The Mystery of Evolution

To give a real explanation in terms of natural selection is no trivial matter. Nobody doubts that natural selection takes place, but to try to nail it down is not easy. But I think close to half of our genes come from the mental transposition that they come from other species. So there's all kind of complicated processes going on in evolution of which natural selection is true in one. And these explanations are kind of both stories of more or less plausibility.