One of the great things about arguments for gods and the supernatural, is that you can always look back at them and find new problems. Alvin Plantinga’s arguments are especially lovely in this regard. Having been recently been thinking of Wittgenstein’s private language arguments, it occurred to me that somewhere in there is a rebuttal to Plantinga’s evolutionary argument against naturalism.
The evolutionary argument against naturalism argues that if both evolution and naturalism are true, then we cannot trust our own rational faculties, and therefore cannot trust our belief that evolution and naturalism are true. The reasoning goes that naturalistic evolution does not specifically produce true beliefs, but rather produces adaptive beliefs. An adaptive belief does not need to be true, it just needs to produce adaptive behavior. For example, rather than believing that you should run away from a tiger because it will eat you, you might believe that you should run away from a tiger because that’s the best way to pet the tiger (Plantinga’s example). The number of false beliefs that produce adaptive behavior is much larger than the number of true beliefs that produce adaptive behavior. Therefore, most beliefs are probably false.
There are numerous issues with this argument, a few of which you might be shouting at the screen. From a scientist’s perspective, Plantinga appears to be ignorant of how evolution actually works. Evolution does not necessarily produce the most adaptive traits, certainly not immediately. If you have false but adaptive beliefs at one point in time, it is questionable whether those beliefs would continue to be adaptive when your descendants find themselves in slightly different environments. Also, Plantinga ignores that brain efficiency is an adaptive trait. I would imagine that a brain which produces true beliefs via reasoning is far more efficient than a brain that produces false but adaptive beliefs via some mysterious yet reliable process.