The question that I was addressing in part 1—and before that in “Whence Fact, Theory, and Path?”—concerned a familiar threefold distinction between evolution as fact, evolution as theory, and evolution as path. The question is easy enough to state: Who thought of it first? But the answer is hard to discover. In part that’s because there are so many ways of expressing the point: a writer might talk about the “path” or the “course” or the “route” of evolution on the one hand, or about the “theory” or the “causes” or the “process” of evolution on the other hand. In part that’s because so many of those ways could be used not to express the point: a writer who is discussing “the theory of evolution” isn’t necessarily restricted to discussing only the causes or the processes of evolution. So far, the earliest articulation of the distinction I’ve discussed occurs in Principles of Animal Biology (1920), by A. Franklin Shull (above), which might have influenced Winterton Curtis’s use of it in his testimony for the Scopes trial in 1925.