The traditional nature-nurture controversy concerns whether ethical norms and social practices depend on cultural influences on individuals and societies or whether they are based on the particular features of our nature. In this chapter, we argue that nature and nurture cannot be sharply distinguished, as some scientists have tried to do in the past. Evolutionary considerations lead us to conclude that facts about our nature and the ways in which we come to form cultural traditions are entrenched in evolutionary processes. Before turning to the issue, though, we thought it might be worthwhile to deal first with two possible misunderstandings.

First, when we claim that we are concerned with the “bases” of ethical norms and practices, we do not mean that we offer a precise account of the ways in which such bases are relevant for the explanation or the justification of ethics. In particular, we do not deal with the question whether ethical systems or moral norms can be reduced to natural facts or cultural facts.