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Please do not quote without permission.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

be useful to refer to Robert Trivers’ (1971) work. We cannot exactly call him an evolutionary ethicist and he does not say anything explicit about whether morality is a derived product. Yet in his famous article of 1971, he puts forward an ingenious hypothesis for the origin of our intelligence and some of our social sentiments. These different capacities could have evolved to respond to the adaptive problems of our ancestors. Trivers starts from the observation that human beings who live in groups of individuals who interact regularly have much to gain by producing chains of interactions on a reciprocal altruism model. But from an individual point of view, it is also advantageous to benefit from the kindness of others without contributing anything in return. This fact has allowed the evolution of both tendencies to altruism and tendencies to opportunism. Natural selection has thus gradually developed a complex psychological system that assures the good functioning of cooperation in spite of the occasional tricks provoked by opportunism; it has given us the capacity to form friendships and to feel gratitude; it has given us cheater detection systems and the desire to punish cheaters; and, conversely, very subtle forms of dishonesty, hypocrisy and lying. This race of intelligence25 cheating and cheater detection is perhaps the origin of our (or at least the greatest subtlety of our cognitive capacities), as well as emotions such as guilt and indignation. Once all the necessary elements were in place, morality could emerge.

However, most followers of EE opt for the idea that morality itself is an evolutionary adaptation; in this way, they distance themselves from interpretations in terms of a derived product. Morality is thus a particular device, a ‘moral sense’, that has evolved precisely life26. because it allows us to respond to certain needs linked to community Divergence appears regarding how we should conceive precisely the phenomenon of morality and how to determine the processes that have led to its birth and its stabilisation in the course of evolution. One idea is that morality favours cooperation; provided that it works well, the latter is to everyone’s advantage. According to Robert Richards (1986: 289), ancestral human societies were composed of small groups of related individuals who regularly competed. This kind of environment was favourable for the evolution of altruistic impulses, which served the good of the community. In this way, a moral sense evolved among human beings: a set of inclinations and natural dispositions that committed individuals to act for the good of the community to which they belonged. More precisely, the moral sense is an innate attitude that evolved under the pressure of kin selection and group selection in the setting of small community life. Richards argues that it is thanks to these two mechanisms of selection that people are inclined to act for the good of the community, which is to say in an altruistic and, thus, moral, way. Michael Ruse (1984) proposes a similar explanation, but instead of kin or group selection, he prefers to give prominence to the idea of expanded reciprocity. According to him, the principle of reciprocity is anchored in our species and manifests itself in our conscience in the form of moral sentiments. Generally, Ruse believes in the existence of a moral sense, which is a sense of the good, of the bad, and of obligation. This is supposed to be written in our genetic material and to develop in the course of our ontogenesis. It is displayed in our emotions, which push us to act in an altruistic way, all the while instilling us with a belief in the objectivity of our altruistic convictions. So he writes:

I suggest that we humans have built in innately, or instinctively if you like, a capacity for working together socially. And I suggest that this capacity manifests itself at the physical level as a moral sense – a genuine, Mother Teresa-type altruism! Hence I argue – on purely naturalistic, Darwinian grounds –

10