The Triune God

One of the chief obstacles to understanding the triune God of love is the modern change in the notion of person. In the language of the fathers, person (persona, ύποστασις) means independent, individual subsistence. In modern times, however, there is the additional quality of self-consciousness, which is entirely lacking in ancient usage. If we are to continue using the notion of person in relation to God, we must be careful to realize that no implication of self-consciousness is present in its theological expression. There are not three self-conscious personalities in God but one divine self-consciousness confirmed in God's threefold being. There are not three separate wills in God but one will. There are not three minds in God but one mind. One divine energy pervades the three modes of being or persons. . . . There are not three personalities in God, there are are three "persons." One self-identical nature or essence exists in three individual persons.

Paul C. McGlasson, Invitation to Dogmatic Theology