Wednesday, March 7, 2012

If Aliens, then God?

Recently, I was surprised to learn that many evangelical Christians believe either that there is no other intelligent life in the universe or that any such beings would be demons, not people. Apparently, going by the comments on that article, this is because Christ died for humanity, not them, so either God is condemning countless aliens to Hell or they don't exist. (Or something like that; I am thankfully not an evangelical theologian.)

Regardless, I found it surprising because I think the one thing that could possibly get me to question my atheism is the discovery of intelligent life that did not originate on Earth.

Let me explain.

I think it is now generally accepted among the scientifically (and even science-fictionally) literate that what I call a "Star Trek universe" is absurd--that is, a universe teeming with beings that share none of our evolutionary history, and yet look enough like us to be played by human actors with rubber appliques.

The reasoning is simple. Evolution is a highly contingent process; organisms evolve in response to their environment, but one of the largest defining factors of that environment is the presence of other organisms! If most fruit did not change color when ripe, would primates have color vision, for example? Probably not, unless some other feature of our environment made it advantageous.

As Stephen J. Gould was fond of putting it, if you rewound the history of life on Earth and started from the beginning, miniscule early differences would grow rapidly to make the resulting organisms entirely unrecognizable. Take a look at the Burgess Shale fossils to see just how alien life on Earth can be, and those are organisms that shared the first 3 billion or so years of their evolution with us!

So, we have a long list of human features which were evolutionarily advantageous at one point in our ancestry, and remained non-harmful or could be adapted into something advantageous, but there is no reason to expect them to have been advantageous in the environment where a Klingon or Minbari evolved, features like:

  • DNA
  • Oxygen metabolism
  • Organelles
  • Multicellularity
  • Triptoblasty
  • Bilateral symmetry
  • Two biological sexes (as opposed to three or one or seventeen)
  • Keeping most of our sensory apparatus at one end of our body
  • Endoskeleton
  • Two pairs of limbs adapted to different purposes
  • Upright posture
  • Hair
  • Skin
  • Five-fingered hands (as opposed to twelve or three or tentacles, for that matter)
The list is unbelievably long--it would be, in fact, a complete description of a human being. The Drake equation doesn't help, here; the solution space for evolution is infinitely large, while the universe is merely very very large, and thus no matter how many Earthlike planets teeming with life there are, the probability of two of them independently evolving humanoids is still a finite number divided by infinity.

For some reason, however, while this seems to be generally accepted for physical features, people balk at accepting it is also true for our status as sophonts. Sophontry is not a single feature; it is a large number of different features, each of which occurs independently in some form in other species, that together comprise what we call a sophont. Remove even one, and the result, while interesting, is not recognizably a sophont--not a "new civilization." These features include:

  • Nth-order agency attribution: Agency attribution is the capacity to distinguish between agents (entities that act with intent) and non-agents, and respond accordingly. It is the ability to respond differently to grass rustling because a tiger is passing and grass rustling because of the wind. Most vertebrates and a handful of invertebrates possess it. Second-order agency attribution is the ability to recognize that other entities have agency attribution and respond accordingly--the ability to disguise one's intent, in other words. This is reasonably widespread among the mammals and some birds. Third-order agency attribution is the ability to recognize the possibility of deception, essentially, and has been observed in some great apes. A typical game of cops and robbers involves something like 9th-order agency attribution, and there is no known upper limit to humans knowing that you know that they know that you know that...
  • Self-awareness.
  • Ability to contemplate counterfactuals and possible futures.
  • Modeling: The ability to learn through observation, rather than conditioning.
  • Culture: Passing information both vertically to offspring, and horizontally to other individuals.
  • Language or similar.
  • Complex tool-use, including the ability to improvise tools previously not observed.
  • Problem-solving ability.
  • Pattern-recognition ability.
  • Intellectual empathy.
  • Emotional empathy.
And, of course, many others. Some of these may depend on one another in order to exist, but others can exist independently. It is possible to imagine a complex tool-using culture that has no self-awareness, empathy, or language-equivalent, for example. We thus run into the same problem as humanoids. No matter how we fiddle the Drake equation, the f(i) term is cheating; we are really asking what the probability is of a random walk in an infinite space happening to hit a predefined point (hint: it's infinitesimal). So again, we are looking at an event so unlikely as to be effectively impossible.

Now, some developments appear to actually be selected for in a wide variety of environments; they are so broadly useful that they recur again and again. Birds and bats, for example, have both hit on variants of wings, despite their common ancestor having none. Eyes operating on similar principles to our own evolved independently in mollusks (although we do likely have a common ancestor with light-sensitive spots to start the process off).

However, there is no reason to believe this is the case for most of the elements of intelligence. And there is even less reason to believe it is the case for intelligent life to develop off Earth; after all, everything with wings that we know of evolved on the same planet; maybe there is something unique about Earth that encourages wings, or some coincidental occurrence way back in the history of life on Earth that shaped the environment in such a way as to encourage wings. Equally, there may be some chance event in the history of Earth that set the stage for agency attribution to evolve multiple times (one possible candidate for that event would be the development of heterotrophs).

So really, what it would mean if we found intelligent aliens is that something about the universe is encouraging all these traits to develop in concert in many different environments. It would mean that the universe is somehow friendly to intelligence in a way that was not previously obvious. That wouldn't be enough to make me believe there was something divine at work, but it is unlikely enough to make me pause and reconsider. Even more so if said aliens follow something resembling a specific Earth religion.

Still, the way to bet is that we are the only intelligent life the universe has ever known. Sad and humbling, but perhaps that gives yet more reason to treat one another better. And at least we will always have science fiction for our alien-civilization fix...


  1. Since all the examples of wings/intelligence we know about evolved on Earth, you conclude there's probably something special about Earth that means wings/intelligence are unlikely to evolve on any other planet in the whole vast universe?

    I can see a problem with your argument here. We don't know about any other planets with life at all. If we knew of 99 roughly Earth-like worlds where nothing had wings, you might have a point. You yourself have said that wings evolved independently on Earth in birds and bats (and pterodactyls, I think several times in arthropods, plus various gliders). Given what we know, on a roughly Earth-like world with life (which may well be a very very low percentage of all planets, but still numerous given the size of the universe) it would be strange if wings of some sort didn't evolve.

    Your definition of intelligence is weirdly restrictive. You have a list of supposedly vital attributes of a "sophont" (which as far as I can tell seems to be a term made up by Poul Anderson). But why does lacking one of those attributes make a species not count as a civilisation?

    Is a sociopath or an autist who lacks "emotional empathy" somehow not a "sophont"? If we found a tool-using, space-faring civilisation that lacked one of the points on your checklist (like the aliens in Blindsight who are intelligent but not conscious), would they somehow not count as "intelligent"?

  2. I don't follow this train of thought at all.

    Are you saying that you can conceive of no evolutionary advantage to problem solving, pattern recognition, or language, so the only answer to another species developing these is a sign of higher-power meddling?

    You're comparing specific physical features to a broad, vague characteristic (or subset of characteristics).

    It would be more appropriate to wonder whether species on other planets would be developing methods for protection (skin/exoskeleton), communication (language/sound/color/etc.), a genetic basis for information (DNA/RNA), a way to recognize and avoid danger (problem solving/pattern recognition/risks).

    The *specifics* of these strategies are likely to vary - I would be gobsmacked if we ran across aliens speaking English - but the strategies are likely to be similar on planets that support life, even if the details vary.

  3. Wings have evolved many times, in different - but recognisably similar - forms, working on the same basic principles.
    They did so because the ability to fly/glide is a significant advantage. The advantage is out there in the phase space of 'possible evolutionary outcomes', and when a species moves in that direction it reaps the advantages.
    I do not see why intelligence is not exactly analogous to wings. I would fully expect alien intelligences to think very differently, and to have very different values from us. But every one of the tools which you break down 'intelligence' into is useful. Every one carries evolutionary advantage for a species where it develops. So while it might take many life-bearing worlds to bring forth one intelligent species that we could recognise as such, it would hardly seem an infinitesimal chance.
    Just as in a flightless world there are many available niches for any species that begins to fly, so in an intelligence-less world there are many niches available for any species that begins to develop mind.

  4. In fact, intelligent non-human animals with *many* of the points in your "sophont" checklist (although not all at once) have evolved multiple times on Earth. Apart from other primates, elephants, marine mammals, corvids and cephalopods have a lot of the points of the checklist. It certainly doesn't seem to be too much of a stretch to imagine a social land-squid or a tool-using elephant (like in Footfall).

    You suggest that heterotrophy might be a prerequisite for agency attribution that has evolved on Earth but not on other planets. Why do you think heterotrophy is unlikely to evolve or somehow unique to Earth? We don't have any data either way. Perhaps there is some "unlikely" transitional stage to the necessary complexity (perhaps evolving a nervous system, which I think has only happened once on Earth, in an early metazoan) - but say only 1 in 10,000 biospheres evolves nerves, given the scale of the universe, you would still expect other 'sophonts' to show up now and again.

    Given the recent observations of exoplanets which suggest that our solar system might be atypical (which might be a sampling error, I'm not an expert), it seems more likely that 'Earth-like' planets (with stable, hospitable conditions that can support the evolution of complex life rather than hardy bacteria) are very rare. And also, judging by the ongoing environmental catastrophe that the Anthropocene has brought to Earth, "sophonts" probably don't survive very long after they invent industry.

  5. Can't defend your ideas, eh?

  6. Seconding some of the previous commenters. Or thirding. I actually expect alien life to have some variant of DNA/RNA/etc--we've found amino acids in interstellar gas clouds! If amino acids form that easily in nature, I suspect organic chemistry dictates that the simplest organization for massive information storage (i.e., genetic code) will turn out to be strung-together amino acids.

    Mars almost certainly has life; too many hints of it found already. I wouldn't be surprised if the Jovian atmosphere supports life, either. It's warm enough, and there's enough fun organic chemicals brewing around in there to support many Earth extremophiles, let alone something that evolved for the environment. And that's just in our solar system, let alone all those other planets we are continuing to discover around other stars.

    Extremophiles are what convinced me that life is not only possible elsewhere, but probable. I'm firmly convinced that when we get out to where we can sample other planets first-hand and study them in detail, we'll trip over life everywhere we turn around. It's just hard to see from where we sit on Earth.

    Alien civilizations may be a bit rarer, though.

  7. Thanks for your comments, all! I have been meaning to address these comments for weeks, but other responsibilities keep interfering. At this point I think my best bet is just to write a second blog post further explaining my position and addressing the substantive points you've all made. Expect that at some point in the near future (in real-life terms, I don't operate on anything near Internet time).


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