The touching faith I have in mind is faith in the existence of intelligent life forms “out there” in the infinite reaches of the universe. For want of a better name I call these faithful ones the science-minded; they believe that the rigors and methodologies of the scientific method yield the only true empirical propositions. Yet they hold tenaciously to a quite unscientific belief in intelligent alien life forms.

(There are non-empirical true propositions, of course, but they belong to the realm of mathematics.)

The tendency to hold this faith is pretty powerful and when you ask for evidence the answer you get (sometime more complex, sometimes less) boils down to something like, “Look at the millions of stars out there. Surely around some of these stars there are planets with intelligent life forms. Can you doubt it?

Well, yes I can in the absence of evidence. Oh, it’s fun to imagine that “out there” are races of people enough like us to someday do cameo roles on remakes of Star Trek, but that is science fiction, not science.

At the risk of being a spoil sport I’d point out that in none of the  (admittedly small) samples of extra-terrestrial material have we found any evidence even of primitive life forms. In the absence of evidence we are not entitled to make any claims about the extra-terrestrial.

Do I think we should keep looking? Sure— since the truths we find along the way may be more important than the “truth” we don’t find.

A recent Princeton University study suggests that the expectation of life on other planets is based less on science than on optimism:

Princeton University researchers have found that the expectation that life — from bacteria to sentient beings — has or will develop on other planets as on Earth might be based more on optimism than scientific evidence.

Princeton astrophysical sciences professor Edwin Turner and lead author David Spiegel, a former Princeton postdoctoral researcher, analyzed what is known about the likelihood of life on other planets in an effort to separate the facts from the mere expectation that life exists outside of Earth. The researchers used a Bayesian analysis — which weighs how much of a scientific conclusion stems from actual data and how much comes from the prior assumptions of the scientist — to determine the probability of extraterrestrial life once the influence of these presumptions is minimized.

In fact, the researchers conclude, the current knowledge about life on other planets suggests that it’s very possible that Earth is a cosmic aberration where life took shape unusually fast. If so, then the chances of the average terrestrial planet hosting life would be low.

Read the report here.

And prepare yourself to live alone in an infinite universe.