Naturalism Defeated

Alvin Plantinga is a Christian philosopher who has been arguing for Christianity since the 1960's. He has written numerous books and articles over the years with a special emphasis on epistemology, which is the branch of philosophy that studies the nature of knowledge, its presuppositions and foundations. From 1993 - 2000 he released three books on the topic of epistemology, culminating with the 2000 release of Warranted Christian Belief. But in the second book, Warrant and Proper Function, he proposed in that book a very cogent argument for the inherent problems with Naturalism and Evolution. Over the next few years he tweaked the argument and made it better, answered criticisms, and has put forth one of the best argument against Naturalism & Evolution. I will try to sum it up as best as I can, but please check online as the papers are still available. 

Take philosophical naturalism to be the belief that there aren't any supernatural beings and that we evolved from simpler life forms to complex, including our cognitive abilities. Naturalist Patricia Churchland writes:

"Boiled down to essentials, a nervous system enables the organism to succeed in the four F's: feeding, fleeing, fighting, and reproducing. The principle chore of nervous systems is to get the body parts where they should be in order that the organism may survive. . . . . Improvements in sensorimotor control confer an evolutionary advantage: a fancier style of representing is advantageous so long as it is geared to the organism's way of life and enhances the organism's chances of survival [Churchland's emphasis]. Truth, whatever that is, definitely takes the hindmost."

The problem begins from certain doubts about the reliability of our cognitive faculties, where, roughly, a cognitive faculty--memory, perception, reason--is reliable if the great bulk of its deliverances are true. How can we be certain that our cognitive faculties produce true beliefs given random mutation and genetic drift? Is it at all likely that our cognitive faculties  would have developed in such a way as to be reliable, to furnish us with mostly true beliefs? Darwin himself expressed this doubt: "With me, he said, the horrid doubt always arises whether the convictions of man's mind, which has been developed from the mind of the lower animals, are of any value or at all trustworthy. Would any one trust in the convictions of a monkey's mind, if there are any convictions in such a mind?"  Evolutionary theory as proposed seems to be more interested in how we behave rather than what we believe. 

Then he moves into the area of defeaters. This is basically a counter argument. Say you believe x and then later on you run across new evidence that defeats your previously held belief. N&E furnishes one who accepts it with a defeater for the belief that our cognitive faculties are reliable--a defeater that can't be defeated. But then this conjunction also furnishes a defeater for any belief produced by our cognitive faculties, including, in the case of one who accepts it, N&E itself: hence its self-defeating character. 

The area of defeaters is more complex than I have outlined here and the source of much debate. But I believe that Plantinga has answered the objections well to still give warrant to his original argument.