The amount of resources some society can gather increases with the square of time and linearly to its expansion speed. But life around here has an habit of expanding everything (including resource usage) exponentially with time.

There is a mismatch here that you are implicitly claiming that is solved for every space-faring civilization. Many people explicitly make this claim, what is reasonable, but it's not good to keep it implicit.

I think it's a cold war situation.

In the early years, sure, no problem. But conceivably the pace of resource utilization will increase as well. Eventually they will conflict. Worse, greedy civilizations would probably be selected for.

And how long before random differences and exponential growth mean the other side gets an overwhelming power advantage? Historically in human societies, that is essentially never a good thing.

Maybe civilisations will merge. I just had my double LOR'xin with extra pumpkin spice. Later I will resume work on my ansible station for the Y'norxa-Wallmart Corporation… hopefully I can push some lines of lox-lang to production today.

What if wars were waged for ideological reasons also? Beliefs, cultures etc.

Or just defensively. The US invaded Iraq because they might have had WMDs. Other planets might have WMDs too. And they might think we have WMDs. Doesn’t matter if any of the sides actually do.

> The US invaded Iraq because they might have had WMDs.

Be careful not to conflate public justifications with actual motivations.

The point is that public justifications are more important than actual motivations. Actual motivations can be enslaving other beings, ruling / mining an extra planet or just wanting to watch the universe burn. Motivations are already present because there are millions of motivations that map on to the same result - destruction of another group of living things. I'm pointing out that it's easy to find public justification as well.

It's also possible to do this unilaterally. China or any other country could also unilaterally decide to destroy another planet. And same possibility on the other side.

Motivations lead to the justifications.

The problem with interstellar warfare is, outside the "Dark Forest" concept of "kill everyone just in case", there aren't all that many motivations that seem to make sense.

Any interstellar species probably doesn't really need to steal planets, resources, etc.

If planets in the “goldilocks zone” are extremely rare and they want to “terraform” (xenoform?) those planets then thats a motivation.

1. That seems very unlikely, from what we've found so far. We'll know more as things like the JWST come online, but right now it seems like planets of all sorts are everywhere.

2. Any civilization capable of interstellar travel is likely not to care all that much about a narrow band of natural habitability. They've already solved harder problems.

I'm not sure its given that a civilization that has technology for interstellar travel is going to consider a planet that is suitable for life with little work to be roughly equivalent to a planet that is suitable for life with a lot of work. Its equally likely that they would be economical with their resources and consider a planet that is closer to the desired end state to be much more valuable than a planet that is much further from the end state.

This seems likely; both sides might see it as a prisoner's dilemma situation, where there isn't any basis for trust and it's safer to destroy the other civilization before they're destroyed themselves.

(I don't think Iraq was actually such a situation, but at least on the American side some influential decision makers may have believed that it was.)

On the other hand, you might have something more like a cold war situation, where both sides have the capacity to destroy the other completely or almost completely but not without an equivalent counterattack, and so both sides have much more to lose than to gain by striking first.

Not at all, first our population will never exceed 11 billion, and most developed countries are in a demographic crisis. There is no sign of this trend reversing anywhere.

Second, what does 'earth is full' even mean? We have vast swaths of 'useless' land, like arctic and desert. Cities/towns/anything cover like 1% of the world. It is easier to desalinate water / build cities and greenhouses in deserts than it is to move people to another planet. We could host a lot more people if we adopted some serious geoengineering and built greenhouses /ate less meat.

Thirdly, travel to another star system requires insane amounts of energy, and could only be done by civilisations that already have enormous space infrastructure and industry. In which case you build habitats like we build skyscrapers, you can terraform, etc. In that case you don't need or want to ship billions of people to another star system.

> Habitable planets are the ultimate scarce resource.

Are they? That was once a common belief, but recent results in extrasolar planet searching would tend to contradict it, or at least cast it into serious doubt.

> Once the earth is full we’ll have to find a way to move

Will we? It's quite possible we'll see humanity's maximum population within the next century. Malthusianism didn't really survive contact with modernity; it turns out that most people don't particularly _want_ to have fifteen children, and as countries develop their population tends to become self-limiting. Wholesale emigration off earth feels like a very unlikely solution to population pressure, especially given that society seems to be automatically solving it.

And if we have the energy to lift billions of people off earth, we also have the energy to massively increase population density. Food, in particular, is ultimately largely a question of energy; we typically grow it in fields today, but given super-cheap energy there are other options.

If we've got the technology to travel between stars, we've probably also got the tech to leave planets behind entirely, or to terraform, or to adapt ourselves to conditions.

The only logical path is to download our brains onto computers, which will happen before that point. Once that technology exists, that's the only form of life that will dominate. Robots, nano-machines and hyper-intelligences will blow easily damaged flesh with finite lifespans. Habitable regions would be massively expanded.

If we can live inside a computer and create our entire world what will be the motivation to explore the universe?

Because we'll need energy and resources to run the computers!

When you can figure out how to physically attach consciousness to a machine, get back to me

I understand the criticism but I think that moment will come LONG before we start effectively colonizing or terraforming the other planets. Id bet a LOT of money on that.

the only thing that matters is for it to look like the consciousness has been attached.

I've never forgotten the scene in the OSC short story "Fat Farm", in which the protagonist's mind has been copied to his clone, which clone has left the facility to "continue" to enjoy his fine life, and the protagonist realizes he hasn't thought about what comes next. The answer is grim.

A consciousness might awake in the machine, but it won't be my consciousness.

But for the consciousness in the machine, does that distinction matter at all?

I think about this a lot. The answer, I think, is No, the distinction does not matter.

The consciousness in the machine will think "Wow this worked!" and go on with life in the machine. The original consciousness (you) will say "well that was dull - look at that machine consciousness having all the fun inside the machine."

But now extend the metaphor. Is there really any difference - in your perspective as the original consciousness - between the consciousness in the machine (your copy) and the consciousness next to you? (Your wife, husband, friend, brother, or sister). Or the consiousness across the street? Or any other consciousness that's not you? Each has its own set of memories that gives it a sense of self. Each sees the world outward from its own perspective.

So really, is there any difference at all? Either they're all totally different...or maybe they're all the same......

We'll never know. This is inherently subjective. Philosophers might suspect zombies...

Who says habitable to us == habitable to hypothetical aliens?