"This generation is crucial; we have the resources to get mankind off this planet. If we don't do it, we may soon be facing a world of 15 billion people and more, a world in which it's all we can do to stay alive; a world without the resources to go into space and get rich... I don't think it will come to that because the vision of the future is so clear to me. We need realize only one thing: we do not inhabit 'Only One Earth.' Mankind doesn't live on Earth. Man lives in a solar system... Given [a] basic space civilization ... we'll have accomplished one goal: no single accident, no war, no one insane action will finish us off."
Jerry Pournelle, A Step Farther Out