[extropy-chat] What Human Minds Will Eventually Do

[Russell Wallace]

On 7/4/06, Eugen Leitl <eugen at leitl.org> wrote:
>
> You don't know this until the mutation happened. Computing
> phenotype fitness from mutation is not feasible in principle,
> given that you don't know what the others do.


Perhaps not in principle, but in practice people do it all the time - it's
called art and engineering. Yes it's still differential survival of
replicators, but - as a matter of empirical data, not just theory - the
dynamics are quite different from those of biology.

Where did 'hours' come from, kemo sabe?


A gram of smarts on a hundred ton probe (i.e. very little slowdown) over an
interstellar-range jump, check the maths yourself. This is actually an
unrealistically bad scenario, since in reality a probe with a payload people
think is valuable will have far more resources available for its
acceleration than one with a payload that's of no value to anyone except
itself.

I've seen data on microwave-irradiated carbon trus cloth sails being
> accelerable
> at 3 g. Phased-array microwave radiators with ~lighthour to ~lightday
> aperture could
> track this with enough luminosity (some 2 kK sail operation temperature)
> for
> months. Don't ask me for the math, do it yourself.


Oh, Starwisp. I did:

It requires huge, expensive infrastructure for launch, something that would
be the product of a mature civilization, not a lichen-equivalent dumb
pioneer (let alone a parasite-infested one!)

Starwisp dies to collision with hydrogen atoms long before it clears the
solar system let alone travels interstellar distances.

Even if you postulate unobtainium shielding, it decelerates due to said
collisions before it gets very far (mean free path of interstellar atoms is
something like a few light-hours, you need to go light-years).

Even if it somehow reaches its destination, it just flies past because it
has no way to brake (the above deceleration doesn't slow it down enough).

This does strike me as highly plausible. D. radiodurans does it for biology.
> Redundant encoding, diagnostics and constant rebuild in the background
> plus
> redudant probes results in effectively unkillable high-velocity probes.
> Your worst problems are dust grains (take out one probe) and heavy ion
> tracks. Notice that the microwave beam will spontaneously push a clean
> tunnel through the interstellar medium clearing the path ahead of you,
> and magnetic fields (perhaps frozen with a plasma shield) can deflect
> ionized particles sufficiently that it doesn't hit your payload with.


D. radiodurans can take a few megarad before it dies, that's not within
orders of magnitude of good enough for relativistic cruising without heavy
shielding. Plus you'll be losing atoms all the time to erosion, eventually
you'll just plain run out. I don't know whether microwaves will push stuff
out of the way, but even if so, they have long wavelength so the beam
diffracts away well short of the destination. Magnetic field generators of
that power level are massive. (Scaling laws are not your friends if you want
to use magnetic fields on a small scale.)

I don't think whether the sacrificial sail approach would work.


Even if it would, that means a long-term commitment to maintain and operate
Dyson sphere sized infrastructure at home. Again you're talking about a
mature civilization, not dumb r-strategist pioneers.

Antimatter-catalyzed
> fusion drive and antimatter drive would work.


Maybe. If so, you're talking about - again - huge investment and a massive
probe. (Again, scaling laws are not your friends if you want to use engines
like that on other than a very large scale.) And numerical analyses put the
maximum delta-v of such drives, even making very optimistic feasibility
assumptions, at no more than a few tenths of c.

Again you're assuming the probe is painted (you know where it is)


The acceleration beam will do that very nicely indeed.

and you can illuminate it with critical luminosity, and that the
> probe will make no attempts to shield.


*laughs* A Nicoll-Dyson laser could boil a planet to vapor at a hundred
million light years range, and no, that is not a typo. (See
rec.arts.sf.science for discussion and calculations.) Somehow the ability of
such a weapon to kill a minimum-mass ship (let alone a Starwisp!) is not one
of the things I lack confidence in :)

Viruses don't have bombs, yet kill people just fine. Guns and bombs don't
> wipe stellar systems; nukes are largely useless in space. Stealth and
> backstabbing
> work fine, guns and bombs, or no. Starvation works fine. Just because
> you're
> no longer scheduled to die it doesn't mean you can't die.


Numerical analyses indicate (again see rec.arts.sf.science) that stealth is
completely hopeless in space but nukes and lasers will work fine, so you'll
be looking at ranged combat where one side (along with some fraction of the
other side) will be vapor (and blow away on the solar wind) before
tooth-and-claw distance is reached.

They're not arbitrary at all. I've found several folks who've arrived at
> exactly the same conclusions in isolation.


Yes, I used to be one of them.

What precisely do you think is fishy with machine-phase? On the one hand,
> you seem to assume it's possible. On the other hand, you have a very
> selective view on the capabilities.


I think like nuclear energy, space travel and digital computers it will turn
out that it's possible and can do interesting things but isn't the magic
fairy dust its early proponents and detractors both portrayed it as.

Bzzt. Wrong answer. You have to focus on the branch with the outcome that is
> bad for you. Everything else takes care of itself nicely.


Oh well if _that's_ what you're looking for, I can certainly oblige. I did
mention I'm a pessimist, right? :)

Here's my prediction: We die long before getting anywhere near the tech
level required to make any of this anything other than pure science fiction.
The road is too long, life - the lives of men, the life of Man - too short.
As far as I can reckon, that's the most probable outcome.

It's not certain, though. The fat lady hasn't sung yet; we still have a
chance.

_If_ we keep moving forward. If progress meant certain extinction then
people might as well die at home as anywhere else, and if you convince them
of that then that's precisely what they'll do.

The reality, though, is that life is inherently unpredictable. I can't
predict the future of life, nor can you, nor can anyone else. If we live
we'll have problems, and we'll just have to deal with them as they arise.

I can, however, predict the future of death, and decide to try to avoid it;
and that is all of my purpose here.
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