SETI and the Cosmic Quarantine Hypothesis

"If civilizations exist in our galaxy with levels of technology at least equal to our own, we might be able to detect some of them using radio telescopes. And if civilizations exist with technologies far in advance of our own, we might expect them to have colonized millions of habitable worlds in the Milky Way, and even to have visited our own planet. Yet there is no evidence in the astronomical, geological, archaeological, or historical records that extraterrestrial civilizations exist or that visitors from other worlds have ever been to Earth. Does that mean, as some have concluded, that ours is the only civilization in the galaxy? Or could there be a natural self-regulating mechanism that limits the intensive colonization of other worlds?" -- Steven Soter

Entire Article

[19-Oct-05 follow-up]

Here are some of my thoughts:
If I read his argument correctly, he was essentially saying that:
i) If intelligences capable of developing apocalyptic technologies continue to be colonistic they will eventually suicide themselves. His assumption is that colonistic behaviour is both aggressive and irrevocably conflict inducing.
ii) If intelligences capable of developing apocalyptic technologies cease to be colonistic they may survive, but at the cost of remaining local to their solar system of origin.
iii) Thus, a selectional effect is in place here, where the only true *advanced* intelligences that can exist in the Universe are a) non-colonistic and b) local to their solar system of origin.

He admits, however, that his argument is potentially non-exclusive; all it would take is just one successful civ to overcome this risk and the Galaxy is colonized in short-order. Moreover, a successful colonization attempt via Von Neumann probes would solve this problem, also.

And his argument is largely a sociological one. Using terms like "colonization" and "aggression" is a risky proposition at best when trying to infer the motives of extremely advanced intelligences living in socio-economic conditions radically different from our own (Kardashev civ types come to mind, as does Post-Singularity intelligences).

That being said, his mechanism for a Darwinian selectional effect against interstellar colonization is a provocative one and it's provided me with much food for thought.

Tags: SETI, Fermi Paradox, Space Colonization,