"Astrology can be tested by the lives of twins. There are many real cases like this: one twin is killed in childhood, in say a riding accident, or is struck by lightning, but the other lives to a prosperous old age. Suppose that happens to me. My twin and I would be born in precisely the same place, and within minutes of each other. Exactly the same planets would be rising at our births. If astrology were valid, how could we have such profoundly different fates?"