Re: poly: Von Neuman Culture density functions(was: Is our lightcone is uninhabited except for us?)

From: James Rogers <>
Date: Mon Dec 15 1997 - 21:55:48 PST

At 12:04 AM 12/16/97 -0500, Perry Metzger wrote:
>James Rogers writes:
>> I am not so certain that we necessarily should have been crossed by a sub-c
>> Von Neuman culture. We don't have the slightest idea of what the
>> distribution of such cultures should be, but this information is necessary
>> to make such a calculation.
>I doubt it.
>Consider our own culture a few hundred years from now at most. Given
>nanotechnology, any individual member could launch Von Neuman machines
>that travelled out in all directions at near the speed of
>light. Anything that requires so few members of a culture to launch
>will almost doubtless *BE* launched. With billions of individual
>entities, what are the odds that no one will do such a thing?

I agree with you completely on this point. Someone, somewhere has almost
certainly launched a Von Neuman probes. Yes, we will most likely have the
capability ourselves within a short time. However, it also took us 5
billion years (+/-) to develop the capability from nothing.

>I doubt other cultures would be so different as to not do such a
>thing. Sure, most individuals might have self restraint, but just a
>few doing otherwise would make the world a different place. In the
>unlikely event that no individual member of a particular other culture
>doesn't do such a thing, I'd say that given two or three cultures out
>there the odds of none of them doing such a thing are vanishingly
>small. From an evolutionary standpoint the Von Neuman machines "win"
>after all -- they rapidly fill space.
>Given this, I find the idea that there might be advanced cultures in
>our light cone that have not sent Von Neuman machines in our direction
>exceptionally unlikely. Its possible -- I would never call it
>impossible -- but it is not likely.

My point is that a Von Neuman culture 5 billion light years away with a 4
billion year head start on us would still be outside of our experience. I
am not sure that the probability is all that high that Von Neuman cultures
are common enough that we would have a high probability of having one
within our light cone. The further back in space/time that we look, the
less probability that a Von Neuman culture could have existed.

Actually, if there *was* a Von Neuman culture within our light cone, they
would most likely already be here. It's like a deer jumping in front of
your car. By the time you see it, it is already too late to do much.
There may be thousands of Von Neuman cultures relatively local to our part
of universe, but if their development parameters were anything like ours,
they would almost certainly be outside our light cone.

-James Rogers
Received on Tue Dec 16 05:55:00 1997

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