Signifying Equality with Movement

I came across something helpful in Aquinas (ST Iª q. 42 a. 1 ad 3). Check it out: Should we call the persons of the Trinity equal? Well of course we should.

But one of the objections he considers (obj 3) is that a relation of equality is reciprocal. But to say the Father is equal to the Son sounds weird and backwards; it might be as wrong as saying the Father is the image of the Son (which he’s not).

So Aquinas makes a distinction: “Equality & likeness in God may be designated in two ways–namely, by nouns and by verbs.” Huh. (It’s nomina et verba in Latin.)

If you use nouns, like essence or greatness I guess, then equality is mutual and reversible, “because the divine essence is not more the Father’s than the Son’s.” It makes sense to say the Father has the Son’s greatness, which is just the flip side of the Son having the Father’s greatness. It’s identically the same greatness. But that’s when we’re talking with nouns, which have a wonderfully static character.

But verbs: They “signify equality with movement” (verba significant aequalitatem cum motu). The Son receives from the Father that he is equal, but the Father does not receive from the Son. So “the Son is equalled to the Father, but not conversely.”

This is interesting and helpful for several reasons. It states the full equality of Father and Son without flattening out their relation to each other and thinking of them as interchangeable, or their relation as reversible.

Without using the word homoousios (consubstantial), Aquinas captures the taxis that was built into that word in much pro-Nicene usage: That is, it’s more proper to say the Son is homoousios with the Father than that the Father is homoousios with the Son, or that they are are homoousios w/each other.

[This was a Twitter thread that I posted in May 2020; I decided I wanted it here for more permanence, but I didn’t clean it up much.]

[A Spanish translation of this post is available at Credo.cl]