James R. Flynn, a researcher critical of racial theories of intelligence, repeated the arguments of Arthur Jensen about the second edition of "The Mismeasure of Man". Flynn wrote that "Gould's book evades all of Jensen's best arguments for a genetic component in the black–white IQ gap, by positing that they are dependent on the concept of "g" as a general intelligence factor. Therefore, Gould believes that if he can discredit "g" no more need be said. This is manifestly false. Jensen’s arguments would bite no matter whether blacks suffered from a score deficit on one or ten or one hundred factors." Rather than defending Jensen and Rushton, however, Flynn concluded that the Flynn Effect, a nongenetic rise in IQ throughout the 20th century, invalidated their core argument because their methods falsely identified even this change as genetic.