Ethics and Evolutionary Theory

Abstract

It has long been argued that sometimes, acquiring information about the origins of one’s beliefs removes or diminishes the justification for those beliefs that one would otherwise have had. Descartes, for example, claimed that the less powerful the Author of his nature, the more reason he had to doubt his own beliefs (1960 [1641]: 79). And the more specific worry that knowledge of our evolutionary origins might give us reason to doubt our own beliefs famously goes back as far as Darwin himself, who remarked in an 1881 letter that ‘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 any one trust in the convictions of a monkey’s mind, if there are any convictions in such a mind?’1 In contemporary analytic philosophy, two sorts of arguments that might reasonably be regarded as descendants of Darwin’s doubt have attracted a lot of attention. The first of these is Alvin Plantinga’s evolutionary argument against naturalism (EAAN), which first appeared in the early 1990s (see Plantinga 1993, 2000, 2011). That argument is intended to show that anyone who accepts both atheism and the claim that human beings are products of evolutionary processes has grounds to doubt the reliability of all of her cognitive faculties and hence has grounds to doubt all of her beliefs. Plantinga advanced this argument as part of a critique of contemporary naturalism; it attracted a lot of attention among philosophers interested in the contemporary debate between Christian theism and naturalism. Around or shortly after the time that philosophical discussion of Plantinga’s argument had waned, there was an explosion of interest in arguments concerned specifically with normative beliefs or with some specific subset thereof. That explosion was triggered by the 2006 publication of Sharon Street’s ‘A Darwinian Dilemma for Realist Theories of Value’ and Richard Joyce’s The Evolution of Morality. Street and Joyce both argue that recognition of the evolutionary influences on our moral beliefs construed in a certain way gives us reason to doubt those beliefs and hence removes (or at least significantly diminishes) whatever justification those beliefs would have otherwise had. Although Plantinga advanced his EAAN as part of a defence of Christian theism over contemporary naturalism, Street and Joyce advance their arguments in support of specific metaethical positions. Street argues that her Darwinian dilemma makes trouble for any realist metaethical view according to which moral beliefs are true just in case they correspond with attitude-independent moral truths. She further argues that a version of constructivism according to which moral truths are functions of certain human attitudes is not susceptible to the Darwinian dilemma. Her argument, then, is advanced in support of constructivism over realism in metaethics. Joyce, by contrast, advances his argument in defence of a certain sort of moral error theory.2 His contention is that if there are moral truths at all, then there are attitude-independent moral truths but that recognizing the evolutionary origins of our concept of moral obligation gives us grounds for doubting that we ever apply that concept correctly and hence any justification our moral beliefs may have had is undermined.3 In this article, I provide an overview of the contemporary discussion of ‘evolutionary debunking arguments’ (hereinafter ‘EDAs’) that was triggered by the work of Street and Joyce. My main aims are to provide rough characterizations of the EDAs of Street and Joyce, indicate some of the various ways that these EDAs have been understood by commentators together with the most prominent lines of criticism of these EDAs, examine one particularly interesting off-shoot of Street’s EDA and identify some interesting areas for future research.