In his book on Bonaventure (Great Medieval Thinkers) , Christopher Cullen argues that Bonaventure does not separate the treatise de deo uno from one de deo trino .  Cullen’s explanation would not, I suspect, satisfy Rahner, since he distinguishes two approaches, one which “fixes the soul’s gaze primarily and principally on Being Itself” leading to the “first name of God,” namely “He Who is” from a second approach in which the soul gazes “on the Good Itself, saying that this is the very name of God.”  That sounds very close to the double approach that Rahner condemns.

Still, Bonaventure’s intention is certainly not to separate being and good, and he combines the two approaches with a Levitical image: “Having considered the essential attributes of God, we must raise the eyes of our intelligence to the contuition of the Most Blessed Trinity, so as to place the second cherub facing the first .  Now just as Being itself is the principal source of the vision of the essential attributes of God, as well as the name through which the others become known, so the Good itself is the principal foundation of the contemplation of the personal emanations” (emphasis added).

Treatises de deo uno and de deo trino are thus inseparable, complementary views of the glory that is enthroned above the cherubim.