G.G. Simpson's changing attitude towards quantum evolution

This paper conducts a study of the published responses to a key process – quantum evolution – in G.G. Simpson's paleontological masterpiece Tempo and Mode in Evolution (1944), with the primary goal of revealing the reasons for Simpson's changed views, as indicated in his next book Major Features of Evolution (1953), on the importance of quantum evolution. I argue that the primary force that drove this change was not pressure from other leading synthesis thinkers like Mayr and Dobzhansky but rather empirical paleontological considerations. I consider the implications this has for the supposed hardening of the synthesis as defended by Stephen Jay Gould and for our understanding of the status of paleontology in the post-synthesis period. I claim that paleontology's secondary status in the immediate post-synthesis period resulted from the internal workings of paleontology and not merely pressures from allied biological disciplines.