Grabby aliens are advanced civs who change the stuff they touch in big visible ways, and who keep expanding fast until they meet each other. Our recent analysis suggests that they appear at random stars roughly once per million galaxies, and then expand at roughly half the speed of light. Right now, they have filled roughly half of the universe, and if we join them we’ll meet them in roughly a billion years. There may be far more quiet than grabby alien civs out there, but those don’t usually do much or last long, and even the ruins of the nearest are quite far away.

While I’ve so far avoided thinking about much war within this scenario, I’ve decided to go there now. So here we go.

First, consider quiet alien wars. Such quiet civs may have internal wars, but different civs rarely get close enough to each other for physical fights. Maybe more advanced ones would sometimes conquer less advanced ones via malicious messages, but I’m skeptical that such events are common. The rare civs who expanded long and quietly mainly to preserve a natural universe and prevent grabby origins within their sphere of control should share goals and thus have little reason to war when they meet. Furthermore, when grabby civs meet quiet ones, abilities would be terribly unequal, and so not much of an occasion for war.

What about grabby civs? After a few million years they’d probably reach near max possible tech abilities. Which I guess makes them pretty immune to malicious messages. But such civs and their parts might vary in how well they had used a shared origin to promote internal cooperation. And a lack of perfect cooperation would likely result in some internal wars. The higher the rate at which they spend a fraction of their fast-access resources to fight or prevent fights, the faster they’d use up such resources. As a result, such fast spending civs might only get resources for a long time if some of their resource sources, like black holes, only allowed slow extraction.

Long-distance ballistic directed energy weapons, which couldn’t be redirected along the way, would only be of use on targets whose locations could be predicted long enough in advance. As a result, grabby cis would usually ensure that the locations of important resources vulnerable to such attacks could not be so predicted. Similarly, they’d end or stay away from objects like stars that might be induced to explode by outside prods. Thus militarily-useful resources would likely need to maintain unpredictable locations and would need to be located quite close to where they’d be used. So conflicts would tend to be won locally by those with more military resources locally available near the point of conflict.

If grabby civs are not more able to or inclined to cooperate internally than with other civs, then each small part of such a civ should be similarly wary of neighboring advanced life, regardless of its civ of origin. In which case, the boundary at which different grabby civs meet might not have that much significance. Who wins each local conflict would mainly depend on their relative size, resources, level of internal cooperation, and local geography, but not civ of origin. On 100Mlyr and larger scales, this should add up to a pretty uniform picture.

However, what if at least some parts of some grabby cigs could use their shared origin to cooperate more strongly internally than they could with other grabby civs? In this case, they’d expect more conflict at the border where grabby civs meet, compared to at other locations. As a result, the cooperating units on both sides might then try to send resources to that border, in anticipation of such conflicts. And then a key question arises: just how fast is it feasible to move militarily useful resources?

Grabby civs expanding at half the speed might seem surprisingly fast, but this does seem roughly feasible given that they can afford to spend huge resources on speeding tiny seeds that can then use local resources to quickly grow exponentially into huge civs. Alas, no similar exponential strategy seems available to move resources from one place to another. If the resources required to accelerate resources to near the speed of light can be efficiently recaptured at a designation location, then perhaps resources could in fact be efficiently sent very far very fast. But otherwise, sending resources far fast (e.g., >2% of c) may only be possible at crazy high costs.

At the border between two grabby civs, imagine that one of the civs had better managed to tax internal regions to send more resources to that border from within that civ, and at a very rapid speed. In this case, then after a while the resources accumulated on one side of that border might be far larger than that on the other side. Then if the natural advantage of defense over offense were not too large, the stronger side might be able to initiate a war and take territory from the other side. And in fact this outcome might become so obvious that the losing side would be very sure to lose, and not even want to fight.

If merely threatening to attack with overwhelming force was usually sufficient to quickly rout the weaker side and win new territory, via induced surrender or flight, or if actual fights did not take too long or destroy too much of an attacker’s resources, then an attacker might continue to move forward into the other side’s territory at a rapid pace. And if that pace were on the order of 2% of the speed of light, that might be sufficient to completely take over all the territory of a neighboring grabby civ within the roughly hundred billion years remaining before the time when, it is now estimated, dark energy makes galaxy clusters disconnected, never more able to see or reach each other. Such attack threats might then be seen as existential risks to such a civ.

Putting this all together seems to me to create a nightmare scenario, one which might greatly worry many young grabby civs who take very long term views. And, importantly, they’d have to decide how scared to be of this scenario long before they had much info on each particular neighboring civ, or even on any other civs besides themselves. Thus fear of the unknown might push many such civs into paying huge costs to maintain strong governance able to heavily tax internal activity to fund the movement of large amounts of resources out to be ready for unknown future border conflicts. Resources which might be mostly wasted if two such well-prepared civs were to meet.

Thus the possibilities of (A) long term civ-level views, (B) cheap fast movement of military resources which were hard to convert back to civilian use, (C) a sufficiently low advantage of defense over offense, (D) within-civ governance strong enough to tax and transfer resources to the border, and (E) weak enough governance unable to prevent your side from fleeing or surrendering given overwhelming attackers, all of this together might induce the waste of much, or perhaps even the vast majority of, available resources. Resources that could instead be used to compute far more meaningful peaceful lives near where the required resources sat originally.

Also note that at the line-shaped borders where three grabby civs meet, all three might have equal resources. Even so, two of them allying against the third would gain an advantage. And if this were sufficient, they might together advanced into the third region, sharing the gains. After which, each of them might have a geometric advantage, partially encircling the other side where their border bends. The possibility of this ally advantage should induce grabby civs to try to seem more similar to each other, to induce others to ally with them.