Re: poly: Is our lightcone is uninhabited except for us?

From: Hal Finney <>
Date: Mon Dec 15 1997 - 13:58:45 PST

Perry Metzger, <>, writes:
> The colonization thread has reminded me of an old argument I've
> made. I suspect that there are no other intelligent lifeforms
> substantially more advanced than us visible in our light cone, because
> if there were, they would have already built Von Neuman machines that
> would have arrived and taken over our solar system.

This is a variant on the Fermi paradox, and it does seem difficult to
avoid the main thrust of the conclusion.

Some have suggested that lifeforms capable of spreading nevertheless
choose not to do so, but this contradicts evolutionary imperatives.

Others suggest that expansion has in fact occured, but that we don't
recognize it. But it is hard to believe that all manifestations of
their activity are invisible. We don't see aliens here on Earth, we
don't see them elsewhere in the solar system, we see no sign of them
on other stars in our galaxy, or in other galaxies. Whatever they are
doing, it must be such that they are not visible on all of these scales.
You'd almost need four different and independent explanations for why
we see no evidence of their activity in each case.

Received on Mon Dec 15 22:06:18 1997

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