Abstract

Evidence from biology and psychology suggests that our moral views depend on our evolutionary history. For example, if we humans would have evolved to live like hive bees, we would probably think very differently about moral questions such as whether we have a duty to care for our children. The findings from biology and psychology threaten to ‘debunk’ the justification of judgements about objective moral truths. Objective moral truths are always the same and they do not vary with our contingent evolutionary history, whereas our moral judgements do. It has been argued that we, therefore, cannot tell right from wrong. In my thesis, I investigate the epistemology behind the evolutionary debunking of morality. Evolutionary explanations of morality, I argue, do not imply that our moral judgements are false. This leaves the possibility that evolution undercuts our (alleged) evidence for our moral judgements. Our evolutionarily influenced moral judgements might turn out to be unreliable guides to the moral truth, just like sight is a lousy guide to the external world in bad lighting conditions. However, I show that as long as we have reason to initially trust our moral beliefs, evolution does not provide us with reason to give up our moral beliefs. If evolution undercuts our moral beliefs, evolutionary considerations must show that true moral judgements do not qualify as knowledge because moral judgements are not cognitive achievements but comparable to lucky guesses. The thesis thus answers how empirical investigations of morality might have justificatory implications and the findings are relevant for deciding whether new factual information can alter how we think about right and wrong.