Consider:
Among the countless Earths that, we are told, sail the galaxies (an estimate released last week offers 8.8 billion “just-right planets”), one or two may indeed be researchable, even reachable. And what if we find no life there?
Ah. Recall that the Copernican Principle is not evidence. It is an assertion: Earth cannot be a rare planet because that would make us special, which is philosophically unacceptable today.
So invoking the Principle, many of these planets must be inhabited. As Fox News puts it,
As for what [the 8.8 billion estimate] says about the odds that there is life somewhere out there, it means “just in our Milky Way galaxy alone, that’s 8.8 billion throws of the biological dice,” said study co-author Geoff Marcy, a longtime planet hunter from the University of California at Berkeley.
Caution: Biology is an awkward science to play dice with. One may as well argue that there must be several species of reasoning animals like humans on Earth because there are just so many species. But there aren’t several, just one. More.
Here is a curious thing about the Copernican Principle: The Principle does not apply to Mars, a planet about which we now know a fair bit. And our hardware has been there a few times, even if we have not (so far).
It is entirely okay to think that Mars is unusual. That is, the solid string of disappointments over life on Mars is not expected to lead to the conclusion that it might be typical, and therefore life might be rare in the galaxy.
On the contrary, Earth’s mediocrity is underscored by the fact that Earth has its very own Principle, one which is not invoked when dealing with other planets.
For good reasons, doubtless.
See also:
What has materialism done for science?
Big Bang exterminator wanted, will train
Copernicus, you are not going to believe who is using your name. Or how.
“Behold, countless Earths sail the galaxies … that is, if you would only believe”
Don’t let Mars fool you. Those exoplanets teem with life!