What do you do when you are faced with several different gods each claiming the same territory? The Babylonian Marduk and the Greek Zeus was each con… - Carl Sagan

A central lesson of science is that to understand complex issues (or even simple ones), we must try to free our minds of dogma and to guarantee the freedom to publish, to contradict, and to experiment. Arguments from authority are unacceptable. We are all fallible, even leaders. But however clear it is that criticism is necessary for progress, governments tend to resist.

— Dedicarle tiempo a la física es un lujo — le comentó a Ellie — . Mucha gente podría hacer lo mismo si contara con iguales oportunidades, pero si tenemos que recorrer las calles en busca de comida, no nos quedará tiempo para la física. Mi obligación, por lo tanto, es mejorar las condiciones para los jóvenes científicos de mi país.

Humans may crave absolute certainty; they may aspire to it; they may pretend, as partisans of certain religions do, to have attained it. But the history of science — by far the most successful claim to knowledge accessible to humans — teaches that the most we can hope for is successive improvement in our understanding, learning from our mistakes, an asymptotic approach to the Universe, but with the proviso that absolute certainty will always elude us.