Darwin's Doubt: The Explosive Origin of Animal Life and the Case for Intelligent Design

by Stephen C. Meyer

History happened once. And if Richard Dawkins is correct that “there is, after all, one true tree of life, the unique pattern of evolutionary branchings that actually happened,”11 then evolutionary history also happened once. Consequently, if we think of evolutionary trees describing the relationships of animal groups as hypotheses about an unobserved history (which is what they are), then having two or more conflicting hypotheses about only one history—the history that actually happened—means that we haven’t figured out what did happen. A widely used textbook on phylogenetic methods explains this: “The fact that there is only one true tree . . . provides the basis for testing alternative hypotheses. If two hypotheses are generated for the same group of species, then we can conclude that at least one of these hypotheses is false. Of course, it is possible that both are false and some other tree is true.”