To understand how Darwinism undercuts the very concept of rationality, we can think back to the late nineteenth century when the theory first arrived on American shores. Almost immediately, it was welcomed by a group of thinkers who began to work out its implications far beyond science. They realized that Darwinism implies a broader philosophy of naturalism (i.e., that nature is all that exists, and that natural causes are adequate to explain all phenomena). Thus they began applying a naturalistic worldview across the board–in philosophy, psychology, the law, education, and the arts.

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).

Labels: David C. Price