I will have to go back and read/listen to this book again to really grasp everything but even my first pass of it taught me a lot about human nature, society, and our impact on the world. We may have evolved a level of intelligence higher than other living things on the planet but along with that intelligence came narcissism. We like to think that we are special but really we are just a species of animal. We built cooperative groups to survive and thrive but as the groups grew larger it became difficult to maintain the cooperation so we had to spread out. Like a virus, we infected every continent. We can tell ourselves that we explore and find new frontiers because it is in our nature to always look for the next great thing. I'm not so sure about that, though. I think maybe we just get bored or don't feel special anymore once too many people join us at the frontier. Thoughts?