• in their full-fledged human form, our moral adaptations are the result of selection pressures over linguistic arguments about tribal politics.

Is that known to be true? It seems like a possible story, but other such ideas feel likely without working - game theory, group selection, kin selection, all these sound good but do not truly explain why we feel moral. I do not want to convince myself of such a mistake unless it works in math as well as convinces.