Passages from the last episode of Neil deGrasse Tyson’s “Cosmos”.
Early in the episode, he describes a thought experiment:
Pick a star, any one of the hundreds of billions of stars in our Milky Way galaxy, which is just one galaxy out of a hundred billion in the known universe.
How about that star, or that one? Okay, this one. It’s orbited by dozens of planets and moons. Suppose on one of them, there lives an intelligent species, one of the ten million life forms on that planet, and there’s a subgroup of that species who believe they have it all figured out: their world is the center of the universe, a universe made for them, and that they know everything that they need to know about it—their knowledge is complete.
How seriously would you take their claim?
[pull steadily back to reveal millions of other stars…]
Toward the end of the show, there is a long (famous and moving) quotation/narration by Carl Sagan, about how everyone we’ve ever known or known of has existed on the tiny pale blue dot of Earth as seen looking back from the outer solar system by the Voyager spacecraft. Here it is on YouTube. (The episode plays this over animation of the Voyager moving outward through the solar system, passing Mars, Jupiter, Saturn…)
At the end of the episode, Tyson looks back to summarize the principles that have allowed humankind to perceive and understand the vast cosmos we live in, and then draws it all to a close. The understanding we have so far has been the work of generation of searchers, who took “five simple rules to heart”:
(1) Question authority. No idea is true just because someone says so, including me.
(2) Think for yourself. Question yourself. Don’t believe anything just because you want it. Believing something doesn’t make it so.
(3) Test ideas by the observations gained from evidence and experiment. If a favorite idea fails a well-designed test, it’s wrong! Get over it.
(4) Follow the evidence wherever it leads. If you have no evidence, reserve judgment.
(5) And perhaps the most important rule of all: Remember, you could be wrong. Even the best scientists have been wrong about some things. Newton, Einstein, and every other great scientist in history—they all made mistakes. Of course they did—they were human.
Science is a way to keep from fooling ourselves, and each other.
Have scientists known sin? [image of atom bomb] Of course—We have misused science, just as we have every other tool at our disposal, and that’s why we can’t afford to leave it in the hands of a powerful few. The more science belongs to all of us, the less likely it is to be misused.
These values undermine the appeals of fanaticism and ignorance, and, after all, the universe is mostly dark, dotted by islands of light.
Learning the age of the earth or the distance to the stars, or how life evolves—what difference does that make?
Part of it depends on how big a universe you’re willing to live in. Some of us like it small. That’s fine. Understandable.
But I like it big. And when I take all of this into my heart and my mind, I’m uplifted by it. And when I have that feeling, I want to know that it’s real, that it’s not just something happening inside my own head, because it matters what’s true, and our imagination is nothing compared with Nature’s awesome reality.
I want to know what’s in those dark places. And what happened before the big bang. I want to know what lies beyond the cosmic horizon, and how life began. Are there other places in the cosmos where matter and energy have become alive … and aware?
I want to know my ancestors—all of them. I want to be a good, strong link in the chain of generations. I want to protect my children, and the children of ages to come.
[scenes shifts to the California coast, where the series began]
We, who embody the local eyes and ears and thoughts and feelings of the cosmos, we’ve begun to learn the story of our origins, star stuff contemplating the evolution of matter, tracing that long path by which it arrived at consciousness.
We and the other living things on this planet carry a legacy of cosmic evolution spanning billions of years.
If we take that knowledge to heart, if we come to know and love nature as it really is, then we will surely be remembered by our descendants as good, strong links in the chain of life.
And our children will continue this sacred searching, seeing for us as we have seen for those who came before, discovering wonders as yet undreamt of in the cosmos.