si vis pacem, para bellum -- Anon Guest
[AN: According to my translator webpage, this means: If you want peace, prepare for war. I believe Sir Pterry (GNU) had much to say about that though the Patrician.]
Humans have said for centuries, for millennia, If you want peace, prepare for war. Given the number of concurrent wars happening anywhere on the planet during those same millennia, one can safely posit that they got this horribly wrong.
They also believed that space travel would bring about peace. In a way, they were correct. Once anyone with an ideal and a quorum of followers had enough to make a world in their own image, they did so. They left with high ideals and fertile dogma and were never heard from again. Much to the relief of everyone else who had to put up with them.
If the resultant deep-time colony was lucky, they would be found on the other side of their isolation as a culture with their own identity, morals, and traditions. Many just became graveworlds because the dogma was unsustainable.