As mentioned in the previous post, in Marion’s more recent work, St. Thomas escapes all three characteristics of onto-theo-logy. Regarding the first characteristic, viz., inscribing God within the domain of metaphysics, Thomas is “acquitted” because for him (unlike Scotus and Suarez) esse commune (common or created being) is the proper object of metaphysics. Hence, God only factors into the consideration of metaphysics in an indirect way, viz., as the causal principle (Creator) of common/created being. For Aquinas in contradistinction from the thinkers mentioned above, God and creatures are not conceived under a common univocal concept of being.
Regarding the second characteristic, viz., that the “God” establish a causal foundation of all the common entities (which turns out to be a reciprocal founding of sorts), Thomas is likewise “not guilty” because of the distinction he makes between esse commune and esse divinum. Esse as used in these two designations is not understood univocally (either metaphysically or predicatively), but analogically. That is, the “esse” in esse commune is received from God and is common to all created beings—beings that are esse/essence composites. In contrast, the “esse” of esse divinum has only one referent, viz., God who is the “act of being” and whose esse is identical to his essence. Thomas, then, given this distinction, upholds God’s transcendence. Though it is the case that Aquinas’ doctrine of analogy names God as the efficient cause of common being, he escapes the second characteristic of Heidegger’s critique because his understanding of causality in creation is asymmetrical. In other words, God (the “ground” of esse commune) does not stand in a reciprocal relation to his creation. Rather, the dependency is “one-way”—creation is wholly dependent upon God for its being and intelligibility, but God is in no way dependent on creation for either.
Regarding the third characteristic, Marion highlights two arguments of St. Thomas’ against the idea of God as causa sui. The first appeals to a logical contradiction that such a claim would involve. That is, given that nothing can cause itself, God cannot cause himself because God would have to exist prior to and in some way distinct from himself (p. 56). Secondly, (and Marion thinks that this argument is more significant), in order to maintain his transcendence as efficient cause (in the redefined Thomistic sense), God must “withdraw Himself from causality.” In other words, God exercises causality toward beings but he himself is not part of this causality—a causality extended only to created beings whose existence and essence are distinct and composite. Created, composite beings receive their esse from God whose esse and essence are identical. Stated in a slightly different manner (and basically the argument of the De ente), given that all created beings are esse/essence composites, there must be a first whose esse is his essence and hence whose esse is both wholly other from created esse and the principle (Creator) of created esse, lest we have an infinite regress. In this schema, causality only applies to created beings and clearly does not apply to God [pp. 56-57].
Marion ends the article by suggesting that even though Aquinas privileges being (ipsum esse) instead of the Good (as in the Dionysian tradition), there is still a way in which this may be interpreted such that Aquinas is exonerated from the onto-theo-logy charge. At this point many Thomists have concluded that Marion seems to suggest that we read Aquinas as promoting a radical apophaticism—God is esse in name only. In other words, because God’s esse is so wholly other than created being, it can be revealed or known only as unknown. As Marion explains, “this pure esse reveals itself in principle as unknowable as the God it names. God known as unknown—this implies that his esse remains knowable only as unknowable, in sharp contrast to the esse that metaphysics has essentially set in a concept to make it as knowable as possible” (p. 63). A few lines later, Marion writes, “[Thomas] does not think God in a univocal way according to the horizon of being. Or simply: the esse that Thomas Aquinas recognizes for God does not open any metaphysical horizon, does not belong to any onto-theo-logy, and remains such a distant analogy with what we once conceived through the concept of being, that God proves not to take any part in it, or to belong to it, or even—as paradoxical as it may seem—to be. Esse refers to God only insofar as God may appear as without being—not only without being as onto-theology constitutes it in metaphysics but also well out of the horizon of being, even as it is as such (Heidegger)” (p. 64). Such an interpretation would suggest that given the radical transcendence and incomprehensibility of God’s esse, Thomas’ naming of God ipsum esse should be taken as a negative name without any conceptual content; hence, Thomas’ understanding of the divine names, as well as his doctrine of analogy should be understood in a radically apophatic way. However, others have argued that on Marion’s read Thomas’ doctrine of analogy, as well as the divine names, function phenomenologically and indeed reveal something truly (yet not exhaustively) about God. In other words, following Denys, the divine names are a kind of “iconic speech” that unfolds and discloses God to us in the context of the liturgy. Here (idolatrous) predication of God in the sense of defining God is ruled out and in its place a new discourse springs forth—the discourse of praise as the proper response to Him who makes Himself known as Goodness, as Love, as Gift.
 See e.g., Morrow, Derek J. “Aquinas, Marion, Analogy, and Esse: A Phenomenology of the Divine Names?” International Philosophical Quarterly, Vol. 46, no. 1 (March 2006): 25-42.