Plantinga’s Argument Against Naturalism 2

The Doubt Develops Part 1

Consistent with evolutionary biology, Churchland’s “principle chore” of the nervous systems “is to get the body parts [of the organism] where they should be in order that the organism may survive.” Survival, rather than the formation of true beliefs, is the chief aim of brain evolution. This includes the survival of the individual, species, gene, or genotype. Intuitively speaking, it is therefore highly unlikely that the production of true beliefs is a function of the nervous system.

If N represents metaphysical naturalism, E the human cognitive faculties that have arisen via evolution, and R the claim that our cognitive faculties are reliable, then the conditional probability that our cognitive faculties are reliable is given by:

P(R/N&E)

In this thesis, we shall development the argument that P(R), given N&E, is low or less than 0.5.

Contrary to intuitive derivation, there are some philosophers such as W. V. O. Quine and Karl Popper who claim that P(R/N&E) is fairly high. However, as Plantinga had argued, we have to consider “four mutually exclusive and jointly exhaustive possibilities.” This way, we can conclusively show the evolutionist that P(R/N&E) is indeed low.

1. Epiphenomenalism: Behavior is not caused by beliefs

The first possible relationship between beliefs (as conceived by the brain) and behavior is this: behavior is simply not caused by beliefs. According to epiphenomenalism, there is no causal relationship between beliefs and behavior. Beliefs, which are arguably some electrochemical phenomenon within the brain, are not biologically causational to the neurological activities which produce behavior.

It is notable that this particular view is popular amongst certain biologists and neurobiologists. For example, Time (December, 1992) reports that J. M. Smith, a renowned biologist, wrote “that he had never understood why organisms have feelings. After all, orthodox biologists believe that behavior, however complex, is governed entirely by biochemistry and that the attendant sensations - fear, pain, wonder, love - are just shadows cast by that biochemistry, not themselves vital to the organism's behavior . . . .”

If epiphenomenalism is correct, then evolution – which is concerned with survival of the organism – is not concerned with beliefs, which allegedly have nothing to do with the organism’s survival or survival-producing behavior. In other words, the production of beliefs is invisible to the forces of naturalistic evolution.

As an example, Harry is a hominid that exhibits the characteristics of epiphenomenal behavior. What he does has nothing to do with what he believes. He might believe that a tiger is a cute kitten that is fun to play with. Nevertheless, brain evolution has somehow selected a surviving species of hominids that reactively run away from tigers. Harry, despite his reflex running away from tigers, in fact believes that tigers are fun to play with. This lack of integration and interrelation between beliefs and behavior makes it highly unlikely that the cognitive faculties are reliable for producing true beliefs.

For this option, P(R/N&E) is inevitably low or less than 0.5.

2. Semantic Epiphenomenalism

The second option for us is that beliefs do have “causal efficacy with respect to behavior, but not by virtue of their content. Put in currently fashionable jargon, this would be the suggestion that beliefs are indeed causally efficacious, but by virtue of their syntax, not by virtue of their semantics. (Plantinga, Naturalism Defeated)” In other words, beliefs may have caused behavior in this option, but only by virtue of their electrochemical properties or syntax, and not via their content or semantics.

This view is popular amongst contemporary philosophers of the mind. If this view is true, then the behavior of Harry the hominid is caused by the neurobiological or electrochemical changes or properties of the brain, and not by the content of the belief itself. It subsequently follows that the semantic properties of the belief, be it truth or falsehood, are invisible to the forces of evolution. The conditional probability P(R/N&E) is once again low or less than 0.5 in this option.

As an example, suppose Harry has the belief that ferocious tigers are furry kittens that deserve to be cuddled. This belief has certain electrochemical properties and a certain pattern of neuronal firings that somehow lead to the flight of Harry from these allegedly furry kittens. Despite the inherently false semantic properties of his belief, the behavior is caused by the syntactic properties, which lead to Harry’s survival. Although Harry’s belief - by virtue of its electrochemical properties - has survival and therefore, selective advantage, the content of his belief has little significance or contribution to his survival instincts.

PS: To be continued. We shall continue with the other two options in the next post.