A nightwatchman on every probe: Superintelligent surveillance to prevent galactic anarchy

One utopian vision for space expansion involves a libertarian explosion of diversity, with everyone and their robot setting up different sorts of societies and governance structures.[1] We might call such a future ‘galactic anarchy’. On Earth, while there is anarchy between nation states, within a country the government enforces contracts, protects property rights, and provides for collective defence against external aggressors. A government that does nothing else (e.g. provide a social safety net) is Nozick’s ‘nightwatchman state’. Without a Leviathan to uphold the rule of law, we are left with Hobbes’s war of all against all. But in the cosmic future, time and space make it far harder to have a centralised Leviathan punishing violations ex post. Suppose an aggressor conquers an already-occupied galaxy. It may take millions of years for nearby galaxies to learn about this infringement and prepare a response. And whose job is it anyway to go and punish the aggressors? That might be difficult and costly, and all the nearby galaxies prefer to mind their own business while strengthening their defences. Any inter-galactic governance system that relies on observing and punishing wrongdoing across millions of light-years is doomed to failure. Justice must be swift. And swift justice must be local,[2] not from the next galaxy over. If space is defence dominant, each star (or galaxy) can self-govern in peace without much fear of being conquered or destroyed by a neighbour. Even so, there are three huge negative externalities that a single rogue star system could impose on the rest of the galactic community: Unconstrained expansion. In a free-for-all—where anyone can use whatever resources they can grab and defend—people could be incentivised to race as fast as possible to be the first to lay claim to as many resources as possible, even if this involves ‘burning the cosmic commons’ by wasting resources to accelerate more and more probes closer to lightspeed. It’s pretty unclear how significant this waste would be—how feasible would it actually be to quickly harvest most of the energy from a star to speed up probes or launch even more of them?—but in the worst case, this could eat up a lot of the possible value and favour the spread of ‘locust’ value systems that only want to acquire and consume resources. Galactic X-risks. Jordan Stone catalogues many (scientifically uncertain) possible ways that a reckless or omnicidal civilisation could drag all others in its lightcone down with it (the ‘vulnerable universe hypothesis’). For instance, it may be possible to trigger false vacuum decay, destroying all particles in a bubble expanding at light speed.[3] Hopefully physics does not allow for this. But it is possible that at technological maturity, rogue star systems or galaxies could destroy the universe. If so, retroactive enforcement and punishment won’t suffice. Suffering risks. A misguided or malevolent civilisation could create astronomical amounts of suffering, many orders of magnitude worse than e.g. factory farming on Earth. Given defence dominance, the rest of the universe may be powerless to intervene and punish, or even stop, this. Even if the chance of any given star system going off the rails in one of these ways is very low, across billions of galaxies each containing millions of star systems that are slowly diverging from their parent civilisations through cultural evolution and drift, it is a statistical inevitability.[4] There are also some big upsides that might be harder to achieve under galactic anarchy, such as long-distance moral trade. Suppose that Earl on Earth and Andy in the Andromeda galaxy agree that Earl will spend some resources on hedonium and Andy will spend some resources running copies of Earl. It will plausibly be difficult by default to verify that counterparties are holding up their end of the bargain (from space, compute running hedonium plausibly looks about the same as compute running Earl uploads, so it might be hard for Earl to be confident that Andy is actually running copies of him and not hedonium). And, even with verification, it might be difficult to enforce contracts from a distance, especially if there are time lags that make it slower to do a tit-for-tat strategy. Suppose that Earl received word that Andy was not running Earl-uploads, 2 million years later. Earl has been faithfully running hedonium for the past 2 million years, so even if Earl stops now, Andy has gotten a lot of value out of Earl. And it might take even longer to propagate the news that Andy is a cheat to all of Andy’s (potential) trade partners. Funding public goods is also difficult under galactic anarchy. Currently, these are funded by governments coercively taxing their populations and then voting on how to spend the tax dollars. It’s possible that there will be galactic-scale public goods—scientific research, defence against aliens, or setting aside resources for pursuing impartial moral purposes—a