Samuel Bowles has argued that altruism came into being because of the necessity of self-protection from out-group hostility. We are kind to our family at the expense of other families, and kind to our friends to the exclusion of other nearby people, and kind to our tribe and countrymen to the exclusion of outside groups. There are many of these in-group versus out-group distinctions that might be made. There is a continuum going from animadversion, through neutrality to “genuine altruism” as defined by Jorge Moll, where there is no expectation of personal reward. This kind of extreme altruism is only exhibited by humans (and social insects) because it requires the social development of a human to the level of seeing other humans as like themselves or identical to themselves as with social insects.
As humanity becomes one entity, the nations become unified and the age-old antipathies evolve into brotherhood, as has happened in Europe, there arises a problem. If everyone is united there is no external enemy, and if there is no enemy there is no in-group to be loyal to, and with that there is no development of empathy and altruism. Perhaps that extreme form of society is not going to happen because people always seem to find reasons for joining into groups and thus creating out-groups. Once there are out-groups there is someone to hate. It seems even competing amateur flower-growing clubs find reasons to hate other flower clubs.
Will it ever be possible to form a unified humanity which will be willing to abide by some common rules? The most worrisome common problem is generating a balance of human population with the Earth’s ability to sustain us. That requires cooperation of all humanity, but a humanity of individuals who consider as identical to them some person whom they will never meet and who looks very different from them. Like an ant of a given colony considering other members of its colony as more than a brother, rather as a clone of itself, as identical to itself.
The organizing principle of most governments and other groups is defining the in-group and out-group, but if all humanity is one entity obeying one law, then who or what will be the enemy? It must become those members of the whole world society that are violating the common law, but the horror of that is that everyone else becomes suspect of being a violator. It becomes a society where everyone becomes the enemy and no one deserves the slightest empathy or to be the recipient of any altruism.
In a one-world society everyone becomes an enemy, and no one deserves altruism.