For as long as cultures have had contact with each other, attentive observers have noticed the similarities between their respective myths. Today, scholars hypothesize that these similarities are either the result of accident, cultural sharing or diffusion, or a shared collective unconscious of symbols. But in his revolutionary book, The Origins of the World's Mythologies, E.J. Michael Witzel argues that there's a better reason for many shared features: common origin. Like linguistics or...