In order to greatly reduce X-risk, design self-replicating spacecraft without AGI

tl/​dr: If we’d build a working self-replicating spacecraft, that’d prove we’re past the Great Filter. Therefore, certainty we can do that would eliminate much existential risk. It is a potentially highly visible project that gives publicity to reasons not to include AGI. Therefore, serious design work on a self-replicating spacecraft should have a high priority.

I’m assuming you’ve read Stuart_Armstrong’s excellent recent article on the Great Filter. In the discussion thread for that, RussellThor observed:

if we make a simple replicator and have it successfully reach another solar system (with possibly habitable planets) then that would seem to demonstrate that the filter is behind us.

If that is obvious to you, skip to the next subheading.

The evolution from intelligent spacefaring species to producer of self-replicating spacecraft (henceforth SRS, used in the plural) is inevitable, if SRS are possible. This is simply because the matter and negentropy available in the wider universe is a staggeringly vast resource of staggering value. Even species who are unlikely to ever visit and colonize other stars in the form that evolution gave them (this includes us) can make use of these resources. For example, if we could build on (or out of) empty planets supercomputers that receive computation tasks by laser beam and output results the same way, we would be economically compelled to do so simply because those supercomputers could handle computational tasks that no computer on Earth could complete in less than the time it takes that laser beam to travel forth and back. That supercomputer would not need to run even a weak AI to be worth more than the cost of sending the probe that builds it.

Without a doubt there are countless more possible uses for these, shall we say, exoresources. If Dyson bubbles or mind uploads or multistellar hypertelescopes or terraforming are possible, each of these alone create another huge incentive to build SRS. Even mere self-replicating refineries that break up planets into more readily accessible resources for future generations to draw from would be an excellent investment. But the obvious existence of this supercomputer incentive is already reason enough to do it.

All the Great Filter debate boils down to the question of how improbable our existence really is. If we’re probable, many intelligent species capable of very basic space travel should exist. If we’re not, they shouldn’t. We know there doesn’t appear to be any species inside a large fraction of our light cone so capable of space travel it has sent out SRS. So the only way we could be probable is if there’s a Great Filter ahead of us, stopping us (and everyone else capable of basic space travel) from becoming the kind of species that sends out SRS. If we became such a species, we’d know we’re past the Filter and while we still wouldn’t know how improbable which of the conditions that allowed for our existence was, we’d know that when putting them all together, they multiply into some very small probability of our existence, and a very small probability of any comparable species existing in a large section of our light cone.

LW users generally seem to think SRS are doable and that means we’re quite improbable, i.e. the Filter is behind us. But lots of people are less sure, and even more people haven’t thought about it. The original formulation of the Drake equation included a lifespan of civilizations partly to account for the intuition that a Great Filter type event could be coming in the future. We could be more sure than we are now, and make a lot of people much more sure than they are now, about our position in reference to that Filter. And that’d have some interesting consequences.

How knowing we’re past the Great Filter reduces X-risk

The single largest X-risk we’ve successfully eliminated is the impact of an asteroid large enough to destroy us entirely. And we didn’t do that by moving any asteroids; we simply mapped all of the big ones. We now know there’s no asteroid that is both large enough to kill us off and coming soon enough that we can’t do anything about it. Hindsight bias tells us this was never a big threat—but look ten years back and you’ll find The Big Asteroid on every list of global catastrophic risks, usually near the top. We eliminated that risk simply by observation and deduction, by finding out it did not exist rather than removing it.

Obviously a working SRS that gives humanity outposts in other solar systems would reduce most types of X-risk. But even just knowing we could build one should decrease confidence in the ability of X-risks to take us out entirely. After all, if as Bostrom argues, the possibility that the Filter is ahead of is increases the probability of any X-risk, the knowledge that it is not ahead of us has to be evidence against all of them except those that could kill a Type 3 civilization. And if, as Bostrom says in that same paper, finding life elsewhere that is closer to our stage of development is worse news than finding life further from it, to increase the distance between us and either type of life decreases the badness of the existence of either.

Of course we’d only be certain if we had actually built and sent such a spacecraft. But in order to gain confidence we’re past the filter, and to gain a greater lead to life possibly discovered elsewhere, a design that is agreed to be workable would go most of the way. If it is clear enough that someone with enough capital could claim incredible gains by doing that, we can be sure enough someone eventually (e.g. Elon Musk after SpaceX’s IPO around 2035) will do that, giving high confidence we’ve passed the filter.

I’m not sure what would happen if we could say (with more confidence than currently) that we’re probably the species that’s furthest ahead at least in this galaxy. But if that’s true, I don’t just want to believe it, I want everyone else to believe it too, because it seems like a fairly important fact. And an SRS design would help do that.

We’d be more sure we’re becoming a Type 3 civilization, so we should then begin to think about what type of risk could kill that, and UFAI would probably be more pronounced on that list than it is on the current geocentric ones.

What if we find out SRS are impossible at our pre-AGI level of technology? We still wouldn’t know if an AI could do it. But even knowing our own inability would be very useful information, especially about the dangerousness of vatrious types of X-risk.

How easily this X-risk reducing knowledge can be attained

Armstrong and Sandberg claim the feasibility of self-replicating spacecraft has been a settled matter since the Freitag design of 1980. But that paper, while impressively detailed and a great read, glosses over the exact computing abilities such a system would need, does not mention hardening against interstellar radiation, assumes fusion drives and probably has a bunch of other problems that I’m not qualified to discover. I haven’t looked at all the papers that cite it (yet), but the ones I’ve seen seem to agree self-replicating spacecraft are plausible. Sandberg has some good research questions that I agree need to be answered, but never seems to waver from his assumption that SRS are basically possible, although he’s aware of the gaps in knowledge that preclude such an assumption from being safe.

There are certainly some questions that I’m not sure we can answer. For example:

  1. Can we build fission-powered spacecraft (let alone more speculative designs) that will survive the interstellar environment for decades or centuries?

  2. How can we be certain to avoid mutations that grow outside of our control, and eventually devour Earth?

  3. Can communication between SRS and colonies, especially software updates, be made secure enough?

  4. Can a finite number of probe designs (to be included on any of them) provide a vehicle for every type of journey we’d want the SRS network to make?

  5. Can a fiinite number of colony designs provide a blueprint for every source of matter and negentropy we’d want to develop?

  6. What is the ethical way to treat any life the SRS network might encounter?

But all of these except for the last one, and Sandberg’s questions, are engineering questions and those tend to be answerable. If not, remember, we don’t need to have a functioning SRS to manage X-risk, any reduction of uncertainty around their feasibility already helps. And again, the only design I could find that gives any detail at all is from a single guy writing in 1980. If we merely do better than he did (find or rule out a few of the remaining obstacles), we already help ascertain our level of X-risk. Compare the asteroid detection analogy: We couldn’t be certain that we wouldn’t be hit by an asteroid until we looked at all of them, but getting started with part of the search space was a very valuable thing to do anyway.

Freitag and others use to assume SRS should be run by some type of AGI. Sandberg says SRS without AGI, with what he calls “lower order intelligence”, “might be adequate”. I disagree with both assessments, and with Sandberg’s giving this question less priority than, say, study of mass drivers. Given the issues of AGI safety, a probe that works without AGI should be distinctly preferable. And (unlike an intelligent one) its computational components can be designed right now, down to the decision tree it should follow. While at it, and in order to use the publicity such a project might generate, give an argument for this design choice that highlights the AGI safety issues. A scenario where a self-replicating computer planet out there decides for itself should serve to highlight the dangers of AGI far more viscerally than conventional “self-aware desktop box” scenarios.

If we’re not looking for an optimal design, but the bare minimum necessary to know we’re past the filter, that gives us somewhat relaxed design constraints. This probe wouldn’t necessarily need to travel at a significant fraction of light speed, and its first generation wouldn’t need to be capable of journeys beyond, say, five parsec. It does have to be capable of interstellar travel, and of progressing to intergalactic travel at some point, say when it finds all nearby star systems to contain copies of itself. A non-interstellar probe fit to begin the self-replication process on a planet like Jupiter, refining resources and building launch facilities there, would be a necessary first step.