The obvious choice, then, is to extend our notions of self-interest. For example, it would not occur to me to plead with you, “Don’t saw off your leg. That would be an act of violence.” It wouldn’t occur to me (or to you) because your leg is part of your body. Well, so are the trees in the Amazon rain basin. They are our external lungs. We are beginning to realize that the world is our body.