Subconsciously, the researchers who look for sentience beyond Earth in the effort known as Seti (the Search for Extraterrestrial Intelligence), make a similar [anthropomorphic] mental picture of their quarry. The idea of Seti is to use large antennas to possibly eavesdrop on radio transmissions from technically competent aliens. Its practitioners don’t really insist that the guys behind the microphone be either gray or glabrous, but they do – implicitly – assume that they’ve evolved on a world that, like Earth, is wrapped in oceans and an atmosphere. In other words, that the aliens are biological.

So Seti experiments often train their radio ears on star systems that seem most likely to host earth-like worlds.

That sounds both plausible and responsible. Sure, you could protest that alien life doesn’t have to be life as we know it, a pleasant observation that’s hard to refute. But it’s also silly to throw out the one bit of information we have in the matter; namely, that intelligence has successfully emerged on an ocean-covered planet with a thick atmosphere.

Still, there’s something to be learned by considering not just the evolutionary history of our planet, but its short-term future. We are now building digital devices that can process information at blistering speeds. Our computers double in capability on timescales of only a few years. It’s hardly outrageous to believe that we will successfully develop thinking machines within a handful of decades, or at most a century or two.

If that happens, these artificial sentients will quickly leave us behind. Unburdened from the slow and aimless process of Darwinian evolution, the machines will self-improve, and will do so in short order.

Full article: http://www.guardian.co.uk/commentisfree/2010/aug/24/alien-life-artificial-intelligence-seti