Augustine's 3 Rules When Speaking of God

Augustine's Grammar of Theology from Book 5 of De Trinitate

Augustine's 3 Rules for Fitting Language of God

In the fifth book of his De Trinitate, Augustine shifts his theological focus to what transcends human comprehension. As he says: "From now on I begin to speak of subjects, which are altogether above the power of any man" (Aug., De Trin. 5.1.1).

What follows in Book 5 then is Augustine's attempt to develop a theological grammar adequate for discussing both the divine nature and the relation of the Father, Son, and Spirit. He discovers three rules that should rule our speech about God.

Rule 1: We can’t judge uncreated nature by created things

Augustine's first rule challenges the direct application of earthly categories to divine realities. He asserts: "whatever is said about a nature invisible, unchangeable, with the highest kind of life and sufficient to itself, ought not to be judged by the ordinary standard of visible, changeable, mortal, or dependent things." (Aug., De Trin. 5.1.2)

This rule guards against anthropomorphic or materialistic conceptions of divinity. In other words, created things cannot be univocally applied to the uncreated Creator.

Rule 2: We mustn't confuse substantial and relational words

Augustine's theological grammar secondly distinguishes between substantial and relational predication:

"Wherefore, let us hold fast above all to this principle: whatever in that divine and exalted sublimity is said in reference to Himself is said according to the substance; but what is said in reference to something does not refer to a substance but to a relationship. The power of the same substance in the Father, the Son, and the Holy Spirit is so great that everything which is said of the individual person in reference to Himself may also be said of them together, not in the plural, but in the singular number." (Aug., De Trin. 5.8.9)

Attributes predicated of God substantially (e.g., goodness, wisdom, power) apply equally and identically to Father, Son, and spirit. Relational terms (e.g., Father, Son, begotten, begetter) distinguish the persons without introducing substantial division within the Godhead.

Augustine thus affirms that "God is great" and that "Father and Son is/are God" without logical inconsistency because the first word “great” refers substantially to God while the names Father and Son are relational terms. They do not refer to substance but only to relations, namely, of fatherness and sonness.

Rule 3: What is said of One is said of the Others

Augustine's third rule sums up the previous distinctions:

"To sum up: whatever is spoken of God in respect to Himself and of each single person, that is, of the Father, the Son, and the Holy Spirit, and together of the Trinity itself, is to be predicated in the singular of each divine person and not in the plural" (Aug., De Trin. 5.8.9)

God is great, good, and love. And so Father, Son, and Spirit are great, good, and love. What is said of God in non-relational ways is said of God substantially. The Father is not the Son, and the Son is not the Father, but the Father and Son are one goodness.

Conclusion

Augustine's rules for theological discourse in Book 5 of De Trinitate give us a grammar to speak of the mystery of God. They protect us from heresy, draw our minds to the meaning of Scripture, and allow us to know God with clear concepts.