"Looking at the natural world and back through human history amply demonstrates to us the lessons of intervention."
"Human history is like a shadow over the world, drawing people backwards, just like your personal history is a shadow over you, drawing you backwards." 
- Marshall Vian Summers, The Ethics of Contact
- Greater Community Spirituality, Chapter 18: What Is Human Destiny?
The world: Humanity's home world
Interbreeding: History on Earth