Happy birthday, Carl Sagan: Enjoy these 6 bits of wisdom from the science legend

Monday would have marked the 81st birthday of Cosmos host and science icon Carl Sagan. In recognition of the occasion, here are six of his most potent and poignant statements on not only the stars, but ourselves:

1. What we do with our world, right now, will propagate down through the centuries and powerfully affect the destiny of our descendants. It is well within our power to destroy our civilization, and perhaps our species as well. If we capitulate to superstition, or greed, or stupidity we can plunge our world into a darkness deeper than time between the collapse of classical civilization and the Italian Renaissance. But, we are also capable of using our compassion and our intelligence, our technology and our wealth, to make an abundant and meaningful life for every inhabitant of this planet. To enhance enormously our understanding of the Universe, and to carry us to the stars.

Sagan made this plea for humanity to embrace the pursuit of knowledge during Episode 8 of Cosmos, "Journeys in Space and Time," which originally aired on Nov. 11, 1980.

2. How much money is spent every year on the planet on illegal drugs? Does the existence of such enormous amounts of money inevitably lead to corruption in police and military enforcement agencies, legislators, intelligence agencies and the Executive branch? If the financial rewards from drug dealing are so enormous, will not the suppression of the drug industry in one nation cause it to proliferate in another nation?

This is not science-related, per se. But it was revealed last October that Sagan was an advocate for the legalization of marijuana, and complained in private about being forced by NASA to sign an oath saying he would not use the drug while working for them as a contractor.

3. Think of the sun's heat on your upturned face on a cloudless summer's day. From 150,000,000 km away, we recognize its power. What would we feel on its seething, self-luminous surface, or immersed in its heart of nuclear fire? And yet, the sun is an ordinary -- even mediocre -- star. Our ancestors worshiped the sun, and they were far from foolish. It makes good sense to revere the sun and the stars, because we are their children.

In the Cosmos episode, "The Lives of the Stars," Sagan lays out our place within the universe, and how much closer we are to the stars than we might imagine.

4. We seem to claim privilege -- not by our work, but by our birth. By the mere fact that say, we're humans and born on Earth. We might call it the anthroprocentric -- the human-centered -- conceit. This conceit is brought closer to culmination by the notion that we are created in God's image. 'The creator and ruler of the entire universe looks just like me.' My, what a coincidence. How convenient and satisfying.

This statement is taken from Sagan's 1994 book Pale Blue Dot: A Vision of the Human Future in Space, in which he takes aim at the belief that Earth is the center of our universe.

5. I didn't have any near-death experiences. I didn't have a religious conversion ... I don't very much think about what it would be like for me, because I don't think it's likely there's anything that you think about after you're dead -- a long, dreamless sleep. But one thing that it has done is to enhance my sense of appreciation for the beauty of life. And of the universe, and of the sheer joy of being alive.

Sagan offered this insight on his fight against myelodysplasia during what would be his final interview -- a May 1996 discussion with Charlie Rose. He also issued a warning that has proven to be eerily prescient:

6. We've arranged a society on science and technology in which nobody understands anything about science and technology, and this combustible mixture of ignorance and power sooner or later is going to blow up in our faces. I mean, who is running the science and technology in a democracy if the people don't know anything about it. Science is more than a body of knowledge -- it's a way of thinking, a way of skeptically interrogating the universe with a fine understanding of human fallibility. If we are not able to ask skeptical questions, to interrogate those who tell us that something is true -- to be skeptical of those in authority -- then we're up for grabs for the next charlatan, political or religious, who comes ambling along.