To appear in Heams et al. (eds.), Handbook of Evolutionary Biology (provis. Title), Springer.

Please do not quote without permission. This is not the final version

mechanisms (kin selection, indirect reciprocity etc.) have allowed the evolution of these strategies.

Thanks to the work of biologists, we have explanations for the emergence of highly social behaviours among animal species. What about the evolution of moral behaviour? From an evolutionary point of view, the latter appears to fall under the category of social behaviour requiring explanation that is similar to those mentioned above. On the other hand, in contrast to animals, human beings are able to partially free themselves from the influence of their genes. Thus we must be able to account for this fact. It would take too long to provide details of all the different explanatory models that have been proposed. I will limit myself to presenting a summary map of the terrain. Looked at in a very schematic way, two explanatory routes have been developed. The first route considers morality a by-product derived from one or more adaptations that have evolved in their own way. In contrast to the adaptations on which it rests, morality has not been selected because it has proved beneficial to the individuals who practise it. It is rather a phenomenon that has somehow emerged independently of its effects on the biological world. The second route involves claiming that morality is not neutral from the point of view of selection; in other words, morality has been selected because it responds to a need that has appeared in the course of human evolution. More precisely, it offers a selective advantage at the genetic, individual or group level (or several at the same time).

The authors who opt for the first solution (Prinz 2009, Rottschaefer & Martinsen 1990, Singer 1981) think that morality is a derived product that rests on a certain number of capacities (for example, understanding others’ mental states, putting oneself in another’s shoes, communicating through language), and on psychological tendencies and more specific behaviours that are the result of the effects of reciprocity or kin or group selection. Thus George Williams writes:

Ethical systems […] must have been produced indirectly by some sort of accident, the sort of thing that happens routinely in evolution. […] These [moral] motivations must arise from biologically normal attitudes favoured by kin selection and reciprocity, but have biologically abnormal manifestations in our abnormal modern environment. (Williams 1993: 229)

It is important to know that certain detractors of EE (for instance, Nagel 1979), in their attempt to reduce the impact of evolution on our moral activity as much as possible, defend a similar position; but the detractors try to reduce the number of these capacities by using very will24, vague categories, such as intelligence, reason or free and by not attempting to come up with an explanation of the evolution and adaptation of these capacities. In contrast, the most fervent defenders of EE break down and provide details of the set of capacities and psychological tendencies on which morality rests. For example, Chandra Sripada and Stephen Stich (2006) think that our moral activity ‘surfs’ on a number of important modules, psychological systems that have evolved to respond to particular ecological needs and that function in a relatively independent manner in relation to one another. Among these, there is the mechanism for norm acquisition, or the tendency to adopt the norms and behaviours of prestigious people. These authors even think that innate tendencies dictate the content of some of our norms, such as the disgust felt at incest. Between these two extremes, there is a whole range of authors who defend intermediary positions (among them, G. Williams, Rottschafer and Prinz). To explain the evolution of many of the elements on which morality rests, it can

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