Online research in philosophy

Plantinga's Evolutionary Argument Against Naturalism aims to show that naturalism is, as he puts it, ‘incoherent or self defeating’. Plantinga supposes that, in the absence of any God-like being to guide the process, natural selection is unlikely to favour true belief. Plantinga overlooks the fact that adherents of naturalism may plausibly hold that there exist certain conceptual links between belief content and behaviour. Given such links, natural selection will favour true belief. A further rather surprising consequence of the existence of such links is this: even if semantic properties are epiphenomenal, unguided evolution will still favour true belief.

Recent iterations of Alvin Plantinga’s “evolutionary argument against naturalism” bear a surprising resemblance to a famous argument in Descartes’s Third Meditation. Both arguments conclude that theists have an epistemic advantage over atheists/naturalists vis-à-vis the question whether or not our cognitive faculties are reliable. In this paper, I show how these arguments bear an even deeper resemblance to each other. After bringing the problem of evil to bear negatively on Descartes’s argument, I argue that, given these similarities, atheists can wield a recent solution to the problem of evil against theism in much the way Plantinga wields the detailsof evolutionary theory against naturalism. I conclude that Plantinga and Descartes give us insufficient reason for thinking theists are in a better epistemic position than atheists and naturalists vis-à-vis the question whether or not our cognitive faculties are reliable.

Alvin Plantinga titles the closing chapter of his book Warrant and Proper Function "Is Naturalism Irrational?" He answers that it is. More precisely, he claims that anyone who is aware of the epistemological argument that he presents in this chapter has an unavoidable reason to doubt the combination of naturalism (according to which there is no God as conceived of in traditional theism) and evolutionary theory (according to which our cognitive capabilities are the products of blind processes operating on genetic variations). But then, he says, anyone who still accepts these propositions is irrational because it is irrational to accept a belief for which one knows there are unavoidable reasons to doubt.

There are three major theses in Plantinga’s latest version of his evolutionary argument against naturalism. (1) Given materialism, the conditional probability of the reliability of human cognitive mechanisms produced by evolution is low; (2) the same conditional probability given reductive or non-reductive materialism is still low; (3) the most popular naturalistic theories of content and truth are not admissible for naturalism. I argue that Plantinga’s argument for (1) presupposes an anti-materialistic conception of content, and it therefore begs the question against materialism. To argue for (2), Plantinga claims that the adaptiveness of a belief is indifferent to its truth. I argue that this claim is unsupported unless it again assumes an anti-materialistic conception of content and truth. I further argue that Plantinga’s argument for (3) is not successful either, because an improved version of teleosemantics can meet his criticisms. Moreover, this version of teleosemantics implies that the truth of a belief is (probabilistically) positively related to its adaptiveness, at least for simple beliefs about physical objects in human environments. This directly challenges Plantinga’s claim that adaptiveness is indifferent to truth.

In Warrant and Proper Function Plantinga argues that his natural view of warrant is best understood within a supernatural ontology. A central reason why anaturalistic ontology cannot accommodate his version of natural epistemology is that it cannot explain the reliability of cognitive functions. He presents argumentsfor the following two conclusions: (1) that naturalism is probably false; and (2) that naturalism is irrational. He considers the latter to be his main argument. Theobjective of this paper is to refute Plantinga’s arguments for the conclusion that naturalism is irrational. I will demonstrate that given naturalistic evolution, we havereason to believe that it is likely that we would develop reliable cognitive theoretical faculties. As a result, a naturalist has sufficient epistemic ground to maintain the reasonableness of the view that her theoretical cognitive faculties are reliable and her theoretical beliefs true. It is, therefore, not irrational to be a naturalist.

In Chapter 12 of Warrant and Proper Function, Alvin Plantinga constructs two arguments against evolutionary naturalism, which he construes as a conjunction E&N .The hypothesis E says that “human cognitive faculties arose by way of the mechanisms to which contemporary evolutionary thought directs our attention (p.220).”1 With respect to proposition N , Plantinga (p. 270) says “it isn’t easy to say precisely what naturalism is,” but then adds that “crucial to metaphysical naturalism, of course, is the view that there is no such person as the God of traditional theism.” Plantinga tries to cast doubt on the conjunction E&N in two ways.His “preliminary argument” aims to show that the conjunction is probably false, given the fact (R) that our psychological mechanisms for forming beliefs about the world are generally reliable.His “main argument” aims to show that the conjunction E&N is self-defeating — if you believe E&N , then you should stop believing that conjunction.Plantinga further develops the main argument in his unpublished paper “Naturalism Defeated” (Plantinga 1994).We will try to show that both arguments contain serious errors.

In the final chapter of Warrant and Proper Function, Alvin Planting a presents an “evolutionary argument against naturalism” (where naturalism is the claim that there are no supernatural beings). According to this argument, the conjunction of naturalism and evolution cannot be rationally believed by anyone who understands its epistemic implications. In this paper, I argue that if Plantinga’s evolutionary argument is sound, it follows that (what I call) perceptive naturalists have no propositional knowledge. Since it is plausible that perceptive naturalists do have some propositional knowledge, I infer that the evolutionary argument (EA) is unsound. However, I conclude the paper with the suggestion that even if EA is unsound, it may still provide important insights about the epistemic shortcomings of naturalism.

In "Warrant and Proper Function" Plantinga argues that atheistic Naturalism is self-defeating. What is the probability that our cognitive faculties are reliable, given this Naturalism and an evolutionary explanation of their origins? Plantinga argues that if the Naturalist is modest enough to believe that it is irrational to have any belief as to the value of this probability, then he is irrational even to believe his own Naturalism. I suggest that Plantinga's argument has a false premise, and that even if his argument were sound there would be reasons for doubting whether the Naturalist should respond to it by abandoning his Naturalism.

Alvin Plantinga has argued that evolutionary naturalism (the idea that God does not tinker with evolution) undermines its own rationality. Natural selection is concerned with survival and reproduction, and false beliefs conjoined with complementary motivational drives could serve the same aims as true beliefs. Thus, argues Plantinga, if we believe we evolved naturally, we should not think our beliefs are, on average, likely to be true, including our beliefs in evolution and naturalism. I argue herein that our cognitive faculties are less reliable than we often take them to be, that it is theism which has difficulty explaining the nature of our cognition, that much of our knowledge is not passed through biological evolution but learned and transferred through culture, and that the unreliability of our cognition helps explain the usefulness of science.