Knowledge – justified, true belief – cannot be produced by unreliable noetic equipment (brain, spinal cord, senses, etc.). If we believe that it is possible to obtain knowledge, we must believe that our noetic equipment is reliable, hence designed for the task of producing reliable beliefs. But if our noetic equipment is produced by blind, undirected forces, then our equipment is not reliable.
In other words, if evolution is true, then there is no reason to trust that our cognitive abilities actually work.
My intention is not to repeat the comment war that occured. Rather, I'm quite persuaded by this challenge to Carter's post: "Joe, here's the question I want answered: How do you know our noetic equipment is reliable? If you say, because it arose from a rational process, then you're assuming you're noetic equipment is reliable enough to determine that fact. Please explain why you're allowed to beg the question and I'm not."
It's actually rather simple. Assume Carter is begging the question here. Even if he is, he enjoys the freedom to do so, given that on his hypothesis, reliability of the senses is not a problem. His explanation is simple--they're designed. The naturalist does not enjoy this position. On what grounds are our noetic faculties reliable? On the fact that they evolved to be? If they evolved over time, then it seems the probability of their reliability is significantly lessened, if not destroyed. If the reliability of noetic faculties is a problem for anyone, it is a problem for naturalists, not theists.
My point is not to suggest this is a good argument but simply to point out that not all questions apply trans-hypotheses. Some questions are more forceful for theists than for atheists, and consequently the theist has a greater responsibility to provide reasonable answers to them--one thinks of the problem of evil as one example. The the question of evil exists, it is more easily explained on a naturalist hypothesis. The problem of evil is a problem for theists, not naturalists. However, the problem of the reliability of cognitive faculties is more properly a problem for naturalists, not theists. It's important in examining various worldviews to realize that not all questions apply equally to every worldview.
Matthew Lee Anderson is an Associate Professor of Ethics and Theology in Baylor University's Honors College. He has a D.Phil. in Christian Ethics from Oxford University, and is a Perpetual Member of Biola University's Torrey Honors College. In 2005, he founded Mere Orthodoxy.