Reasons to Believe

Is Evolution Rational?

The other day I read an article written by Alvin Plantinga, arguably one of the greatest living Christian philosophers, entitled Evolution vs. Naturalism. I had to read it over several times to fully appreciate his argument, but found it fascinating and well worth the effort. Basically, Plantinga presents another form of what has become known as the Argument from Reason, popularized by C. S. Lewis in his book Miracles and discussed more recently in an article by Victor Reppert.

Without going into all of the details (I recommend you read the article), the argument goes something like this:

Materialistic evolution is purported to be an adaptive mechanism that controls the development of life and guarantees the survivability of that life. In particular, the neurophysiological processes that make up a species produce behavior that results in a species more suited for survival. In this evolutionary view, these same neurophysiological processes also produce beliefs. But while natural selection rewards adaptive behavior, it does not care whether beliefs are true. Plantinga argues that a naturalistic process like evolution cannot be guaranteed to produce true beliefs, and he quotes several evolutionists who confirm this view. He concludes that naturalistic evolution is a self-defeating explanation in that it cannot guarantee the reliability of the reasoning processes that lead to it.

Plantinga’s argument rests on the claim that evolution doesn’t care if beliefs are true. Upon reflection, however, I am not convinced that this claim is strictly true. There must be some beliefs that are produced that affect behavior, so they are being selected for survival in the same way behavior is selected. If those beliefs are not true, then I would expect survivability to be impacted. Can the development of these behavior-affecting true beliefs then lead to the forming of processes that could produce other true beliefs that do not directly affect behavior and, therefore, are not in the survivability loop? I suspect that Plantinga would say it is this limited set of beliefs that he had in mind in the first place when he was making his case, and since they are not in the survivability loop, there is no guarantee they are true. So his argument stands.

What is the end of all this? In the words of Plantinga:

The obvious conclusion, so it seems to me, is that evolutionary naturalism can’t sensibly be accepted. The high priests of evolutionary naturalism loudly proclaim that Christian and even theistic belief is bankrupt and foolish. The fact, however, is that the shoe is on the other foot. It is evolutionary naturalism, not Christian belief, that can’t rationally be accepted.

Subjects: Logic, Naturalism

Dr. David Rogstad

Dr. Dave Rogstad received his PhD in physics from Caltech and worked over 30 years for NASA’s Jet Propulsion Laboratory. Though now retired, Dave continues to serve as an RTB board member and participates regularly in several RTB podcasts.