A theology of the possible, part 6
James Ross’s denial of the existence of a universal domain of possibles leads him to redefine what we mean by divine omnipotence, a redefinition that I want to argue makes for a much tighter and meaningful analogy between the creative power of God and the sub-creative power of man. For Ross, “omnipotence is FORMALLY not the power to make states of affairs obtain or to actualize the possible. It is the power to cause being ex nihilo” (emphasis original). The conclusion of this redefinition for Ross is that
God’s power is more awesome. Its domain is realized with its exercise. What is possible ad extra is a result of what God does. God’s power has no exemplar objects, only a perimeter (that is, finite being) plus a limit (that of internal consistency, compatibility with the divine being). God creates the kinds, the natures of things, along with things. And he settles what-might-have-been insofar as it is a consequence of what exists… In sum, God creates the possibility, impossibility, and counter-factuality that has content (real situations) involving being other than God. (318-19)
For Tolkien I think there is a related sense in which the “domain” of the human sub-creator’s activity is not some pre-existing, speculatively discoverable given, but is rather determined and “realized with its exercise.” As self-identified “hill-billy Thomist” Flannery O’Connor, under the influence of Jacques Maritain’s work on Art and Scholasticism, advised one of her acquaintances about the sub-creative process, “Strangle that word dreams. You don’t dream up a form and put the truth in it. The truth creates its own form. Form is necessity in the work of art.” (Replace “the truth” with “God” in the preceding quote and you have almost exactly what I take to be Ross’s antithesis between theological exemplarism and his variety of divine voluntarism.) The artistic possibilities open to the sub-creator, in other words, are less a matter of isolated, abstracted “logical compatibilities” of the imagined forms themselves (O’Connor’s “dreams,” as it were), as they are a matter of the inchoate potentialities of his images to suggest, coalesce, and so produce a coherent “secondary world,” one possessing the “inner consistency of reality,” and in which those forms might then live and move and have their being. In his essay “On Fairy-Stories” Tolkien gives the example of a “green sun,” which he says is relatively easy to picture mentally, but suggests that its sub-creative propriety lies elsewhere, namely in the sub-creator’s ability to fashion a world in which such strange and unfamiliar structures may nonetheless be seen to fit. In Tolkien’s poetics, the faculty of Imagination includes not only the “mental power of image-making” (and in fantasy or fairy-story, of making images especially marked by an element of “strangeness” or “unreality”), but beyond that, the ability to “perceive,” “grasp,” and “control” the “implications” of the image. To this power of Imagination he adds a further faculty responsible for the “achievement of the expression [of the image], which gives (or seems to give) ‘the inner consistency of reality,’” a faculty that Tolkien calls “Art, the operative link between Imagination and the final result, Sub-creation.” For the human sub-creator as for Ross’s divine creator, what is possible for the maker is the result of what the maker does.
 O’Connor, The Habit of Being, 218.
 We might characterize this as Tolkien’s way of admitting something that Ross argues elsewhere, namely that “imaginability does not imply (in this case, sub-creative) possibility.” See Ross, Thought and World.