There are other, albeit more far fetched, ideas about the situation. One I find interesting is that we are like a chick pecking away at our egg shell. As we ge

There are other, albeit more far fetched, ideas about the situation. One I find interesting is that we are like a chick pecking away at our egg shell. As we get closer to being multi-planetary do we get to be more or less warlike? Do we settle on one ruling class and everyone else in bonds, or do we settle on a shared bounty? Do we destroy the world that birthed us, or do we come to grips with our own needs and develop what we need to live in perpetuity on the world we started on? On a much larger scale it doesn't seem all that much different than the growth of a person from child, to teen, to young adult, and adult. And in those stages of growth the perception of the world and one's place in it changes. Some learn self restraint, others do not, Etc. Even before young people start to drive they get to point where doing stupid things can kill them. The theory I find interesting is that civilizations are out there watching and the history is that some civilizations "grow up" and survive, and others don't. Some do something stupid in their "teen years" and kill themselves off, some develop a personality that results in them doing something that kills them. Some make it through that and become adults with a reasonable understanding and nominal "acceptance" of the things one has to do to stay alive and be civil. Maybe when we're "old enough" as a civilization, and we certainly will have enough science to understand that other civilizations could exist and how. They will introduce themselves.