Cosmos.

Observation: there was absolutely nothing to see on Venus. Conclusion: it must be covered with life.

The first law of bureaucracy is to guarantee its own continuance.