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The ‘Great Filter’: I Wish Stephen Jay Gould Were Still Alive

Posted by samgr on May 15, 2008

So there’s a really interesting article in the MIT Technology Review by Nick Bostrom which basically argues that finding evidence of extraterrestrial life in our own solar system would be the worst thing that could ever happen to humanity.

Loosely the argument is this: we now know the galaxy is full of planets, so the fact that we’ve seen no evidence of extraterrestrial INTELLIGENT life means that there is likely some kind of “great filter” that precludes the advancement of civilization to the point when it can colonize or otherwise broadcast its existence to the rest of the galaxy. If the great filter is in the past from a human standpoint—i.e. if it’s very hard for life to evolve complexity or intelligence, or even for life to arise in the first place— that’s good news for us. We’ve already passed through the filter because we’re lucky and awesome. If it’s in our future—i.e. if there’s some technological discovery that tends to wipe out civilizations (don’t switch on the LHC!!!)— then we’re in deep trouble. We’re unlikely to be the first civilization to make it through the great filter.

So, says Bostrom, if we find life on Mars or Europa, that’s bad news. The more advanced the life is, the worse news it is. If life evolved independently somewhere else, it’s statistically much less likely that the filter is in the past. So the expected lifespan of human civilization gets a lot shorter.

Now some thoughts from me. This all ties in with a lot of what Stephen Jay Gould writes about in Wonderful Life. He doesn’t use the “great filter” terminology, but he argues pretty forcefully that evolution of life on Earth is wildly improbable. He doesn’t seem to think that the ORIGIN of life is that wacky though; it’s more that the transition from unicellular to multicellular organisms is very hard to achieve, and that the evolution of intelligence is in fact very unlikely.

So from Gould’s point of view (I would think), if we were to find some slime on Mars or even some jellyfish on Europa, that’s not quite as much of a disaster as Bostrom thinks it would be. Bostrom leans toward the great filter being the initial origin of life, where what Gould writes suggests that the filter is more likely one of the transitions along the very unlikely path from slime to us.

Another thing that interested me in Bostrom’s article was this passage:

“Now, it is possible to concoct scenarios in which the universe is swarming with advanced civilizations every one of which chooses to keep itself well hidden from our view. Maybe there is a secret society of advanced civilizations that know about us but have decided not to contact us until we’re mature enough to be admitted into their club. Perhaps they’re observing us as if we were animals in a zoo. I don’t see how we can conclusively rule out this possibility.”

This has always been something I’ve wondered about. To me, this seems almost as likely a solution to the Fermi paradox as the great filter dealy, but it’s true that there’s no real way to prove or disprove it for now. Something’s going on, in any case.


One Response to “The ‘Great Filter’: I Wish Stephen Jay Gould Were Still Alive”

  1. Barbara said

    Glad to hear about this article, which I will look for. And it’s always good to hear thoughts related to Wonderful Life (a wonderful book) and Stephen Jay Gould. Thanks for writing a real essay again, even if it’s a mini one.

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