I consider whether evolutionary explanations can debunk our moral beliefs. Most contemporary discussion in this area is centred on the question of whether debunking implications follow from our ability to explain elements of human morality in terms of natural selection, given that there has been no selection for true moral beliefs. By considering the most prominent arguments in the literature today, I offer reasons to think that debunking arguments of this kind fail. However, I argue that a successful evolutionary debunking (...) argument can be constructed by appeal to the suggestion that our moral outlook reflects arbitrary contingencies of our phylogeny, much as the horizontal orientation of the whale’s tail reflects its descent from terrestrial quadrupeds. An introductory chapter unpacks the question of whether evolutionary explanations can debunk our moral beliefs, offers a brief historical guide to the philosophical discussion surrounding it, and explains what I mean to contribute to this discussion. Thereafter follow six chapters and a conclusion. The six chapters are divided into three pairs. The first two chapters consider what contemporary scientific evidence can tell us about the evolutionary origins of morality and, in particular, to what extent the evidence speaks in favour of the claims on which debunking arguments rely. The next two chapters offer a critique of popular debunking arguments that are centred on the irrelevance of moral facts in natural selection explanations. The final chapters develop a novel argument for the claim that evolutionary explanations can undermine our moral beliefs insofar as they show that our moral outlook reflects arbitrary contingencies of our phylogeny. A conclusion summarizes my argument and sets out the key questions that arise in its wake. (shrink)

True beliefs are better guides to the world than false ones. This is the common-sense assumption that undergirds theorizing in evolutionary epistemology. According to Alvin Plantinga, however, evolution by natural selection does not care about truth: it cares only about fitness. If our cognitive faculties are the products of blind evolution, we have no reason to trust them, anytime or anywhere. Evolutionary naturalism, consequently, is a self-defeating position. Following up on earlier objections, we uncover three additional flaws in Plantinga's latest (...) formulation of his argument: a failure to appreciate adaptive path dependency, an incoherent conception of content ascription, and a conflation of common-sense and scientific beliefs, which we diagnose as the ‘foundationalist fallacy’. More fundamentally, Plantinga's reductive formalism with respect to the issue of cognitive reliability is inadequate to deal with relevant empirical details. (shrink)

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. (shrink)

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. (shrink)

Two of the most prominent evolutionary debunking arguments are Sharon Street's Darwinian Dilemma for Normative Realism and Alvin Plantinga's Evolutionary Argument against Atheism. In the former, Street appeals to evolutionary considerations to debunk normative realism. In the latter, Plantinga appeals to similar considerations to debunk atheism. By a careful comparison of these two arguments, I develop a new strategy to help normative realists resist Street's debunking attempt. In her Darwinian Dilemma, Street makes epistemological commitments that ultimately support Plantinga's structurally similar (...) argument. If Street succeeds in debunking normative realism, I argue, then she also succeeds in debunking atheism. But atheism is a suppressed premise of the Darwinian Dilemma as well as a commitment of almost all normative anti-realists. If Street's argument entails theism, then the Darwinian Dilemma is internally incoherent and should be abandoned by almost everyone. (shrink)