Abstract

The natural evolution of ethics is commonly understood in terms of the development from the selfish struggle to survive, via prudent cooperation, to altruism. However, cooperation that is prudent in the sense of serving basically selfish interests is not really altruistic. Besides, Christian ethics should not identify morality with absolutely disinterested altruism. Self-interest is only selfish when it is disproportionate or unfair; otherwise it is morally legitimate. Therefore the natural evolution of ethics is better understood as the gradual diversification of the goods in which human beings have an interest. And evidently, whatever their origins, humans do have an interest in a range of goods, not just the preservation of their genes or their kin or themselves. Therefore the reductionist, Hobbesian assumptions about human motivation that game theory makes are empirically untrue of human behaviour in general, and so the range of cases to which it applies is accordingly narrow. Rather than using biology to interpret human motivation reductionistically, we should use zoology and anthropology to track the evolution of interest in diverse goods. The fact that eudaimonistic Christian ethics, as represented by Thomas Aquinas and Joseph Butler, has long recognised this diversity of human goods is one sign of its continuing explanatory power, and counts towards its truth.