Reply #44: It sort of depends.

[JoeyT]

It hasn't worked that way for us, but we may well never get beyond the edge of our solar system for that very reason.
Some people argue that any civilization advanced enough to explore deep space would have long ago gotten past most of their warmongering and other remnants of tribalism simply because the technology required to explore deep space would make it far too easy to annihilate themselves. Civilizations that don't get past the fighting shouldn't make it that far. The drive to explore space could be lack of room on their home world, resources to better the species, or simple curiosity.

Even if they have a bit of a point, I don't buy the argument. It's too easy to imagine a thousand ways a civilization could get around it. (Collectivism, hive minds, etc.) They're also assuming that another species that may have evolved in a radically different environment would think like people do. There are a lot of factions on Earth that would gleefully end humanity (and everything else) all in one go if it would stop a hated enemy from winning a fight, but there's no reason another intelligent species would think that way. Especially if we weren't the first intelligent life they'd encountered. A planet that contained two intelligent life forms could easily produce a bunch of jingoistic psychotic warmongers that only explore the galaxy to cleanse it of life that isn't related to them.