If God is one and all three persons of the Trinity are God, how does orthodox Christianity adequately deflect charges of modalism and polytheism? In other words, if the Father is God and the Son is God, how is the Son not merely an appearance of the Father if there is only one God (monotheism). Yet if the Father and the Son are not transitory manifestations of God but coexist as distinct divine persons, how is orthodox Christianity not another religion of the gods?
Before trying to address this conundrum, it might be helpful to consider some implications of an ancient Trinitarian creed.
We may distill these catholic claims from the Athanasian creed:
1. The Father is God
2. The Son is God
3. The Spirit is God
4. The Father is not the Son
5. The Father is not the Spirit
6. The Son is not the Spirit
7. There is only one God
An apparent contradiction is in view:
A. f = g (premise)
B. s = g (premise)
C. f ≠ g (premise)
D. f = s (from 1 and 2, by the transitivity of identity)
Contradiction or Paradox?
It seems to me that these conundrums can be dealt with adequately by supplementing additional biblically informed premises alongside the ambiguous ones. Simply augment some of the abbreviated premises with more biblical truth and paradox disappears, yet without being able to uncover the mysteries of the Trinity. (The solution is rational but ought not to be considered rationalistic.)
Is, =, and the law of identity:
It should be noted up front that there is a semantic difference between is and =, for x is y in common parlance does not necessarily imply y is x. Whereas x = y always is equivalent to y = x. For instance, Jim is human obviously does not mean the same thing as human is Jim. However, in some instances, the word is can imply a bidirectional truth or equivalent identity. For instance, there is an equivalence between Joe Biden is the 46th POTUS, and the 46th POTUS is Joe Biden. All that to say, we must be careful to discern what is intended by the verb is. Sometimes the meaning is one directional (e.g., Jim is human), and at other times the meaning is bidirectional (e.g., Joe Biden is the 46th POTUS). In the latter sense, is can be substituted with equals (=).
With that appreciation in place, we can now observe an undisclosed disconnect from what x is, (found in 1-7), to what x equals, (found in A-D). The basis for the inference found in A-D is sufficiently vague, which I trust will become apparent below. In other words, what does it mean that the Father is God? Does it, also, mean that God is the Father?
Points 1-3 (which utilize “is”) may merely suggest that three distinct persons all share the one divine essence and occupy “the same divine space” (perichoresis). Moreover, there is a qualified difference between each of the three persons when they are individually identified as God. Accordingly, the word “is” ought not to be taken to imply strict philosophical identity (in a creed no less!) without having first defined “God”.
Points A-D that follow (which utilize “=” instead of “is”) either creates, or uncovers, confusion (and possible paradox). Points 1-3 and A-D must be nuanced, for 1-3 does not imply the conclusion of A-D, which entails not only an apparent contradiction but rather, in light of 1-7, an ambiguity that keeps it (A-D) from being either coherent or contradictory. A-D suffers from an improper inference from 1-3. It needs clarification in light of the creed. The creed is not saying anything like God is not God, or the Son is not the Son! Hence, we may with confidence accept 1-7 without assuming it entails the paradox or actual contradiction implied in A-D.
Vague terms lead to unreliable conclusions:
If by God we mean the triune God, then obviously it is false that any divine person is God (i.e., the triune God). For instance, the Holy Spirit is not the Holy Trinity. Consequently, 1-3 is clearly false if God as Trinity is in view.
If by God we mean a divine person among other distinct divine persons, as opposed to a notion of the divine person, then 1-7 is orthodox, and D’s: f = s is not implied, alleviating the paradox in view. In other words, if each person of the Trinity is a distinct divine person (e.g. D1, D2 and D3), qualifying each as God the Father, God the Son and God the Holy Spirit respectively, then the personal properties of each person undermine the transitivity maintained in A-D.
Implicit modalism put to rest:
Not only can God mean Trinity, which the Son is not, God can also mean the person of the Holy Spirit, which the Son is not. Finally, God can mean the person of the Father, which the Son is not. Accordingly, to say that “the Son is God” and the “Father is God” without further qualification can be equivocal, and if taken in light of the law of identity, (as inferred by A-D without defining God), implies modalism because identity is transitive. The Son and the Father would be one and the same person, which the creed does not imply.
We may say in a colloquial-theological sense the Father is God just as we may say the Son is God, as long as we have the biblical backing that an unshared personal property of the Father is that he is unbegotten while the Son is eternally begotten etc. Being distinct persons, there are differences of eternal origin among all three persons of the Trinity who are one in being. The Father is divine, but doesn’t exist apart from his intra-Trinitarian begetting of the Son. That to say, the Father is not God apart from being a distinct divine person of the undivided Trinity. These Trinitarian relationships are necessary and eternal properties of personhood, not essence (lest the Father is the Son etc). They undermine any serious charge of modalism.