Wednesday, February 24, 2010

Self-Defeating Science: The Irrationality of Evolutionary Naturalism

The Preterist Podcast recently turned me on to an awesome podcast called "Say Hello to my Little Friend," otherwise known as the "Beretta Cast" (and corresponding blog). As a disclaimer, I don't agree with everything I've come across at the blog; for example, I don't believe in "soul sleep," but rather that the immortal spirit is in some sense conscious in Sheol awaiting the resurrection--primarily because I don't believe Jesus' parables were rooted in fantasy. Nevertheless, I've enjoyed what I've listened to so far.

I was digging through the archive and came across a series of episodes explaining something called "presuppositional apologetics." I had heard of this style of apologetics before, but knew nothing about it, so I gave them a listen and was blown away. I highly recommend you listen to this series as it presents some powerful arguments for the existence of God. Episodes 11 through 13--go, listen, now.

I was particularly impressed with the third and final entry in the series discussing a Christian philosopher named Alvin Plantinga and his transcendental argument against evolutionary naturalism. Plantinga argues powerfully (and irrefutably, I think) that atheists who believe in evolution are utterly lacking in reason for believing that their beliefs are true. In fact, it is immeasurably more likely that any of their beliefs is false given their own world view. As such, evolutionary naturalism can only be described as irrational. I'll do my best to summarize Plantinga's argument.


The question asked by this line of reasoning is as follows: How probable is it that our beliefs, assuming evolutionary naturalism, are reliably true? This is expressed as the p (probability) of r (reliably true) given ne (naturalism and evolution). So what is the probability of r? To some this may seem like an exercise in futility. How could we begin to answer such a question? The reality is, however, we can approximate an answer--and the answer might surprise you.

Let's frame the question more concretely. Let's assume for a moment that there is no God, and that the diversity of life we see today is the product of blind, random mutations taking place during reproduction, operated upon by natural selection, producing successively more complex organisms. This is evolutionary naturalism in a nutshell. According to this world view, our sensory organs (eyes, ears, noses, etc.) and the mechanisms by which information from those organs is transmitted, as well as our brains which process that information and our instinctive reactions to that information all developed over time through random mutations producing a survival advantage over one's peers.

According to this model, then, our beliefs are based on physiological structures and mental faculties which developed only because they made us more capable of surviving in our environment, without respect to whether or not those beliefs are true. Do you see the distinction? Undirected evolution through natural selection produces structures, faculties and beliefs which offer a survival advantage, whether those beliefs are true or not. The question remains, then: What is the probability of r?


We humans do not often take part in the useful practice of thought experimentation, but let's do that for a moment. Imagine another world with a creature similar to a human--we'll call it Bob--which developed over millions of years through undirected evolution. Like us, Bob has developed sensory organs, transmission mechanisms and a brain by which he perceives his world, and has formed or had passed down to him beliefs about reality. Let's take a closer look at some of these.

Bob's eyes, optic nerves and brain have developed in a peculiar way. His species' primary predator is a terrible, tiger-like creature, but when Bob lays eyes on it he sees a giant, flashing sign with a message saying (in his language, of course), "Run fast in the other direction to experience great joy!" His endocrine system simultaneously developed to secrete a tremendous feeling of joy upon running sufficiently fast and sufficiently far in the opposite direction from the predator, providing him with the sense of great joy his eyes promised him.

Now, the peculiar way in which Bob sees this predator, and the way his body reacts when he runs fast and far enough away, have provided him with a survival advantage over his peers. But is he perceiving reality correctly? Of course not. There are a seemingly infinite number of ways in which Bob might perceive reality that give him an edge over his competitors, but which do not correspond to reality in an accurate way, and only one which is truly reflective of reality (which might not be advantageous, incidentally). Thus, the likelihood that anything he perceives is real is infinitesimally small.

The same is true of Bob's beliefs. Let's say that the surface of Bob's planet is riddled with pockets of dense, reddish mud. Bob has never touched the mud, and is not aware that it is thick and would so slow him down that any predator would easily catch him. He has had passed down to him, however, the belief that the mud is an acid that will eat away at his flesh. Therefore, he avoids it like the plague, which benefits him as he obeys the sign he saw, unknowingly running from the predator he incorrectly perceived.

Like his sense of vision, Bob's belief is wildly inaccurate and in no way reflects reality. Yet, it affords him a survival advantage in that it causes him to steer clear of obstacles which would slow him down and allow him to be caught by the predator chasing him (which he doesn't know exists). Again, innumerable possible false beliefs exist which would give Bob an advantage, and only one which is true. The likelihood that anything he believes is true is immeasurably tiny.


Darwinists thus face an inescapable dilemma. Given evolutionary naturalism, what is the probability that one accurately perceives reality via one's senses? Little to none. Given atheism, what is the probability that one's beliefs correspond to reality? Little to none. The materialist is utterly devoid of justification for believing that anything he perceives, believes, or thinks he knows, is true. He exercises blind, warrantless faith that his senses accurately convey information, that his mind accurately interprets it, and that the beliefs he's formed and knowledge he's gained using those faculties are true.

Therefore, only if one believes there is a God is one justified in trusting in one's senses and beliefs. Indeed, one is justified in calling anything "knowledge" only if one believes a Creator made knowledge possible. Without a God, it is immeasurably unlikely that anything we sense, believe or think we know is trustworthy. But if a Designer fashioned the universe intending it to be able to be accurately perceived by its inhabitants, then we have reason to believe that knowledge is possible. True knowledge is only possible in a universe created by God.

No comments:

Post a Comment