In article . com,
Ian Parker wrote:

This is missing the point. The time from the beginning of the Universe,
to the formation of a technological civilization, should take the form
of a normal distribution (i.e. bell curve), as pretty much any other
natural process does, due to the central limit theorem. If our
civilization is average (i.e. by the Copernican principle), then the
mean of this distribution is somewhere around the present. That means
that about half of the civilizations that will ever arise, arose before
us; and half will arise after us.

You are indeed correct, but how do you know the distribution is
Copernican. Why not a race? A race to me seems eminanly logical but so
far nobody has commented on it.

It's implied in what I've written; somebody (or a very small number of
somebodies) is going to evolve a technological civilization first, and
by hundreds of millions, if not billions, of years before the average
civilization. They will then proceed to colonize the galaxy, with the
result that the vast majority of civilizations will arise to find
themselves in an already-settled galaxy. Call this a race if you like,
but it's an extremely unfair one, since most likely it will be over
before the #2 civilization even appears.

If a race is indeed true there are
consequences in terms of how we should act.

Like what? We're talking about things on the timescale of hundreds of
millions of years. What we do in the next century or two isn't going to
make any difference.

1) We need to know how close to us other civilizations are. We are
running 42km and we need to look back and see where the other
competitors are. A 1km telescope - figure admittedly pluced out of the
air.

This seems rather pointless. All indications are that there is NOBODY
else out there. So, either we're in some sort of nature preserve and
the ancients are intentionally hiding from us, or for some weird reason,
we happen to be the first, and the galaxy is ours.

2) We do need to build interstellar VN probes. This to an extent
represents the tape.

I'm no fan of VN probes. But we'll be out there ourselves soon enough,
if indeed the galaxy isn't settled already (as appears to be the case).

This is to some extent of the nature of a BTW. Genetic markers on
mammalian species show that the main mammal types evolved in the early
to middle Cretaceous. Fossils BTW are quite rare because fossilization
is a rare process. Genetic markers are in fact better in showing when
Evolution took place.

Thus the Cretacious/Teriary extinction was less relevant than has been
supposed up to now.

Still quite relevant, though. Whenever there is a mass extinction, it's
followed by an explosion of new species. All evidence I know of
supports the rough approximation that life in the Cretacious had gotten
stuck into a bit of a rut (a local maximum, in optimization terms), and
the impact event certainly knocked it out of that.

But of course, that makes a philosopher of science uncomfortable as
well. The odds of us, as a civilization, happening to be the first are
quite low.

In a race situation the odds are high. If we were not the first we
would all be Centurians. Alpha Centurians would have terraformed the
solar system, and we would be in a park on Earth ... if that.

Clearly, the park (if we're in one) extends beyond the Earth; we see no
signs of life anywhere in the solar system. Perhaps our whole local
cluster of stars is part of the park, or maybe it extends only to the
edge of our solar system.

However, I think the Copernican objection applies regardless. Why do we
happen to be humans, and not Centurians or whatever? If the galaxy has
been settled for hundreds of millions of years -- as would be the case
if we're not the first -- then any random observer would very likely be
one of that ancient race, not some simian on some backwater world that
still thinks digital watches are a pretty neat idea.

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