The suppression of uncomfortable ideas may be common in religion or in politics, but it is not the path to knowledge, and there's no place for it in the endeavor of science. We do not know beforehand where fundamental insights will arise from about our mysterious and lovely solar system. The history of our study of our solar system shows us clearly that accepted and conventional ideas are often wrong, and that fundamental insights can arise from the most unexpected sources.
Carl SaganOur intelligence is imperfect, surely, and newly arisen; the ease with which it can be sweet-talked, overwhelmed, or subverted by other hardwired propensities - sometimes themselves disguised as the cool light of reason - is worrisome.
Carl SaganCenturies hence, when current social and political problems may seem as remote as the problems of the Thirty Years' War are to us, our age may be remembered chiefly for one fact: It was the time when the inhabitants of the earth first made contact with the vast cosmos in which their small planet is embedded.
Carl SaganIt would be wryly interesting if in human history the cultivation of marijuana led generally to the invention of agriculture, and thereby to civilization.
Carl SaganPerhaps, in retrospect, there would be little motivation even for malevolent extraterrestrials to attack the Earth; perhaps, after a preliminary survey, they might decide it is more expedient just to be patient for a little while and wait for us to self-destruct.
Carl SaganIn many cultures it is customary to answer that God created the universe out of nothing. But this is mere temporizing. If we wish courageously to pursue the question, we must, of course ask next where God comes from? And if we decide this to be unanswerable, why not save a step and conclude that the universe has always existed?
Carl Sagan