The Cognitive Reliability Argument

• An argument first proposed some twelve years ago by philosopher Alvin Plantinga of the University of Notre Dame, who has since defended and revised the argument

• Plantinga seeks to show that Naturalism is self-defeating, and it is, therefore, irrational to be a Naturalist.

• What is Naturalism?– “[T]he belief that there aren’t any

supernatural beings – no such person as God, for example, but also no other supernatural entities, and nothing at all like God.”

Alvin Plantinga, Introduction to Naturalism Defeated?, p. 1

– Naturalism is, thus, the belief that nothing exists beyond the world that, in principle, can be studied by the natural sciences, i.e. biology, chemistry, physics, et al.

• Why is Naturalism Self-Defeating?

– Plantinga’s argument that Naturalism is self-defeating centers around the reliability of humans’ cognitive capacities.

– What are humans’ cognitive capacities?

• The mental and sensory capacities humans use to form their beliefs.

– What does it mean for humans’ cognitive capacities to be reliable?• Humans’ cognitive capacities are

reliable only if the content of a strong majority of the beliefs humans form using them are true, i.e. the content corresponds to the way the world really is.

– Plantinga argues that the probability that humans’ cognitive capacities, given Naturalism, are reliable, P(R/N), is either low or inscrutable (i.e. unknowable).

– Either way, Plantinga claims, it is unwarranted for anyone to accept as true any belief produced by humans’ cognitive capacities, including Naturalism itself.

– Accepting Naturalism, thus, gives one a good reason to reject it making it self-defeating.

– Since being self-defeating is sufficient for a viewpoint’s being irrational, Naturalism is an irrational viewpoint, and no one can subscribe to it without thereby becoming irrational himself.

– Plantinga’s whole argument rests on two claims.• Claim A: P(R/N) is either low or

inscrutable.– Actually, Plantinga claims that the

probability that humans’ cognitive capacities, given BOTH naturalism AND Darwinian Evolution, are reliable, P(R/N&E), is either low or inscrutable.

– He also claims (correctly, in my view) that Naturalism entails Darwinian Evolution or something functionally equivalent.

– Given this entailment, P(R/N&E) is the same as P(R/N).

– Thus, to simply matters, we will assume, along with Plantinga, that Naturalism entails Darwinian Evolution.

• Claim B: Given Claim A, it is unwarranted for anyone to accept as true any belief formed by humans’ cognitive capacities, including Naturalism itself.

• Plantinga’s argument for Claim A– Plantinga begins with what he calls Darwin’s

Doubt.• “With me, the horrid doubt always arises

whether the convictions of man’s mind, which has been developed from the mind of the lower animals, are of any value or at all trustworthy. Would anyone trust in the convictions of a monkey’s mind, if there are any convictions in such a mind?”

Charles Darwin, Letter to William Graham Down – July 3, 1881

– What, Plantinga asks, is the source of Darwin’s “horrid doubt?”• According to Darwin’s evolutionary

theory, humans’ present cognitive capacities, like every other capacity they possess, is the result of natural selection.

• Natural selection selects capacities, not for their ability to produce true beliefs, but for their ability to produce adaptive behavior, i.e behavior that results in the survival of the species.

• “[T]he fact that my behavior (or that of my ancestors) has been adaptive is at best a third-rate reason for thinking my beliefs mostly true and my cognitive faculties reliable.”Alvin Plantinga, “An Evolutionary Argument

against Naturalism,” p. 10

– Adaptive Behavior and Reliable Cognitive Capacities• In order for adaptive behavior to be a first-

rate reason for believing cognitive faculties reliable, this statement must be true:

– A being (species) displays adaptive behavior only if its cognitive capacities are reliable.

• Plantinga argues there is no reason to believe the italicized statement is true, especially given Naturalism.

• Epiphenomenialism

– For our purposes, we can take Epiphenomenialism to be the view that the content of beliefs plays no role in the production of behavior.

– “According to [the December, 1992 issue of] Time, a few years ago the eminent biologist J. M. Smith ‘wrote that he 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.’”

Alvin Plantinga, “An Evolutionary Argument against Naturalism,” p. 11

– Philosopher Robert Cummins goes so far as to call the position Smith enunciates the “received view” among Naturalists.

– As Plantinga points out, however, if feelings play no role in the production of behavior, including adaptive behavior, then neither does the content of beliefs.

– Since it’s the content of beliefs that is true or false, if what Smith claims is true, then a species’ displaying adaptive behavior is not a good reason to believe its cognitive capacities are reliable.

• The Efficacy of False Belief

– Let’s say that the “received view” among Naturalist is wrong and the content of beliefs does play a role in producing behavior.

– Is there any reason, Plantinga asks, to believe that the content of the beliefs that produce behavior has to be mostly true in order for behavior to be adaptive?

» No, says Plantinga.

» “Perhaps a primitive tribe thinks that everything is really alive, or is a witch, or a demon of some sort;

» “and perhaps all or nearly all of their beliefs are of the form: This witch is F or that demon is G; this witch is good to eat, or that demon is likely to eat me, if I give it a chance. Clearly, these beliefs could be adaptive while nonetheless false.”

Alvin Plantinga, “An Evolutionary Argument against Naturalism,” p. 10

» The Matrix» ALL of the beliefs possessed by

the people in the Matrix are false; yet, these beliefs produce adaptive behavior.

» These false beliefs cause them to lie in their vats of goo, oblivious to the truth, but, nonetheless, surviving.

» Indeed, as Morpheus points out, that’s the reason the machines feed them the false beliefs.

– The upshot of all of this is that Darwin’s “horrid doubt” is well-founded.• Given Naturalism, there is no good

reason to believe the “convictions of man’s mind” are reliable.

• This is so because the adaptive behavior displayed by humans provides no good reason to believe their cognitive capacities are reliable.

• A very large number of false beliefs will produce adaptive behavior just as well as true beliefs.

– Perhaps, adaptive behavior requires that a certain critical percentage of a species’ beliefs be true.

– Still, there is no good reason to believe that critical percentage comes anywhere close to the strong majority necessary to make the species’ cognitive capacities reliable.

– What’s more, complex (and interesting) beliefs, e.g. Naturalism, are very unlikely to be among the critical percentage of true beliefs necessary for adaptive behavior.

• Since a very large number of false beliefs produces adaptive behavior and there are many more false beliefs than true ones, one can argue the P(R/N) is low.

• The best one can say, given all of the above, is that the P(R/N) can’t be determine, i.e. that it is inscrutable.

• Plantinga’s Argument for Claim B– Given that P(R/N) is either low or

inscrutable, the Naturalist has a defeater for R (i.e. the proposition that humans’ cognitive capacities are reliable).

– A defeater is a reason to doubt or not believe a proposition.

– “Among the crucially important facts, with respect to the question of the reliability of a group of cognitive faculties, are facts about their origin.

– “[S]uppose I come to believe that I have been captured by Alpha-Centaurian superscientists who have made me the subject of a cognitive experiment in which I have been given mostly false beliefs [or suppose I believe I am trapped in the Matrix] . . . . [In either case,] I have a defeater for R. But to have a defeater for R it isn’t necessary that I believe that in fact I have been . . . captured by those Alpha-Centaurian superscientists

– “[or have become trapped in the Matrix]. It suffices for me to have . . . a defeater [for R that] I have considered those scenarios, and the probability that one of those scenarios is true is inscrutable for me. It suffices that I have considered those scenarios, and for all I know or believe, one of them is true.”Alvin Plantinga, Introduction to Naturalism

Defeated?, p. 11

– The Naturalist is in the same epistemic condition as the person possibly captured by the Alpha-Centuarian superscientists or the person possibly trapped in the Matrix.

– This is so because, for all three, the probability that their cognitive capacities are reliable (or, if you prefer, unreliable) is inscrutable.

– Thus, given Claim A, Claim B is also true.

• Final Points– Plantinga’s argument, assuming it is sound,

does not prove that Naturalism is false.– Rather, it proves that Naturalism is an

irrational viewpoint.– Naturalism, Plantinga believes, is Classical

Theism’s biggest intellectual competitor, at least in the West.

– So, while proving that Naturalism is irrational does not prove that Classical Theism is true, it does give Classical Theism a big boost.

– What’s more, the probability that humans’ cognitive capacities are reliable give Classical Theism, P(R/CT) is 1.

• “[A]ccording to [Classical Theism], we human beings have been created in the image of God. This means, among other things, that God created us with the capacity for achieving knowledge . . . .”Alvin Plantinga, Introduction to Naturalism

Defeated?, p. 2

• “Only in rational creatures is there found a likeness of God which counts as an image . . . . As far as a likeness of the divine nature is concerned, rational creatures seem somehow to attain a representation of [that] type in virtue of imitating God not only in this, that He is and lives, but, especially, in this, that He understands.”

Saint Thomas Aquinas, Summa Theologica I, 93, vi

– While Naturalism entails Darwinian Evolution, it is NOT entailed by it.

• Classical Theism is consistent with Darwinian Evolution.

• This is so because the random (i.e. unpredictable) genetic mutations that drive Darwinian Evolution can be caused, orchestrated, and arranged by God to result in the eventual production of human beings.