We are never, ever getting out of this solar system, and there simply aren't all that many new places around the sun that can support human life in a self-sustaining way.
I agree with the first part of this statement, but what about building our own places to live; like giant space stations? We couldn't do that today, of course, but 300 years from now, who knows?
Further, humans don't seem to tolerate each other very well when it comes to sharing scarce resources.
Just a quibble, but from what I've been reading, we seem to do better at sharing when resources are scarce than when there is an over abundance. Admittedly, I'm talking about smaller groups of individuals. I'm not sure if that applies to whole nations.
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