Via HotAir, an interesting essay from Marcelo Gleiser:
However, there is a huge difference between simple life and complex life. Contrary to what many believe, evolution doesn’t lead to complex life forms: evolution leads to well-adapted life forms.
I agree. People tend to underestimate the power of the weak anthropic principle — no matter how unlikely the rise of complex life and intelligent life are, we have to observe them in our past in order for us to be here observing. Complex life may be very unlikely, and intelligent life may be almost infinitely unlikely — given an infinite universe, we would still expect to be here observing ourselves.
The Cambrian explosion in particular is not well-understood, and for the 3.5 billion years before it the Earth did not support complex life. Intelligent life has been around a much shorter proportion of the time, and industrial civilization is an eyeblink.
It may be that the preconditions for intelligent life are so unlikely that the odds of it evolving twice within a visible universe are essentially zero — in fact, one can make a strong case this is the most likely scenario.
Humanity spent the last couple centuries learning that we are not that special — upright animals on an insignificantly tiny, off-center speck in the galaxy which itself is an insignificantly tiny piece of the universe. We may spend the next couple centuries learning we are very special indeed.
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2 responses to “How Unlikely Are We?”
Yes, that is interesting. Interesting is not to be sneezed at.
I don’t see how we can figure it out until we go other places, but we can at least look at what we know.
Life might be totally unlikely, or it might be everywhere.
I read a sci-fi series by Ian Douglas.
He calls the idea that if there were life out there, we should have met them the Fermi Paradox (I’ve seen it called other things).
He explains it that there’s one very paranoid species out there that kills any species that gets too into interstellar travel.
Considering that any species should be able to cruise all around our galaxy in a million years (an eyeblink in the life of the Universe or even our galaxy), and it’s highly unlikely that we’re the first species (if intelligence is likely) it seems that life is either unlikely or something keeps it from traveling.
Maybe all intelligent species blow themselves up when they figure out nukes or maybe there is a species out there that blows up all intelligent life when they get it.
Or maybe there’s United Solar Systems that’s keeping people from coming here until we either blow ourselves up or get off the planet.
Or maybe they just don’t think we taste good.
Not very reassuring that.