Grounding Reason: Evaluating the Compatibility of Naturalism and Rationality

Abstract

Naturalism is the belief that the physical world is the whole of reality, and because of this every event can be explained by a chain of physical and chance causes. However, philosophers like Lewis and Plantinga have noticed a point of tension within naturalism, or rather, with the inference that naturalism is true. Under the theory of evolution, the ability for humans to think developed over time as a result of physical forces that selected for maximum fitness—survivability and reproduction. As a result, any thought processes that occur are conditioned to produce helpful behaviors, not true beliefs. This is a major problem for the naturalist who would like to be able to believe that his thoughts are true. Any attempt to prove the likelihood of evolution producing true beliefs fails because doing so would necessitate the use of reason–an immaterial inference into the order of a thing–thereby providing circular justification for reason. The end result is that the naturalist is required to accept the reliability of his cognitive abilities without any logical reasoning for doing so, in other words he must make a leap of faith. In more technical terms, the naturalist's ability to reason is the result of a chain of dependent events and is not grounded in a metaphysical rational order. Under naturalism, it is impossible for the naturalist to come to know this order (if it exists) through evolution. This eliminates the possibility to know for certain if any beliefs are true, including the belief in naturalism.