It's an attitude of superiority. We are superior to the rest of life. The Book of Genesis says: 'Increase and multiply and have dominion over the birds of the air and the animals and so forth.' You run it; it's yours; do what you like with it. I don't know how old that text is, but it represents an attitude that probably really got going with the beginning of agriculture. Before that, the hunter-gatherers were gentler people than the agriculture.