Dividing moral questions into those of substantive ethics, what should I do, and those of metaethics, why should I do what I should do, the mechanistic/Darwinian approach has little novel to say at the level of substantive ethics. One possible exception is that it is doubted we have equal moral obligations to all humans indifferently. We have special obligations to our children and other family members, and more to our friends and our countrymen than to others. We have obligations to the starving poor in Africa, but charity begins at home. Metaethically, the Darwinian can offer no justification. That would be to violate the naturalistic fallacy, going from claims about matters to claims about values. For the Darwinian the world has not intrinsic value. This means that the Darwinian is a moral non-realist. It does not mean they have no substantive ethics, but that these are psychological not grounded in external supports, natural or non-natural (like Platonic forms or the will of God). We objectify morality, thinking substantive claims do have support, are objective, otherwise we would all begin to cheat and the whole system breaks down. Ultimately, however, face to face, Darwinism demands a dramatic rethinking of common sense and the assumption of the ages, at least in western civilization.

Reciprocity has roots that predate humans, and is something that is fundamental to the animal kingdom. Much of this behaviour is instinctive (i.e. attitudinal) – e.g. cats licking each other – but these actions may have served as the kernel for the development of more complex, deliberative forms of reciprocity. By common consent, however, although there are some examples of non-human primates and even other species arguably demonstrating a deliberative form of reciprocity and although we have much to learn about animal behaviours, a tendency towards more sophisticated forms of reciprocity that rely on memory and a sense of obligation is predominantly human. Indeed, the human talent for deliberative reciprocity and hence cooperation is an important explanation for why humans have been so successful at populating the planet and dominating other species. This urge to act reciprocally lies very deep within the human psyche. For instance, there is some evidence that very young children show tendencies towards deliberative reciprocity, and demonstrate some concern for a person’s reputation, which is crucial for the effective operation of indirect reciprocity.