I’m not very good at playing odds, though I do seem to pick up money routinely from a friend who is a Chicago Cubs fan (this year may be different — we’ll see). But bringing odds into the discussion of the Fermi Paradox can be an interesting exercise, and Princeton astrophysicist Richard Gott has already given the matter some thought. Let’s assume, for example, that you and I are not particularly special. We’re simply representative of the living beings who populate the universe.
If that’s the case, the odds say we’re probably living in one of the older civilizations, and one of the larger ones. That’s because more people would have lived in these cultures than in short-lived, smaller civilizations. It’s the Copernican principle at work, the notion that there is nothing special about the particular moment at which we’re observing what’s around us. Gott would say this has implications for other worlds.
“The sobering facts,” Dr. Gott says, “are that in a 13.7 billion-year-old universe, we’ve only been around 200,000 years, and we’re only on one tiny planet. The Copernican answer to Enrico Fermi’s famous question — Where are the extraterrestrials? — is that a significant fraction must be sitting on their home planets.”
Must be sitting there, that is, because that is precisely what we find ourselves doing. As to the argument that scientific progress is unstoppable, Dr. Gott notes in this New York Times article (from which the above quote is drawn) that civilizations like China’s abandoned exploration after making major inroads in world discovery. Just how representative was the Chinese experience? Indeed, the possibility exists that the window for a civilization to get into space and stay there is vanishingly small. We may not be at the beginning of the space program but near the middle of it. The odds on that are 50 percent.
We’re now entering a philosophical debate that is rather robust, and needless to say, Dr. Gott has his critics as well as his supporters. Here’s a link to an article by Bradley Monton and Brian Kierland that appeared in the Philosophical Quarterly (PDF warning). And have a look at John Tierney’s follow-up to his Times article. Here he quotes Monton (University of Kentucky) on Gott’s ideas on space colonization:
…I think Gott is right — it should be a major priority that we work on establishing self-sufficient colonies on other planets. Technology hasn’t been around very long, and in the absence of evidence this should lead us to think that it’s likely that it won’t be around very long in the future. But we shouldn’t be fatalistic about Copernican Principle predictions — there are things we can do to make it more likely that technology-adept intelligent life will continue to be around in the future. Besides the obvious things we can do (e.g. controlling loose nukes, preventing pandemics), establishing self-sufficient colonies will clearly make a difference.
Now ponder Gott’s analysis against the familiar science fiction idea that we are a young civilization moving into a galaxy filled with far advanced races. As Tierney notes, pick any American at random and you’ve probably picked one from a town that’s larger than median size, because that’s where the population is. Similarly, we’re probably in a relatively representative civilization right now. I like Tierney’s finish:
In fact, we could assume that the typical civilization reaches our stage of development, applies the Copernican principle, realizes that it’s 95-percent certain to go extinct unless it takes an extraordinary step like colonizing other planets — and then goes extinct even though it’s aware of its eventual doom.
Is that going to happen to us, too? What can we do to beat those odds?
Beating the odds is something we seem suited to doing. But it requires resolve and a commitment to living for more than the present. The stakes are huge, for if we cluster all our resources on a single world, we run the risk of losing everything. “Sooner or later something will get us if we stay on one planet,” says Gott. “By the time we’re in trouble and wish we had that colony on Mars, it may be too late.” That means we’d better get to Mars sooner rather than later before the window closes.
The Monton and Kierland article is “How to Predict Future Duration from Present Age,” The Philosophical Quarterly Volume 56, Number 222 (January 2006), pp. 16-38. Those familiar with Richard Gott (and I count myself a great admirer), will know about his Time Travel in Einstein’s Universe: The Physical Possibilities of Travel Through Time (New York: Houghton Mifflin, 2001), a book I can’t recommend too highly. A quote apropos to our work here: “…one of the things we should understand about time is that we have just a little.” Using it wisely should be our greatest concern.