To play the role of "guy who links to a relevant wikipedia page" again, the conflict between the fact that we've seen no observations of intelligent life out th

To play the role of "guy who links to a relevant wikipedia page" again, the conflict between the fact that we've seen no observations of intelligent life out there and our estimates that our life is not unique is known as the Fermi Paradox (http://en.wikipedia.org/wiki/Fermi_paradox http://en.wikipedia.org/wiki/Fermi_paradox). Once again, you may already know this, but it will hopefully be interesting reading to someone else.