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WillowOne's Positions

Evolutionary Argument Against Naturalism

Form

Alvin Plantinga's argument (Warrant and Proper Function, 1993; Where the Conflict Really Lies, 2011):

  1. Natural selection selects for adaptive behaviour, not for true belief. A creature's beliefs can be false and its behaviour adaptive, provided the beliefs and desires are matched to produce the right actions.
  2. So if naturalism (N) and evolution (E) are both true, the probability that our cognitive faculties are reliable (R) is low, or at best inscrutable.
  3. Anyone who accepts N and E and sees this has a defeater for R: a reason to doubt that their faculties produce true beliefs.
  4. A defeater for R is a defeater for every belief those faculties produce, including the belief in N and E.
  5. Therefore the conjunction of naturalism and evolution is self-defeating and cannot rationally be held. Theism, on which God made our faculties to track truth, has no such problem.

The argument descends from Charles Darwin's "horrid doubt" (letter to William Graham, 1881) and from the Argument from Reason.

My Positions

  1. Premise 1 is false as a general claim. True beliefs are, as a rule, more adaptive than false ones. A creature that believes the predator is to the left when it is to the right is eaten. Plantinga's counter-examples (Paul, who wants to be eaten but believes running toward the tiger is the way to be eaten, and so survives) require belief–desire pairs whose falsehoods cancel exactly, and would have to cancel exactly in every new situation. A truth-tracking system is a single simple solution; a system of paired compensating errors is a vastly more improbable one, and selection does not find the improbable solution when the probable one is available. Jerry Fodor and Elliott Sober made this point in the first round of replies and it has not been answered.
  2. Reliability is not all or nothing, and the pattern of our unreliability is what evolution predicts. Our faculties are good at medium-sized objects, faces, and social threat, and bad at probability, large numbers, the very small, and anything we would rather not believe (Confirmation Bias, Survivorship Bias, Owens Tryptic of Ignorance). Science is the set of practices built to correct the known failures. Naturalism plus evolution predicts this profile exactly. Theism, on which God made the faculties, has to explain why he installed the biases.
  3. Beliefs cause behaviour, so selection acts on content. On any naturalist view I hold (Functionalism, Substrate Independence), the content of a belief is what it does, and what it does is what selection sees. The argument quietly assumes that content is causally idle, which is a dualist premise, and the same premise that the Argument from Psychophysical Harmony needs.
  4. The argument proves too much for its author. If evolved faculties cannot be trusted, the theist's cannot be trusted to evaluate the argument either, since the theist also has evolved faculties. And on Plantinga's own Reformed theology the faculties are damaged by the Fall and "the heart is deceitful above all things" (Jeremiah 17:9). A Calvinist should be the last person to argue that his cognition is reliable.
  5. We have independent checks, and so does everyone. Bridges stand, predictions come true, instruments agree with each other. Plantinga says that using one's faculties to check one's faculties is circular, and so it is, for everyone, including the theist who checks his faculties by a belief in God that those faculties produced (Münchhausen trilemma, Transcendental Argument). The question is not whether the circle can be escaped but whether the system is self-correcting, and the naturalist's is.
  6. "Naturalism" is a thesis about what exists, not a faculty. The argument treats the belief in naturalism as something produced by the suspect faculties and so defeated, but every belief, including theism, is produced by the same faculties. If the defeater is universal it defeats nothing in particular; if it is not, the argument has to say what is special about naturalism, and it does not.

Sources

  • Plantinga, A., Warrant and Proper Function (1993), ch. 12; Where the Conflict Really Lies (2011), ch. 10
  • Beilby, J. (ed.), Naturalism Defeated? Essays on Plantinga's Evolutionary Argument Against Naturalism (2002), especially the replies by Fodor and Sober
  • Fitelson, B. and Sober, E., "Plantinga's Probability Arguments Against Evolutionary Naturalism", Pacific Philosophical Quarterly 79 (1998)
  • Law, S., "Naturalism, Evolution and True Belief", Analysis 72 (2012)
  • Darwin, C., letter to William Graham, 3 July 1881

Also see