Radi Khrapko wrote:
An answer to the Fermi's question, `Where are they?', is
presented. The answer is: we are alone because our Universe
is bad for a civilization. The combination of physical constants
does not need to be more fine tuned than is necessary to permit
one civilization and, since extreme fine tuning of the constants
is a very unlikely event, it is most likely that our Universe is
just good enough to permit development of only one
civilization. The alternative anthropic principle can be
formulated as follows: `It is most likely to observe a universe
in which civilized life is an extremely rare phenomenon.'

Astronomical and Astrophysical Transactions 22 (2003) 847-850

Radi Khrapko


Another way to say the same thing is: If civilizations are common then
the earth would have been colonized a long time ago and we (a
pre-starflight culture) wouldn't be here.

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