You're using logical fallacies here. Just becuase it's "natural" for us to kill each other, and fight over the remains doesn't mean it's right – or it benefits us. If everyone is out for themselves, then we are constantly trying to fight and outdo each other. If, however, we collaborated then we'd achieve more. This is because we'd be able to collaborate, and take advantage of the unique qualities all of us offer, meaning we could discover more and do better.