first aired 28 September 1980, PBS, USA
'See that star?”
"You mean that bright red one?” his daughter asks in return
"Yes, it might not be there anymore. It might be gone by now, exploded or something. Its light is still crossing space, just reaching our eyes now. But we don't see it as it is, we see it as it was.”
Many people experience a stirring sense of wonder when they first confront this simple truth. Why? why should it be so compelling. The immense distances to the stars and the galaxies means we see everything in the past. Some as they were before the earth came to be. Telescopes are time machines.
Long ago, when an early galaxy began to pour light out in to the surrounding darkness no witness could have known that billions of years later. Some remote clumps of rock and metal, ice and organic molecules would fall together to form a place that we call earth. And surely nobody could have imagined that life would arise, and thinking beings evolve who would one day capture a fraction of that light and would try to puzzle out what sent it on its way.
We can recognize here a shortcoming, in some circumstances serious, in our ability to understand the world. Characteristically, willie-nilly we seem compelled to project our own nature onto nature. Man in his arrogance thinks himself a great work worthy of the interposition of a deity. Darwin wrote in his notebook, more humble, and I think truer to consider himself created from animals.
We're johnny-come-latelys; we live in the cosmic boondocks; we emerged from microbes in muck; Apes are our cousins; our thoughts are not entirely our own, and on top of that we're making a mess of our planet and becoming a danger to ourselves.
The trapdoor beneath our feet swings open. We find ourselves in bottomless free fall. We are lost in a great darkness and there is nobody to send out a search party. Given so harsh a reality, of course we are inclined to shut our eyes and pretend that we are safe and snug at home, that the fall is only a bad dream. If it takes a little myth and ritual to get us through a night that seems endless, who among us cannot sympathize and understand?
We long to be here for a purpose. Even though, despite much self-deception, none is evident. The significance of our lives and our fragile planet is then determined by our own wisdom and courage. We are the custodians of life's meaning. We long for parents to care for us, to forgive us of our errors, to save us from our childish mistakes. But knowledge of preferable to ignorance. Better, by far, to embrace the harsh reality than a reassuring fable.
Modern science has been a voyage into the unknown, with a lesson in humility waiting at every stop. Our common sense intuitions can be mistaken. Our preferences don't count. We do not live in a privileged reference frame. If we crave some cosmic purpose, then let us find ourselves a worthy goal.
Related content: Richard Feynman, Cargo Cult speech, Caltech, "The first principle is that you must not fool yourself'.
During the Middle Ages there were all kinds of crazy ideas, such as that a piece of rhinoceros horn would increase potency. Then a method was discovered for separating the ideas--which was to try one to see if it worked, and if it didn't work, to eliminate it. This method became organized, of course, into science.