Driving home tonight, I listened to a BBC program about the search for extra-terrestrial intelligence (SETI). I never heard the name of the American scientist who was answering questions from a British audience, but his style and sense of humor were engaging.
He led me to think, "This is why I prefer science over religion; open-mindedness is so appealing."
Someone asked if he thought that aliens were visiting Earth. His reply: this is within the realm of possibility, because it wouldn't violate the laws of physics. If they were traveling at the speed of light, it could take aliens thousands of years to reach our planet. But if they had patience, the trip could be made.
He went on to say, though, that the evidence is lacking. Just because something is possible doesn't mean it is true, or real.
The SETI scientist acknowledged that an amazingly large number of people believe that they are being transported to alien spaceships during the night, where experiments are conducted on them.
But he wondered why, if this really was happening, more spouses weren't waking up and calling authorities to report that their wife or husband had suddenly disappeared. He also noted that while claimed UFO sightings have been common for quite a few decades, they haven't made any difference to human life.
No new knowledge. No credible evidence. No effect on society.
By contrast, he said, no sixteenth century Aztec would have said "I wonder if those really were Spaniards I saw." At least, not for long. The effects of visitations by Spaniards quickly became evident.
Of course, it's possible that space aliens are nearby yet hiding themselves from view, just as it's possible that God is doing the same. There's that possible again.
Open-mindedness embraces the prospect of possibilities, while demanding demonstrable evidence before considering that a possible deserves a promotion to probable.
It's nice to see that the Pope's chief astronomer says that aliens could exist. I wonder, though, if he's equally open to the possibility that God doesn't exist.
Personally, I'd be less surprised to learn that solid evidence has been found for advanced extra-terrestrial life than that solid evidence has been found for God. With hundreds of billions of stars in each of hundreds of billions of galaxies in the universe, it sure seems likely that Earth isn't alone in harboring living beings.
However, the scientist I heard on BBC offered up some convincing reasons why it's likely that if we ever do receive communications from an extra-terrestrial source, that alien intelligence will be mechanical, not natural.
His argument was that given how much more rapidly computers are progressing in intelligence than humans are, this probably holds true for an alien civilization as well.
So while biological life is necessary to create machine intelligence, it doesn't take long (on a cosmic time scale) before computers -- or devices we can't even conceive of -- become the dominant "life form" on a planet.
Of course, there's cinematic evidence that this has already occurred.