Elsewhere, some have commented that game theory is inappropriate for modeling morality, it was not clear how evolution could have encoded social morality in our biology and cultural moral codes, and it was not clear that the science of morality has any useful social purpose. This is my response.

The science of morality studies the morality of interactions between people (social morality) as natural phenomena.  But what does it mean that social morality “is natural phenomena”? And how might mindless evolution have encoded this ‘morality’ in our biology and cultural norms when morality remains so puzzling to people? Here, in Part 1, I answer these questions regarding our ‘moral’ biology. Part 2 will answer these questions for cultural moral codes.

The foundations of this discussion are simple observations about cooperation (meaning engaging with others in a mutually beneficial activity) in our universe and the challenge all beings face to avoiding exploitation when they attempt to obtain the many benefits of cooperation.

In our universe, cooperation can produce many more benefits than individual effort. But cooperation exposes one to exploitation. Unfortunately, exploitation is almost always a winning short term strategy and sometimes is in the longer term.  This is bad news because exploitation discourages future cooperation, destroys those potential benefits, and, eventually, everybody loses, even the exploiters.

This is the cross-species universal cooperation/exploitation dilemma – how to obtain the potentially large benefits of cooperation without being exploited. All life forms in the universe, from the beginning to the end of time, face this dilemma. This includes people and our ancestors.

People’s biology makes them highly social animals who can justifiably be called SuperCooperators, Martin Nowak (2011). How did our distant ancestors find solutions to this tricky cooperation/exploitation dilemma, as they must have, for us to become super cooperators? I say tricky because solutions to the exploitation dilemma have been intellectually understood as species independent phenomena in only the last few decades due to advances in game theory.

(Note, however, that even though we did not intellectually understand these strategies until very recently, our biology has equipped us to use and intuitively recognize some of those solutions to the cooperation/exploitation dilemma for, at minimum, hundreds of thousands of years. Based on observations of our ape cousins, who appear to share less effective versions of this biology, our ancestors may have used and intuitively recognized some of them for millions of years.)

How did mindless evolution ‘discover’ and encode these solutions in our biology by biological evolution? And what are these solutions anyway?

Game theory shows there are many possible solutions to the cooperation/exploitation dilemma in the form of strategies. (Note the ultimate source of social morality is the nature of reality, NOT game theory. Game theory is only the tool by which we discover solutions to the cooperation/exploitation dilemma.) All such strategies start with sharing two necessary components, a preference to cooperate even when doing so risks exploitation, and punishment of exploiters. These strategies are the species independent natural phenomena that the science of morality shows underlies social morality’s universal function.

Consider how evolution encoded a preference to cooperate and punishment of exploiters in our emotions empathy, loyalty, guilt, shame, and indignation. Empathy and loyalty motivate altruistically cooperating with (sometimes meaning just helping) other people and indignation motivates punishing other people who exploit our, or other people’s, cooperation.

Together, these emotions motivate simple, often highly effective, cooperation strategies such as tit for tat: Cooperate when you first meet someone, then do whatever they did to you the last meeting, cooperate if they did but attempt to exploit them if they exploited you. This defines a simple social morality, the morality of interactions between people.

(Of course, people are innately capable of much more sophisticated strategies than simple tit for tat, such as judicial forgiveness, reputation based cooperation, and group punishment which are all normally part of social moralities and are confirmed to be usually evolutionarily stable strategies by game theory. Tit for tat is just a simple example of how morality strategies might be encoded.)

What about guilt and shame? Punishment of exploiters is required to maintain the benefits of cooperation in societies, but is tricky because it can set off cycles of retribution that destroy cooperation. However, our ancestors who internalized their group’s norms and felt guilt when they violated them, and shame when other people found out, were better cooperators and had increased reproductive fitness due to this highly efficient internal punishment of wrong-doing.

What about kin altruism, most powerfully exemplified as a mother’s natural altruism toward her offspring? What does this have to do with human social morality? Kin altruism is almost certainly the original ‘mother’ of our moral emotions of empathy and loyalty, which, later in our evolutionary history, were recruited to be motivating elements for cooperation between non-kin. However, this discussion will focus on morality between non-kin as natural phenomena. Social morality based on kin altruism as a natural phenomenon may be best discussed separately.

What about Jonathan Haidt’s cross-culturally universal foundations on which people make moral judgments: harm, fairness, freedom, loyalty, purity, and respect for authority? How were these foundational bases for our moral intuitions selected for such that we intuitively recognize in-group-cooperation strategies as moral? Moral judgments based on harm, fairness, and freedom motivate in-group-cooperation with no reference to out-groups.  In contrast, moral judgments based on loyalty, purity, and respect for authority motivate the other kind of in-group-cooperation strategies – strategies whose power comes from discriminating against out-groups. As Haidt has pointed out, liberals tend to focus on the first three, and conservatives more equally on all six.

Because moral judgments based on loyalty, purity, and respect for authority were so important to the survival of the small groups our ancestors evolved in, these moral foundations were selected to be highly emotionally motivating for group unity and cooperation.

On the anti-social side, ‘conservative’ politicians in the US and elsewhere commonly exploit these in-group verses out-group moral foundations by inciting false moral indignation against out-groups.

But these same moral foundations can be used for pro-social purposes. Understanding morality as natural phenomena should help us understand what kind of emphasis on each of these moral foundations is most likely to increase, for example, overall well-being. Specifically, how do we capture in a moral code the important motivational power of loyalty, purity, and respect for authority while avoiding the unfair, exploitive, and cooperation destroying norms so commonly produced by the necessary discrimination against out-groups?

That is, how do we fairly define between-group morality while preserving the powerful well-being benefits of feeling much more obligation to our family, our friends, and our country, than to other people’s families, friends, and countries? There may be much to be learned here that will be culturally useful.

Now consider implications for the social morality of other intelligent species. As natural phenomena in the form of strategies to overcome the universal cooperation/exploitation dilemma, social morality’s function is cross-species universal from the beginning of time to the end of time. But other species’ different biological and environmental factors may change which behaviors are relevant or irrelevant for increasing the benefits of cooperation in groups, thereby producing strikingly different moral norms. For example, if a species reproduces by releasing millions of anonymous eggs and sperm in water and the offspring then care for themselves, moral norms about the worth of immature members of the species could be very different from ours.

All species’ enforced moral norms may be in-group-cooperation strategies to overcome the universal cooperation/exploitation dilemma, but we can expect the diversity of actual enforced moral norms between species to exceed that between human cultures.