Boileryard Clarke, an astute investment observer, wrote, Testing for empirical regularities is conceptually difficult because it is

Question:

Boileryard Clarke, an astute investment observer, wrote, "Testing for empirical regularities is conceptually difficult because it is really a two-hypothesis test. One test is related to the validity of the underlying asset pricing model, and the other test is related to the existence of the empirical regularity." What does Boileryard mean by this statement?