[extropy-chat] The Drake Equation and Spatial Proximity

Keith Henson hkhenson at rogers.com
Wed Oct 25 04:24:14 UTC 2006

At 07:53 PM 10/23/2006 +0200, Eugen wrote:

>On Mon, Oct 23, 2006 at 12:32:12PM -0400, Keith Henson wrote:
> > 1.  We are the first (at least inside our light cone).
>Why do people have trouble buying this explanation? That we're
>in nobody's smart lightcone, I mean? It's perfectly simple and
>adequate, a single explanation for all our data, or rather, lack

It violates the Mediocrity principle.  There is an extensive article on 
this and its counter, the Rare Earth hypothesis, in Wikipedia.

> > 2.  Civilizations don't survive nanotechnology (singularity now) or if 
> they
> > do, they lose interest in the physical universe or (somehow) leave it.
>Let's say we're within the lightcone of all such cultures, let's say
>10^9 (a pretty small number, actually) of them. What is the chance that all
>of those evolve precisely along a very specific trajectory, which
>ends in termination (or clean exodus, for all practical purposes
>that's the same)?

It depends on shape of the manifold.  For all we know, all evolved species 
are subject to the same weakness.  So their fate could be like a ball 
tossed into a basin.  No matter where it starts it always winds up at the 
bottom.  Still, I agree with you on it being less likely that all of them 
would fail.  If we are the first, the future is unknown rather than deadly.

>Even a single one of them would be enough to take
>a giant spherical bite out of luminous universe (actually, I already
>argued why you can't observe these expansion spheres due to the anthropic

If you do, you better dust off the welcome mat.

>So all of them evolve exactly the same way, and all of them don't manage
>any noteworthy expansion (we've already sent out dumb space probes beyond
>this solar system), or sterilize their patch of the cosmic petri dish when
>they (silently) implode? Statistically, that's very improbable. Unless we're
>in the light cone of very few smart but suicidal critters, which is
>actually only a minor variation on 1.

It has some strange implications for Eliezer and the SI.

Keith Henson

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