Hamilton’s untestable rule construes a subset of human relationships, in which an individual behaves constructively towards a relative. A different subset of human relationships is one in which an individual behaves destructively towards a relative: other subsets are ones in which an individual behaves destructively and constructively towards a relative at the same time, or after provocation by the relative or with a rejoinder by the relative. And so on. Does Hamilton’s rule front social defensiveness about how internecine families can be, and about the degree to which relatives can inhibit offspring, who then act out the characterisations they have been given, with a reduction in their reproductive fitness?
Hamilton’s rule endures because of the numinous tendencies of humans.