If A is father of, then what you assert of A when you say that he is so is a relational property namely the property of being father of B; and it is quite clear that this property is not itself a relation in the same fundamental sense in which the relation of fatherhood is so; and also that, if is a different child from, then the property of being father of is a different relational property from that of being father of, although there is only one relation, that of fatherhood, from which both are derived.