Prouvost on Heidegger

“If there is an ontotheological aspect of metaphysics, this is in a secondary sense [(manière)], by virtue of a concession only [(p. 97, par. 5 ff.)]. Why?  Because Thomas Aquinas rightly rejects the dimorphic interpretation of being that leads to a single ontotheological science. Theology occupies an even higher rank than ontology. It is not a part of ontotheological reflection, but its principle and end. . . .
“being qua being is the most common object of thought, which is why it is at the same time the proper subject of metaphysics and the proper object of the human intellect [(intellectus, not ratio)]. But the knowledge of God in himself goes way beyond the powers of our intellect. God is the cause of being qua being, not an instance [(partie)] of it. Because he is the principle of all things, without participating in any way in [(sans être rien de)] that which he causes (Thomas rejects the idea of a causa sui), he is the principle before all things, and we can conceive of him only relatively or negatively. The theological resolution [(resolutio secundum esse, not mere rationem; “an analysis according to the act of being,” not mere “concepts”)] leads us beyond the limits of our intellect. This is why analogy is so important for Thomas, and why our ontological reflection stops short of [(s’arrête à)] theology. The first reflection (that on being in general) stops short of the point at which [(s’arrête là où)] the second (that on God as the principle of being) begins. In this sense, Heidegger was right in his analysis of the Prologue to the commentary on the Metaphysics: metaphysics is not a single science. The rational analysis of terms is not the return to the intelligible principle. But it is also why Heidegger was wrong in his general definition of ontotheology, for this [(cela)] shows precisely that metaphysics is not an ontotheology.
“Thus, the birth of metaphysics is not the equivalent of the discovery of a first mover. The latter can be attained by another rational science, in a physical reflection. Metaphysics begins with the consideration of the abstract entity, [an entity] in matter, but capable of being separated from it; and it stops short of the point at which separated, divine esse begins, because this esse is the cause and the principle of everything that it is capable of reflecting upon. God remains outside of metaphysics.
“This is why metaphysics cannot allow for an ontological proof. An ontological proof implies that the esse (the existence) of God is arrived at via his ratio (his concept). But God is not included in our ratio of being [(l’étant)]; he is its principle.  The contemplation of the principle as such does not belong to metaphysics.
"There cannot be a Platonic synthesis.  There are [only] two different sciences, which must not be confounded, even if the second continues the first."

Géry Prouvost, “Quand commence l’ontothéologie? Aristote, Thomas d’Aquin et Duns Scot,” Revue thomiste 95 (1995): 99-101 (85-108).  The (Neo-)Platonic or Avicennian synthesis ignores the Christian distinction, "the [radical] difference between mathematical abstraction and absolute divine separation", "l'étant séparé" and "la divinité séparée", creation (however purely intelligible) and Creator.