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Space/Science » in reply to More agreement than disagreement

Argument has several levels
Tom Brosz — (archived)

There's a big difference between the various levels of this argument:

Extraterrestrial life: Probably extremely common, with most of it operating at the microscopic level, but many macroscopic versions as well. Even limiting it to carbon chemistry, there are probably billions of planets with such life, and possibly even one or two within the range of instruments on Earth that could detect the signs. Look for free oxygen, or some other element that is normally highly unstable in the environment.

Intelligent extraterrestrial life: Now we're getting iffy. Given the history of evolution on Earth, through all the ages of fish, amphibians, reptiles, and mammals, we are apparently the first truly intelligent life form. I can't think of any other evolutionary adaptation that is that unique (think animals shaped like fish for swimming. Includes, over all history, countless fish, reptiles, and mammals.) Although there is no way to prove this, I suspect that our intelligence is a freak evolutionary accident. Odds someone with smarts is close enough to Earth to listen to our radio signals, or send some out: very slim.

Intelligent extraterrestrial life capable of star travel: Now we are getting really rare. Unless one throws in the completely baseless (so far) idea that there is some form of "FTL" drive available, interstellar travel would be restricted to generational or relativistic flights. Odds someone has dropped by our particular planet: very VERY slim.

Now, of course, an error in these assumptions could change everything, and I probably should dress this up to the point where it can stand next to Drake's Equation, but there it is.

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