Phillip Johnson

Darwin on Trail
It is not difficult to understand how leading Darwinists were led to formulate natural selection as a tautology. The contemporary neo-Darwinian synthesis grew out of population genetics, a field anchored in mathematics and concerned with demonstrating how rapidly very small mutational advantages could spread in a population. The advantages in question were assumptions in a theorem, not qualities observed in nature, and the mathematicians naturally tended to think of them as "whatever it was that caused the organism and its descendants to produce more offspring than other members of the species." This way of thinking spread to the zoologists and paleontologists, who found it convenient to assume that their guiding theory was simply true by definition. As long as outside critics were not paying attention, the absurdity of the tautology formulation was in no danger of exposure. What happened to change this situation is that Popper's comment received a great deal of publicity, and creationists and other unfriendly critics began citing it to support their contention that Darwinism is not really a scientific theory. The Darwinists themselves became aware of a dangerous situation, and thereafter critics raising the tautology claim were firmly told that they were simply demonstrating their inability to understand Darwinism. As we shall see in later chapters, however, in practice natural selection continues to be employed in its tautological formulation. If the concept of natural selection were really only a tautology I could end the chapter at this point, because a piece of empty repetition obviously does not have the power to guide an evolutionary process in its long journey from the first replicating macro-molecule to modern human beings. But although natural selection can be formulated as a tautology, and often has been, it can also be formulated in other ways that are not so easily dismissed. We must go on to consider these other possibilities.