Carl Sagan

In our earliest history, so far as we can tell, individuals held to an allegiance toward their immediate tribal group, which may have numbered no more than ten or twenty individuals, all of whom were related by consanguinity. As time went on, the need for cooperative behavior — in the hunting of large animals or large herds, in agriculture, and in the development of cities — forced human beings into larger and larger groups. The group that was identified with, the tribal unit, enlarged at each stage of evolution. Today, a particular instant in the 4.5-billion-year history of Earth and in the several-million-year history of mankind, most human beings owe their primary allegiance to the nation-state (although some of the most dangerous political problems still arise from tribal conflicts involving smaller population units). Many visionary leaders have imagined a time when the allegiance of an individual human being is not to his particular nation-state, religion, race, or economic group, but to mankind as a whole; when the benefit to a human being of another sex, race, religion, or political persuasion ten thousand miles away is as precious to us as to our neighbor or our brother. The trend is in this direction, but it is agonizingly slow. There is a serious question whether such a global self-identification of mankind can be achieved before we destroy ourselves with the technological forces our intelligence has unleashed.

In the vastness of the Cosmos there must be other civilizations far older and more advanced than ours.

Ubi dubium ibi libertas: Where there is doubt, there is freedom. LATIN PROVERB

Voyages to the outer solar system are controlled from a single place on the planet Earth, the Jet Propulsion Laboratory (JPL) of the National Aeronautics and Space Administration in Pasadena, California.

A multitude of aspects of the natural world that were considered miraculous only a few generations ago are now thoroughly understood in terms of physics and chemistry. At least some of the mysteries of today will be comprehensively solved by our descendants. The fact that we cannot now produce a detailed understanding of, say, altered states of consciousness in terms of brain chemistry no more implies the existence of a “spirit world” than a sunflower following the Sun in it’s course across the sky was evidence of a literal miracle before we knew about phototropism and plant hormones.

The technological perils that science serves up, its implicit challenge to received wisdom, and its perceived difficulty, are all reasons for some people to mistrust and avoid it.

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.'''

If I finish a book a week, I will read only a few thousand books in my lifetime, about a tenth of a percent of the contents of the greatest libraries of our time. The trick is to know which books to read.

Sagan is an astronomer with one eye on the stars, another on history, and a third — his mind’s — on the human condition.…

Si queremos que el mundo escape de las temibles consecuencias del crecimiento de la población global y de los diez mil o doce mil millones de personas en el planeta a finales del siglo XXI, debemos inventar medios seguros y más eficientes de cultivar alimentos, con el consiguiente abastecimiento de semillas, riego, fertilizantes, pesticidas, sistemas de transporte y refrigeración. También se necesitarán métodos contraconceptivos ampliamente disponibles y aceptables, pasos significativos hacia la igualdad política de las mujeres y mejoras en las condiciones de vida de los más pobres.

Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.

All my life, I've wondered about life beyond the earth. On those countless other planets that we think circle other suns, is there also life? Might the beings of other worlds resemble us, or would they be astonishingly different? What would they be made of? In the vast Milky Way galaxy, how common is what we call life? The nature of life on earth and the quest for life elsewhere are the two sides of the same question: the search for who we are.

Science is based on experiment, on a willingness to challenge old dogma, on an openness to see the universe as it really is. Accordingly, science sometimes requires courage - at the very least the courage to question the conventional wisdom.

"Essa é uma das razões pelas quais as religiões organizadas não me inspiram confiança. Que líderes dos principais credos reconhecem que suas crenças talvez sejam incompletas ou errôneas, e criam institutos para revelar possíveis deficiências doutrinárias? Além do teste da vida cotidiana, quem verifica sistematicamente as circunstâncias em que os ensinamentos religiosos tradicionais talvez ja não se apliquem? (É concebível que as doutrinas e a ética que podem ter funcionado muito bem nos tempos patriarcais, patrísticos ou medievais sejam totalmente inválidas no mundo bastante diferente que habitamos hoje.) Que sermões examinam imparcialmente a hipótese de Deus? Que prêmios os céticos religiosos ganham das religiões estabelecidas - ou, nesse aspecto, que recompensas os céticos sociais e econômicos recebem da sociedade em que vivem?
A ciência, observa Ann Druyan, está sempre nos sussurrando ao ouvido: "Lembre-se, você é novo nisso. Pode estar equivocado. Já errou antes". Apesar de todo o discurso da humildade, mostrem-me algo comparável na religião. Acredita-se que as Escrituras sejam de inspiração divina - uma expressão com muitos significados. Mas e se forem simplesmente criadas por seres humanos falíveis?"

We will know which stars to visit. Our descendants will then skim the light years, the children of Thales and Aristarchus, Leonardo and Einstein.