In the story “Of Aulë and Yavanna,” when Aulë’s ill-formed dwarves are graciously given “a life of their own” by Ilúvatar, Aulë asks Ilúvatar at that point to “bless [his] work and amend it.” Ilúvatar, however, does not do so, and his response accords, I think, with an actualist theology according to which what is possible depends on what is already actual, and in which “means” are more than the mere instrument to their respective “ends.”
But Ilúvatar spoke again and said: ‘Even as I gave being to the thoughts of the Ainur at the beginning of the World, so now I have taken up thy desire and given to it a place therein; but in no other other way will I amend thy handiwork, and as thou hast made it, so shall it be.
Aulë’s request, in other words, is that Ilúvatar should correct his sub-creations by effectively turning his Dwarves back into Elves or Men, the “Children of Ilúvatar,” thereby undoing his own sub-creative alterations and aberrations and restoring the original pristine plan of Ilúvatar. Remarkably, Ilúvatar declines to answer this request, and in general seems shockingly far less concerned for the dignity of his own “original” purposes than Aulë is. Far from requiring that Aulë’s “handiwork” be suppressed for the sake of his own original design, it is Ilúvatar who insists that it is his own design that must now be “altered” to accommodate Aulë’s sub-creative additions, including all their short-comings. As Ilúvatar puts it, he has “taken up [Aulë’s] desire and given to it a place” in his own, newly revised plan.
Of course, the sovereignty of Ilúvatar in The Silmarillion is such that there can’t be any real question about any of this taking Ilúvatar by surprise, or that this whole scene isn’t in some sense from the very beginning the outworking of an even greater, “master plan,” as we call it. As I was explaining to a friend recently, the fact that God sometimes has to resort to “plan B” in departure from plan A, is itself part of a more ultimate plan (call it “plan A-prime”). Yet far from this master plan involving a fatalistic achievement of a predestined end irrespective of the means, we see that the true master plan is one that achieves its end precisely in and through and therefore with its specific means, means which themselves might nevertheless involve a departure or corruption from a prior plan. Or put differently, the true master plan is one where the means themselves–of how a thing is achieved–is itself elevated virtually to the level of an end. Pragmatism is the philosophy that “the end justifies the means.” In Iluvatar we get a kind of reverse pragmatism, in which it is also the means that justifies the end, for some means are no mere instrument to a given end, but are the very meaning and exclusive possibility of certain ends.
The point that you made regarding Iluvitar’s ultimate plan being fulfilled by the means is in my opinion one of the most mysterious parts of Tolkien’s theology. I really like how you synthesize sub-creation with the sovereignty of Iluvitar in this explanation.