Re: Goo prophylaxis (was: Hanson antiproliferation method?)

Nicholas Bostrom (
Thu, 21 Aug 1997 22:30:59 +0000

Anders Sandberg wrote:

> On Wed, 20 Aug 1997, Nicholas Bostrom wrote:
> > Does anybody know of any work about the feasibility of active shields
> > as a defense against a nanotech enemy?
> We know immune systems do a fairly good job against natural "goo",
> although at a noticeable price: it consumes a lot of energy, and we
> multicellular animals have evolved sex (with all its complications
> and further energy losses) to improve its chances.
> So I think active shields are feasible, it is just unlikely they will
> be perfect. In the future even our equipment might get colds... :-)


If we want to use the immune system analogy, the term "active
shield" is perhaps a little misleading. One thinks of some kind of
spherical wall, but is what you have in mind somthing that would
permeate the whole domain? If it's just a wall, might it not be much
cheaper to blow a hole in it (with (nuclear?) explosives) than to
rebuild it? Then nanites could be sent in and devastate the
unprotected interior.

If it's not just a wall then there is still the question of power
balance. I agree with you that biology gives us hope in this respect:
higher organisms can and do survive in an environment with naturally
evolved viruses and bacteria. We need to consider:

(1) What if the parasites were designed instead of evolved? (Design
is better than sex. Remember, just because we might think sex is
more interesting doesn't mean it's more plausible!) Perhaps the fact
that the defence would also be designed would conterbalance this

(2) What if new chemical reactions are introduced? Will complicated
higher organisms still be viable? Exactly what properties of the
system does this depend on? Does anybody have any idea of how to get
a handle on this problem?

Nicholas Bostrom