From: Russell Standish <[EMAIL PROTECTED]>
> I've just finished reading "Extraterrestrials: Where are they?" by
> Zuckerman and Hart. It really scotches the idea that SETI might
> actually be successful, even though the Fermi paradox is a bit
> overdone "Any ET civilisation of substantial duration would have
> colonised the Galaxy by now. So where are they?"
> However, Gott raises an interesting point. Anthropic reasoning eg
> Doomsday argument really rules out galactic colonisation - at least
> for our reference class. It would appear that the Doomsday argument is
> in direct contradiction with the Fermi paradox. I am rather
> uncomfortable about this, and my preference would be to accept the
> Fermi paradox argument over the anthropic reasoning.
I must be missing something here. Isn't the obvious answer for both Doomsday
and Fermi that civilisations don't last long enough to colonise?
Standard responses to the Fermi paradox include self-destruction,
colonisation apathy, and clandestine spread in our area (for ethical or
scientific reasons). My own favoured explanation is simply that intelligent
life (not necessarily any life) is sufficiently rare (<1 per galaxy) that
visitations haven't happened yet. There are counters to DA.