Marshall insisted that it was unrealistic to expect that the dGRNs of modern animal phyla would tell us about how dGRNs operated in the deep past. In response, Meyer pointed out that Marshall’s position reversed the requirement of the historical scientific method as pioneered by Darwin and Lyell, both of whom insisted that our present knowledge of cause and effect should constrain our theorizing about the evolutionary past. Meyer said that Marshall’s willingness to jettison that principle reflected his own prior commitment to a materialistic worldview. (Marshall had previously, in his review and in the debate, accused Meyer of allowing his theistic perspective and motivation to color his analysis of the evidence.)
Also, here’s a video series offering a chapter-by-chapter look at the book.
So if you really wanted to know why the Cambrian period is the deep-six for neo-Darwinism that Darwin always feared it would be, you have plenty of resources.
By the way, don’t expect any of it to change the minds of Darwin’s followers; their minds don’t change, they just retire on the job.
The real forces that bring about evolution are still to be found, and the quest seems now to be anyone’s but theirs.