Critics of evolution (usually theists) often claim that "believers in evolution" maintain that Darwin's theory is responsible for absolutely everything. This straw man once again illustrates the theistic obsession with absolutes — Darwinism is responsible for everything, or it's responsible for nothing. (The theistic world is black and white: morality, for instance, is objective, absolute, unchanging and set in stone, or else it is an insubstantial figment of human imagination — nothing in between.) Pearcey's chapter provides examples early on, when she discusses the wider application of a naturalistic worldview:
This is wrong on several counts. Darwinism does not mean that "all our beliefs and values are products of evolutionary forces" — only some of them. Ideas do not "arise in the human brain by chance" — to suggest that they do in any significant quantity, is to suggest that the process of thinking is no more than a random synaptic cacophony — some of which might by chance be "useful". Clearly this is not so. As for pragmatism being "truth is what works", this is such a blatant oversimplification one hardly knows where to start with it. The entries on "pragmatism" in Wikipedia and the Stanford Encyclopedia of Philosophy might be worth a try. (Note that although Pearcey uses the phrase "natural selection" she seems confused as to how it operates. She appears to be suggesting that ideas can be inherited — in a kind of transcendental Lamarckism.)
At the foundation of these efforts, however, was a naturalistic approach to knowledge itself (epistemology). The logic went like this: If humans are products of Darwinian natural selection, that obviously includes the human brain–which in turn means all our beliefs and values are products of evolutionary forces: Ideas arise in the human brain by chance, just like Darwin's chance variations in nature; and the ones that stick around to become firm beliefs and convictions are those that give an advantage in the struggle for survival. This view of knowledge came to be called pragmatism (truth is what works) or instrumentalism (ideas are merely tools for survival). (p 82.)
Unfortunately the paragraph quoted above is only the fourth in Pearcey's chapter, and it effectively undermines and invalidates most of what follows it. It's an all or nothing argument, which, if you take it literally and find even one tiny flaw, the whole edifice crumbles. To use a favourite anti-naturalism ploy, it's self-refuting.