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...