Re: Re: Planetary SETI: What _should_ we be looking for? (fwd)

Robert J. Bradbury (
Wed, 28 Jul 1999 10:35:31 -0700 (PDT)

> wrote:

> I have no idea either, but I would suspect it's because of the whole "race"
> mentality that's been associated with space here on Earth (i.e. Apollo). I
> don't think the posts that cling so voraciously to nanotech (to the point of
> redefining what an interstellar voyage is for no sensible reason whatsoever)
> have much to do with aliens; instead, they're projections of what might
> happen to _us_.

In arguing against AI or Nanotech, you have to argue against convergent evolution. There are numerous examples on Earth for convergent evolution (eyes and wings for example), since the advantages they provide demonstrate strong selective pressures. I would argue strongly that since the "limits of physical laws" provide the ultimate constraint, the path for long-lived civilizations is to evolve to these limits. Since nanotech particularly and AI (within nanotech computational structures) seem to be at such limits, I would argue that most, if not all technological civilzations reach these limits. Is it feasible for technological civilizations to attempt things (such as interstellar colonization) before these limits? Yes, certainly. However, the period of time at these "immature" development stages, relative to the length of time at the "mature" development stages is brief, so we can expect a majority of activities to occur at the limits of convergent evolutionary paths.

When considering "what *might* happen to us", it is useful to ask "what *are* the limits", and are the barriers to reaching those limits short relative to galactic or planetary time scales?"