“With me the horrid doubt always arises whether the convictions of man’s mind, which has always been developed from the mind of lower animals, are of any value or at all trustworthy,” wrote Charles Darwin. “Would any one trust in the convictions of a monkey’s mind, if there are any convictions in such a mind?”
Although Darwin admits he wasn’t much of an abstract thinker, he could not shake the “inward conviction” that “the Universe is not the result of chance.” Unlike many who followed after him, he appears to have intuitively understood the paradox of combining naturalism with evolutionary theory: If evolution is a non-teleological process, it undercuts our ability to trust that we can form true beliefs and convictions.
To have trustworthy convictions, we have to have properly functioning noetic equipment (i.e., a brain, spinal cord, sensory apparatus, etc.) that can recognize reality. But can a strictly materialistic, non-teleological, evolutionary process produce such reliable equipment?
The philosopher Alvin Plantinga, one of the greatest thinkers of our era, thinks the answer is “no.” Although his argument is too complex and tightly argued to be adequately summarized, the basic outline of his case shows his point to be all but incontrovertible.
Plantinga claims, not that evolution is untrue, but that the truth of evolution is incompatible with the truth of naturalism. “As far as I can see, God certainly could have used Darwinian processes to create the living world and direct it as he wanted to go,” he argues. “Hence evolution as such does not imply that there is no direction in the history of life.”
What does imply that life is not directed, he adds, is not evolutionary theory itself, but the theory of unguided evolution: the idea that “neither God nor any other person has taken a hand in guiding, directing, or orchestrating the course of evolution.” For our purposes, we’ll call this view “evolutionary naturalism.”
Evolutionary naturalism assumes that our noetic equipment developed as it did because it had some survival value or reproductive advantage. Unguided evolution does not select for belief except insofar as the belief improves the chances of survival. The truth of a belief is irrelevant, as long as it produces an evolutionary advantage. This equipment could have developed at least four different kinds of belief that are compatible with evolutionary naturalism, none of which necessarily produce true and trustworthy cognitive faculties.
Take Zed, a prehistoric caveman. Zed is the first to cross the line over to homo sapien (his parents are very proud) and is the first to develop functioning noetic equipment that is the equivalent of our own. His equipment could produce four types of beliefs.
Option #1: Beliefs that are effects but not causes of behavior, whose truthfulness is irrelevant since they have no place in the causal chain leading to behavior. These beliefs are sort of the garnish on the plate of behavior; they are there but they have no purpose. For example, Zed may feel pain when he is bitten by a sabertooth and yet have a physiological reaction that is correlated, but not caused, by his pain sensation. Zed’s beliefs would be invisible to evolution and therefore can play no role in survival. (This view, called epiphenomenalism, is surprisingly popular among biologists.)
Option #2: Beliefs that are caused by and cause behaviors but whose truthfulness does not affect the behavior. For instance, Zed has discovered both language and singing. He notices that singing “UGGA BOO UGGAGA BOO” at the top of his lungs scares off birds and small animals. He believes that the words “UGGA BOO” have a magical effect on the animals that causes them to run away in fear. The words, of course, have no effect on the animals. It’s Zed’s horrendous voice that is scaring them away. (This view, called semantic epiphenomenalism, is surprisingly popular among philosophers of mind.)
Option #3: Beliefs that are caused by and cause behaviors but don’t help Zed survive. For example, he could develop a belief that letting a sabertooth bite his brain will make the animal happy—which leads him to constantly be putting his head in the mouths of the great cats.
Option #4: Beliefs that are caused by and cause behaviors and have an evolutionary advantage. Zed develops a belief that letting a sabertooth bite his brain will make the animal happy—which leads him to stay far, far away from brain-eating animals.
But what are the chances that that this evolutionary advantage results from the belief being true? According to Plantinga, we have no reason to believe that it is necessary for a belief to be true in order to be advantageous.
Zed needs to act in certain ways to survive. For example, he needs to avoid the saber tooth tiger taking a bite out of his big brain. We’ll call this “Tiger Avoidance Behavior.” Now Tiger Avoidance Behavior could be produced by Zed’s desire not to get eaten plus the true belief that Tiger Avoidance Behavior will increase his chances of not having his brain eaten.
The problem is that Tiger Avoidance Behavior could also be produced by false beliefs. Perhaps Zed likes the idea of being eaten and wants to run toward the tiger, but he always confuses running toward with running away from tigers. His false belief actually aids, rather than hinders, his survival. Therefore, a belief could have a survival advantage and yet be false.
The point of all this is that Zed’s noetic equipment does not need to produce true beliefs for him to survive. This is true for all four types of belief unguided evolution can produce. Since this holds true for even the most basic survival behavior, it is especially true for abstract ideas —idea like “evolutionary naturalism.” Whether the idea is right or wrong is purely accidental. While it is possible that any particular belief can be true, it is not, from an evolutionary perspective, necessary that any beliefs be true.
If, as evolutionary naturalism claims, our noetic equipment might have developed in different ways, then a belief in evolutionary naturalism itself could be any of the four types of belief listed above. What is the likelihood that evolutionary naturalism has produced in us cognitive equipment able to reliably form true beliefs and know that they are true? Extremely low. Even then, we could never truly know that we knew the truth, because we would know our belief might merely be the most advantageous to us.
In order to accept the naturalistic evolutionary explanation for the development of our noetic equipment we have to be agnostic about its reliability. All we would really know is that it works for evolutionary purposes, not for the purposes of discerning truth from falsehood. Evolutionary naturalism, it turns out, is a self-defeating argument. If we believe the theory, we have no reason to believe the theory is true.