Complex Numbers

Rare Earth

Okay, whoever keeps asking the question, "How could this year get any worse?" -- I want you to stop that shit right now. Never ask that again.

I learned of Chadwick Boseman's death a bit over an hour ago, so I'm getting drunk and watching Black Panther. But that doesn't mean I can't do a quick blog entry at my usual time.

Today's ties in with the entry from a couple of days ago, and it's written by a guy I know.

https://www.syfy.com/syfywire/do-aliens-exist-probably-are-they-intelligent-prob...

Do aliens exist? Probably. Are they intelligent? Probably not.

Just to be clear, my own speculation on the subject, as seen in "No, It's Not 36." , was based on stuff I'd figured out before I saw Plait's article. As you'll see, we are in fairly close agreement on these things.

I've been asked if I think life exists elsewhere, and my answer is always that I do. This is based upon a single fact: Life got a toehold on Earth very rapidly after the planet formed, just a few hundred million years.

Only in cosmology is "a few hundred million years" considered "very rapidly."

Maybe life usually takes billions of years, and we were lucky. We only have our one example of life arising and so it doesn't really tell us anything about how easy it is. All it tells us is that the chances of it happening are not 0.

The chances could be one in billions, trillions, or even more. Or it could be close to 1 in 1. We simply don't know, and we won't until we find other examples of life and study them closely. If it seems unreasonable for the chance to be 1 in a trillion, just remember: your odds of winning the lottery may be 1 in a billion when you buy the ticket, but once you've won, prior odds are irrelevant. Maybe we won the lottery. We'll find out eventually if this year would stop fucking with us.

A new study using a sophisticated form of statistical analysis shows that life is actually quite likely to arise if conditions allow it. Hurray! However, it also shows intelligent life is far less likely. Boo.

Which is fine and all, but any statistical analysis, sophisticated or not, boils down to guesswork in this sort of thing. And yet, I'm inclined to believe it. Perhaps because of confirmation bias. But just because I'm inclined to believe it doesn't make it true.

But they found that when they ran their calculations, changing the prior assumptions strongly influenced their result, giving wildly different answers. That's frustrating.

That also supports my "don't put too much weight on this analysis" suggestion. Phil goes on to explain some of the math involved, but I've already had too much wine to know what to paste and what not to paste here, so you'll have to read the article.

What about intelligence? Assuming life arose quickly, the odds of intelligent life evolving are actually slim. Looking at whether the probability is very close to 0 (meaning extremely rare intelligent life) or 1 (very common), Kipping's work favors the low probability at odds of just 3:2. In other words, it's more likely intelligent life is extremely rare.

Phil uses approximately the same definition of "intelligence" as I do; to wit: the ability to use technology to go into space. Those are the species we'd be most likely to encounter, if they exist. In my own opinion, sure, we could find there's a highly advanced squid-like civilization under the ice of Jupiter's moon Europa, but our own squids are pretty damn clever and they're not building rockets. More, we can't seem to communicate with them.

But if you like to gamble, it implies that the best bet is that life is common, but intelligence is rare.

This study, this article, and my own thoughts on the subject are not new. There's a thing called the Rare Earth Hypothesis, which, in a nutshell, asserts that the particular combination of conditions the Earth has experienced and allowed creatures to evolve who could build rockets is probably rare in the universe.

He hasn't proven anything, because that's not how this kind of probability works. He's just shown that, given these assumptions, life is likely to be common and intelligence rare.

Leaving this here because it's important. As I noted before, I could be wrong and I kinda hope I am. Also, again, it's a really big universe, and lots of things are possible... somewhere.

Anyway, if you have the time and desire, read the article and watch the video embedded in it. There's also apparently a Tweetstorm at the link, but I've arranged my browser to pretend that the blight on the Universe known as Twitter doesn't exist, so I can't see it.

And now, back to getting drunk and watching Black Panther.