Donald Macleod points out that the Trinitarian Father and Son relationship is the archetype of the same human relationship. This insists that there is something fundamentally the same about a Father and his Son. The eternal Sonship of the second person of the Trinity is part of the basis for insisting upon the homoousion (“same substance”) expression. The Son is the exact representation and substance of the Father. Nor can the Father continue to be the Father apart from the Son, and likewise the Son is not the Son without the Father. They are same and yet their difference is simultaneously necessary. As an archetype of the human father and son relationship, this suggests that faithful fathers must see themselves in their sons. And sons must see themselves in their fathers. To put it more precisely, fathers must see themselves as their sons, and sons must see themselves in an important sense as their fathers. They must also see themselves as mutually dependent upon one another and mutually dependent in their role as father or son. This means that just as Trinitarian theology must always hold the three and the one together: the homoousion concept along with the relationship of Father to Son (one and two at once), so too, human fathers must understand themselves as their sons, for example treating their sons as they treat themselves. And at the same time, it is incumbent upon fathers to be fathers and sons to be sons for both coexist. Thus, as many have pointed out, all filial/paternal breakdowns are ultimately Trinitarian heresies, careening toward Arianism or Tritheism on the one hand or Sebellianism and Unitarianism on the other.