(answer to the question "Do you think that mankind has grown by learning from its mistakes ?")
Our civilization has been surviving for quite a few centuries and won't vanish overnight like the Maya's... unless someone decides to push that darn red button that is. I'd say mankind has grown to the point it became one civilization, and it has no choice but to learn from its mistakes. I don't think mankind has always grown by learning from its mistakes but I know it can't keep growing without it. The XXIst century is key at all levels (environment, economics, politics, religion, health, social divides...).
Such "positive" thinkers as Lobby Dick Cheney could dub Yugoslavia's collapse and the Rwanda or Darfur scandals the "last throes" of the old order (heck : some dictators have been "smoked out" even in Africa), but I'm not so sure. Ten-twenty years from now, we'll eventually have some notions of what can be achieved during this century.