The Evolutionary Argument Against Naturalism

Perhaps the most substantial challenge to the Christian worldview over the past century and a half, at least in the west, has been atheistic materialism. According to this view nothing that exists is composed of anything that is not composed of physical material. The existence of non-material objects such as souls, spirits, or God is an impossibility. This view became more plausible after Charles Darwin introduced a theoretical framework that could potentially explain the diversity of the biological world. If there are natural processes working within the physical or material world that could explain the world around us then the theoretical need for a non-material agent such as God becomes unnecessary.

One of the most interesting developments, at least in my mind, over the past few years has been various challenges to that evolutionary framework such as irreducible complexity, the probability of anthropic “fine tuning” etc. Despite these assaults, however, the orthodoxy of evolution by natural selection is essentially unchallenged orthodoxy within the scientific community. In addition to the questions raised by a minority of scientists there are also certain philosophical challenges against materialism that are perhaps more significant. Many of those philosophical challenges are refinements of very old arguments, some dating back to ancient Greece. There is, however, a very interesting argument best articulated (in my mind) by Alvin Plantinga that actually uses evolution as an argument against materialism. It is a form of argument known as reduction ad absurdum where a debater assumes some premise of their opponent and then reasons from that position to demonstrate a contradiction in the system or some other conclusion that the opponent cannot accept. When done successfully it is a very effective way to argue.

Plantinga uses this approach in his evolutionary argument against naturalism (materialism). The full argument can get a bit complicated and I am only going to give a simplistic and basic overview so for those who are interested in learning more you can hear Dr. Plantinga explain it himself in a 5 part series here.

The argument is essentially that in order to have a naturalistic or materialistic view of the universe one is likely to accept evolution because it provides an important (almost necessary) explanation for biological life and diversity. Evolution, however, provides a defeater for the materialist, however, because, if true, it is likely to result in a low probability that our cognitive faculties are reliable. Therefore, if evolution is true, the materialist has no basis for being confident that his or her processes for coming to true conclusions are reliable (thus undermining their confidence in materialism).  I will try to explain a bit more.

Evolution holds that over time certain characteristics that give a creature a survival advantage will be “selected” for and those that reduce that advantage will be weeded out. The theory relies upon the ability of creatures to survive and reproduce and pass on those characteristics to their offspring so certain abilities such as feeding, fighting, fleeing, and reproduction are the determinative factors driving natural selection. Only those cognitive faculties that lead to advantages in those behaviors (such as a frog being able to determine the correct location of a fly it wanted to catch) will be selected for in the evolutionary process. Other cognitive faculties, such as the ability to perform abstract thinking, are not as likely to be reproduced. Since evolution is blind and unguided then cognitive faculties, such as human reason, which have developed via evolutionary processes have a low probability of being reliable because evolution is concerned only with behavior and not with belief.

Therefore, a Christian has within his or her system a rational basis for believing that our minds are trustworthy because of the assumption that we are created in the image of God, who is Truth. Naturalists, according to this argument, however, have no such rational basis for believing that their minds are trustworthy because their assumption is that the primary forces which formed them were focused not on producing a mind that has true beliefs but rather on producing an organism that is effective at feeding, fleeing, fighting, and reproducing.

There have been many philosophers who have responded to Plantinga’s argument as it was first proposed in the early 1990’s and he has since reformulated it (as recently as 2008) but, as expected, the debate continues.