This suggests that various natural selection forces, including perhaps exposure to chemotherapy, fueled a Darwinian selection
process as the tumors adapted in ways that favored growth and propagation.
The difficult problem this poses for Darwinian theory is how to mesh the multifarious proximate efficient causes that constitute a process of NS with the 'evolutionary cause', the Darwinian selection
This study illustrates the power of Darwinian selection
with so much variation produced in such a short period of time.
So the prevailing argument has long been that, because we civilized humans have for the most part managed to insulate ourselves from the natural environment, to nurse our sick back to health, and to provide mates for nearly all persons among us, the march of Darwinian selection
had finally reached an impasse.
Chapter 4 ("The Eclipse of Darwinism") analyzes the apparent collapse of Darwinian selection
theory during the early days of the "genetical" revolution and the liberal Christian embrace of nonmaterialist models of evolution.
To imagine that Darwinian selection
mechanisms could have seized upon a series of small but immediately beneficial genetic variations to produce a species capable of producing a Newton or an Einstein works no better than explaining Shakespeare by such means (p.