One of the principal doctrines of the Christian faith that sets it apart from every other conceivable religion is its doctrine of God. By this I mean our understanding of God as a Triune Being, and not our understanding of God as ontologically One (i.e. One in being). There are countless varieties of Unitarian Monotheism that exist and which some would like to say contain their own ontological monotheistic equivalents to our One True God, but these religious beliefs, while correct in ascribing all power and majesty and holiness to only one being, fail once we begin to scrutinize their conceptions of the Deity’s Being (all of which are mono-personal, and not, as the Bible teaches clearly, Tri-personal).
In his Dogmatic Theology, William G.T. Shedd explains why Unitarian Monotheism is ontologically impossible. His brilliant analysis and critique of Unitarian Monotheism not only demolishes all the varieties of forms that it presently takes (e.g. Judaism, Islam, Jehovah’s Witnesses, etc), but also contributes to the demolition of any attempts to construct a Pantheistic theology in order to make up for the ontological impossibilities Unitarian Monotheism entails. He writes:
“A subject [viz. God] without an object could not know. What is there to be known? Could not love. What is there to be loved? Could not rejoice. What is there to rejoice over?
And the object cannot be the created universe. The infinite and eternal object of God’s infinite and eternal knowledge, love, and joy, cannot be His creation because this neither eternal nor infinite. There was a time when the universe was not and if God’s self-consciousness depended upon the universe, there was a time when He was neither self-conscious nor blessed. The objective God for the subjective God, therefore, must be very God of very God, begotten not made, the eternal Son of the eternal Father.
…In the Christian scheme of the Trinity, the media to self-consciousness are all within the divine essence, and are wholly separate from, and independent of, the finite universe of mind and matter. The divine nature has all the requisites to personality in its own trinal constitution. God makes use of His own eternal and primary essence, and not the secondary substance of the world, as the object from which to distinguish Himself, and thereby be self-knowing and self-communing. God distinguishes Himself from Himself, not from something that is not Himself. This latter [i.e. something that is not God, viz. anything that He has created] would yield consciousness only, not self-consciousness.
…The divine self-contemplation is the beholding and loving of one divine person by another divine person, and not God’s beholding of the universe and loving and communing with it…. ‘The first love of God the Father to the Son is that which we call ad intra, where the divine persons are the object’s of each other’s actings. The Father knows the Son, and the Son knows the Father; the Father loves the Son, and the son loves the Father; and so consequently of the Holy Ghost, the medium of all these actings’ Owen : Sacramental Discourse, XXII.’”
This argument can, and should, be leveled against both Unitarian Monotheism and Pantheism in order to show that while the conception of an Almighty God is right and good, it cannot obtain ontologically if one denies the Trinitarian ontological constitution of that God. In other words, Monotheism only makes sense if it is Trinitarian Monotheism. In fact, we can go so far as to say that there is no true Monotheism apart from Trinitarian Monotheism. There is only One God who is, and He is eternally existent in Three Co-Equal Persons: Father and Son and Holy Spirit.