Eternity in six hours: Intergalactic spreading of intelligent life (2013)

Sure, but you then can't access the computronium, because communication is so bad.

Also, I wonder if good old-fashioned computing is interesting at all to a civilization that's had access to advanced AI and quantum computing for a while.

Like we haven't really figured out how to get an ML model to run on a quantum computer, or how to build a quantum-native computer (i.e. surface of a black hole, or some other way that doesn't rely on our current sense of quantum error correction), but I don't know of any physical laws that preclude it.

I'd bet if aliens invaded our galaxy, they'd go for the super black holes in the center, or some other resource beyond our use and understanding, not this random water planet on the edge.

This is a study of the feasibility of launching an intergalactic colonization wave (and its implications re: the Fermi paradox), not a proposal that humans should do that (it would be just slightly ahead of its time for that!), or a discussion of the ethics or higher-level utility of doing so. It would be refreshing to see someone discuss the things paper actually discusses. To use early-2000s terminology, the paper's future shock level is higher than that of most HN readers, leading to rather banal discourse.

In any case, I'm fairly sure the authors agree that sending mindless automata to colonize the universe doesn't seem like a great idea. Nevertheless some alien intelligence (including an Earth-based AGI) might find it a completely reasonable, even imperative, goal.

But sentient machines or uploads (assuming for the sake of this this thought experiment that they are possible)? That's a different thing.

Political will is part of the Fermi paradox. So are technical reliability and cultural stability.

The idea that you can just build a thing and send out a swarm and (slow) boom - you've colonised the galaxy, and all the adjacent galaxies - is hopelessly naive. To the point I'd call it stupid and silly.

Let's say you have a replicator thing that works. You send them out in swarms.

And then what? Some die, some miss, some are destroyed by accidents.

Some work.

But "a replicator landed and made some more" is not colonisation. Colonisation implies there's some kind of to-and-fro traffic, maybe trade, some kind of information exchange at a minimum.

And that implies the source civilisation has political, technological, and cultural stability, which can survive an incredibly slow diaspora.

Colonisation worked on Earth because it didn't take long to cross the Atlantic by sailing ship. Successful colonisers landed where humans already existed and trade was easy.

It doesn't work on interstellar, never mind intergalactic time scales, because nothing stays stable for that long. Not hardware, software, politics, or culture.

Nor, on slightly longer periods, biology. On much longer periods, geology, and eventually astrophysics, because stars change, and planetary systems aren't unconditionally stable.

So a colonising wave from a unified culture is an incredibly unlikely thing, not at all an obvious necessity.

When you zoom this far out, anything can look possible… or impossible.

This is the same fallacy, but taken toward rather than away from infinite possibility, that underlies things like the Club of Rome’s world models and their limits to growth thesis.

Zoom way out and the details disappear. Look only at aggregate statistics and extrapolate. Do this and you tend to get graphs that go to infinity (this paper) or to zero (limits to growth).

But the details are where things actually happen.

Also look up computational irreducibility, which is kind of another way of approaching what I’m getting at here. You can only treat details in aggregate for systems whose causality is strictly hierarchical. If one detail can change the whole system, every detail must be considered or a simulation is invalid.

Turns out that living systems are like this.

Yes, but this isn't what the paper is talking about.