Obviously, I think the first response is the best: the belief that we are beings with a tribalistic moral nature should just be abandoned. To those who take the second option, my reply is simple: given that human moralities exhibit great diversity and that some people's moralities are not tribalistic, why should we say that our moral nature is tribalistic? It won't do for the die-hard defender of the dogma to cite evidence of the pervasiveness of tribalistic moral attitudes and beliefs, whether the evidence is historical or based on experiments, even if it is cross-cultural, because any such evidence is compatible with the hypothesis that our moral nature (the moral mind) is neither tribalistic nor inclusive, but rather so flexible as to be capable of being expressed in either tribalistic or inclusive moralities, depending on the environment.
In other words, to take historical or experimental evidence of tribalistic moral attitudes or behavior as conclusive confirmation of the thesis that humans have a tribalistic moral nature is to ignore the biased-sample problem I noted earlier. If the human-constructed niches in which the moral mind can get expressed in inclusive moralities are rare and recent, then concluding that human moral nature is tribalistic because most human moralities have been like that would be no more cogent than concluding that water flea nature includes protective spines and helmets because most of the water fleas you happened to have observed has those features.
The tribalism dogmatist has recourse to one last desperate fallback position: he can admit that human moral nature sometimes permits nontribalistic moralities, but insist that tribalism nevertheless is part of the moral mind itself, and that it is therefore still accurate to say that humans have a tribalistic moral nature. For the reasons given in the preceding paragraph, I don't think that we should say that tribalism is an element of our basic moral psychology, part of the moral mind itself - unless we quickly add that the moral mind also includes the capacity for inclusion. But if one grants that the moral mind is tribalistic in that weak sense - that tribalism is only one aspect of a moral nature that also encompasses inclusion, the result is a Pyrrhic victory.
Why? Because the thesis that humans have a tribalistic moral nature loses its punch if one admits that humans can act contrary to that aspect of their nature because of another aspect of their nature, namely, their capacity for inclusive morality. Admitting that our moral nature is dualistic saps the force of the assertion that we have a tribalistic moral nature.
Suppose that the last-ditch tribal dogmatist rejects the idea that our moral nature is dualistic and in response to the obvious fact that some moralities are now inclusive says that inclusion nonetheless goes against our nature. That is, suppose that he still asserts that our moral nature is tribalistic, period, not tribalistic and inclusive. Allowing for our moral nature to be overridden - saying, in effect, that we can act "unnaturally" - dilutes the notion of the nature of a thing. And that greatly reduces the interest and importance of the grand thesis that we are beings with a tribalistic moral nature. It also renders that thesis incapable of yielding any significant predictions about the scope of potential moral change or the space of possible moralities.
What I have to say in this book will still be important even if you dispense with talk of human moral nature altogether and fall back to a weaker, much less sexy thesis: namely, that human beings, by virtue of their evolutionary history, are predisposed to behave in a morally tribalistic way. To say that they are predisposed to tribalism means that exhibiting tribalistic moralities is the default position for humans, the way they tend to act, even if that tendency is sometimes not realized because of cultural influences. Its the default position, because the disposition to tribalism is an especially powerful aspect of our moral psychology.
If you hold that much weaker thesis, you can read me this way: I will show that in spite of this supposed predisposition, some humans have developed inclusive moralities, moralities that are not merely aspirational but socially and politically potent; and I will explain how they did that. In other words, I'll explain how they moved from situations in which that supposed predisposition largely determined the character of human moralities to situations in which that predisposition was inhibited or overridden or neutralized to such an extent that they developed inclusive moralities. In explaining this shift, I will show that the supposed predisposition to tribalism is not nearly as severe as one might think. I'll show that inclusive moralities are likely to persist, if the environments that are friendly to them are sustained. Inclusive moralities are fragile, in the sense that the capacity for tribalism never disappears; but that doesn't mean that inclusive moralities are inherently unstable and doomed to decay.
Finally, let me emphasize that there is a way of interpreting the experimental and historical evidence of tribalistic moral attitudes and behaviors that is compatible with rejecting the Tribalism Dogma, even in its weaker forms. Such evidence can be explained without concluding that humans have an especially powerful, deeply rooted, biologically based predisposition to tribalism if we make the following reasonable assumptions: (1) the moral mind is highly flexible; (2) most humans have lived in environments in which that flexibility issued in tribalistic moralities; (3) culture has developed in ways that sustain tribalistic moralities, even when they no longer promote reproductive fitness and are no longer necessary for successful cooperation; and (4) some people have an interest in maintaining (or resurrecting) tribalistic tendencies and they have the ability to do so effectively.
Each of these assumptions is highly credible. [...]
From: Allen Buchanan (2020),
Our Moral Fate: Evolution and the Escape from Tribalism,
MIT Press, Cambridge: MA.,