Re: Many Fermis Revisited

From: Tim May <>
Date: Sun, 12 Jan 2003 18:06:25 -0800

On Sunday, January 12, 2003, at 05:38 PM, Russell Standish wrote:

> The key assumption here is whether advanced technological civilisation
> (such as ourselves) is easy or difficult on the timescale of the age
> of the universe (10^10 years).
> Assuming that this is difficult (contra to your comments below),
> solves the standard Fermi paradox (namely other advanced civilisation
> are too far away to have reached us yet, and probably too far away to
> ever
> reach us, unless the universe starts contracting again.
> So your Throgians are as good as mythical.

I cannot understand why you would say "contra to your comments below"
when in several places I discussed this issue of how common life is:

"... estimates of likelihood of advanced civilizations elsewhere. If we
are the only form of life in our timelike region of the universe, i.e.,
within a few billion light-years, then of course this makes the odds of
another receiver-builder nil."

"My hunch is that alien civilizations may well exist, but are not
abundant "

I made no assumptions of nondifficulty (to use your phrasing).

This is in fact why I picked the Thogians a few hundred million
light-years from us. Now perhaps you think advanced civilizations are
even rarer than in this example, there have not yet been any
civilizations reaching our level, except ourselves, anywhere within a
billion light-years or so of us. Arguing this one way or another was
not my point.

Rather, it is that the effects of MWI communication (or time travel)
would likely be enormous and that such a civilization would be expected
to expand and show themselves in the (likely) billion or more years
they would have had to expand, build Dyson spheres and other cosmic
artifacts, send signals, etc.

> This also implies that such technological civilisations are also
> rather diffuse within the Multiverse, _excepting_ of course those
> which share part of their history with ours (eg the Nazis which won
> WWII). We have some predictive power as to what those people would be
> like, since they will be similar to us.

I'm not following this at all. Why do you think that communication with
(or actual travel to) worlds is dependent on our ability to _predict_
things about them?

I can see an argument to be made that only close worlds can be
communicated with, and some folks have argued this, but this argument
was not made by you here.

> So, I for one, would not discount Hal Finney's point.

What I said was that the point that we have not yet built a receiver or
portal says nothing about what others have done. And if there are other
civilizations out there and building such receivers or portals is
possible, one would expect a fair number of them to have done so. Since
the implications of building such portals are, I think, enormous, I
would expect a civilization which has built such things to have
expanded even more rapidly through their part of the universe than
without such things.

--Tim May
Received on Sun Jan 12 2003 - 21:07:44 PST

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