Nós criamos uma civilização global em que os elementos mais cruciais — o transporte, as comunicações e todas as outras indústrias, a agricultura, a m… - Carl Sagan

"I'm frequently asked, "Do you believe there's extraterrestrial intelligence?" I give the standard arguments- there are a lot of places out there, the molecules of life are everywhere, I use the word billions, and so on. Then I say it would be astonishing to me if there weren't extraterrestrial intelligence, but of course there is as yet no compelling evidence for it.
Often, I'm asked next, "What do you really think?"
I say, "I just told you what I really think."
"Yes, but what's your gut feeling?"
But I try not to think with my gut. If I'm serious about understanding the world, thinking with anything besides my brain, as tempting as that might be, is likely to get me into trouble. Really, it's okay to reserve judgment until the evidence is in."

Thomas Jefferson and George Washington owned slaves; Albert Einstein and Mohandas Gandhi were imperfect husbands and fathers. The list goes on indefinitely. We are all flawed and creatures of our times. Is it fair to judge us by the unknown standards of the future? Some of the habits of our age will doubtless be considered barbaric by later generations – perhaps for insisting that small children and even infants sleep alone instead of with their parents; or exciting nationalist passions as a means of gaining popular approval and achieving high political office; or allowing bribery and corruption as a way of life; or keeping pets; or eating animals and jailing chimpanzees; or criminalizing the use of euphoriants by adults; or allowing our children to grow up ignorant.

In science we may start with experimental results, data, observations, measurements, ‘facts’. We invent, if we can, a rich array of possible explanations and systematically confront each explanation with the facts.