Christians who believe that Mary is the mother of God often employ a three-step argument that runs as follows:
P1: Mary is the mother of Jesus.
P2: Jesus is God.
C: Therefore, Mary is the mother of God.
It’s as simple as that, right? Some Protestants say, “Not quite!”
In his article, “There is a logical fallacy in the argument that Mary is the mother of God,” Protestant apologist Matt Slick argues that the above argument involves the fallacy of equivocation, which is when a word, or words, changes meaning within an argument.
Which word does Slick think is being used with different meanings? God. He writes,
When we say that Jesus is God, we are affirming that Jesus has a divine nature as well as a human nature. Therefore, the word “God” here must refer to the divine nature, the divine essence.
Slick then asks how Catholics are using the term God in the conclusion:
In what sense is the term “God” used here? Does it mean God in the divine essence? . . . In what sense is the word “mother” used here? Does it mean that she is the mother of the divine nature?
Slick rightfully infers that “God” cannot be used to refer to the divine nature, since that would entail Mary being prior to the divine nature, which is absurd. We might even bolster Slick’s reasoning and say that mothers aren’t mothers of natures, but rather mothers of persons, and that the idea that Mary is the mother of the divine nature isn’t even what the dogma entails.
Slick is left to ask, “So, how is [God] meant?” Given the ambiguity, he concludes, “The lack of clarity is the problem.”
To strengthen Slick’s argument, it’s not merely a lack of clarity that is the problem, but the seeming switch in meaning of the term God. Given that the term can’t mean the divine nature in the conclusion, per Slick’s reasoning above (and ours), the conclusion must switch the meaning from the divine nature, as applied to Jesus in premise two, to something else, thereby committing the fallacy of equivocation.
So what might we say in response?
Well, Slick misses the mark when he thinks the term God in premise two is being used in reference to the divine nature. Maybe that’s how Christians use the term in other contexts, when speaking of Jesus’ divinity. But that’s not how it’s being used in this context, when arguing for Mary as the mother of God.
Indulge me for a moment!
Slick is right in thinking the term God can be and is used to refer to the divine nature, which just is the divine reality itself, or the divine being itself—ipsum esse subsistens (subsistent being itself), which all three persons are identical to.
Where Slick goes wrong, however, is to think that God is used solely in reference to the divine nature, or at least to think that’s how defenders of the Mother of God are using it in the above argument.
But the term God can also be used in a personal sense—that’s to say, it can be used to refer to the person to whom we offer prayers, adoration, and worship, the personal agent who brings about certain created effects, and the person who stands in a certain relation to the other persons in the Trinity. In this sense, God can be ascribed individually to the Father, the Son, or the Holy Spirit.
The reason is that all three persons are identical to the divine being. So the term God, which initially refers to the divine nature, is transferred over to refer to the persons of the Trinity to signify that they are all divine, given that they all are identical to the divine nature.
For example, Jesus says of the Father, “I am ascending to my Father and your Father, to my God and your God” (John 20:17). Thomas says of Jesus, “The Lord of me and the God of me” (John 20:28). When speaking of the Holy Spirit who gives a variety of gifts, such as knowledge, prophecy, tongues, miracles, etc. (vv. 7-11), Paul says, “It is the same God who inspires them all in everyone” (1 Cor. 12:6).
So God can be used to refer to a specific person of the Trinity without rigidly identifying the divine nature itself.
Keep in mind, however, that for some things, we must use God in reference only to the Divine Son, such as “God” suffered, “God” laughed, “God” died, and “God” was born (see Gal. 4:4). This is so because only the Divine Son took upon himself a human nature.
So, in our argument above, when we say, “Jesus is God,” God is being used specifically to refer to the Second Person of the Trinity, the Divine Son, such that the statement “Jesus is God” means “Jesus is the Divine Son.”
Consequently, in our conclusion, “Mary is the mother of God,” God is used specifically to refer to the Second Person of the Trinity, the Divine Son, such that the statement “Mary is the mother of God” means “Mary is the mother of the Divine Son.”
And since we’ve already established that it’s appropriate to ascribe the term God to the Divine Son in a personal sense, it’s appropriate to call Mary the mother of God, since she is the mother of the Divine Son, Jesus.
I think we can all learn a lesson from Slick’s challenge. First, we need to be careful to clarify the meaning of our terms when we run our argument, lest there be confusion. Secondly, we need to be careful to discern precisely how a term is being used by a community in an argument before we critique it.
Of course, these are lessons not just for arguments defending Mary, the mother of God, but also for any and all arguments. Let’s not let this opportunity to grow as apologists pass us by.