Science, Discovery and the Future

1The photograph was taken from a distance of approximately six billion kilometres. The Voyager 1 spacecraft, having spent thirteen years travelling outward through the solar system, turned its camera back toward the sun in 1990 at the request of the astronomer Carl Sagan. The resulting image shows Earth as a fraction of a pixel: a pale blue dot suspended in a shaft of scattered sunlight. Sagan wrote about it afterward in terms that have never quite been improved upon. Every human being who ever lived, every king and peasant, every young couple in love, every saint and sinner, lived on that mote of dust suspended in a sunbeam.

2Science does several things simultaneously, and not all of them are comfortable. It expands the boundaries of what we know, which is what it is celebrated for. But it also, persistently, shrinks our sense of our own importance. The Earth is not the centre of the solar system. The solar system is not the centre of the galaxy. The galaxy is one of approximately two trillion in the observable universe. Each of these discoveries diminished the idea that human beings occupy a special place in the cosmos, and each of them was resisted, sometimes violently, before being reluctantly accepted.

3The history of science is also a history of being wrong in instructive ways. Phlogiston was once the accepted explanation for combustion. Luminiferous ether was the medium through which light was assumed to travel. Stomach ulcers were believed, for most of the twentieth century, to be caused by stress and diet, until two Australian researchers discovered that the real cause was a bacterium, and were awarded the Nobel Prize for an idea that had been dismissed as absurd for nearly a decade. The lesson science teaches about itself is that current knowledge is the best available approximation, not the final word.

4None of this makes science less valuable. It makes it more honest than most other ways of knowing. The willingness to be wrong, to publish findings that contradict previous findings, to update the model when the data demands it: these are not weaknesses. They are the mechanisms by which knowledge becomes more reliable over time. A belief system that cannot be falsified is not producing knowledge. It is producing certainty, which is a different and more dangerous thing.

5The pale blue dot is still out there, still moving. Voyager 1 is now in interstellar space, the first human-made object to leave the solar system entirely. It carries a golden record containing sounds and images of Earth: music, greetings in fifty-five languages, the sound of rain and wind and surf. It is a message to whoever might, across an unimaginable distance, one day find it. Whether anyone ever does is not the point. The point is that we sent it.