Tolkien’s metaphysics of evil, part 14
The first point of comparison I want to make between Tolkien’s and St. Thomas’s respective doctrines of evil, one that will furnish us with the organizing principle for much of the analysis to follow, has to do with the hierarchical nature of reality as a whole, a point that St. Thomas himself raises toward the beginning of his discussion of evil in the Summa. For St. Thomas the hierarchical structure of creation is necessitated by the fact that God’s only “motive” (so to speak) in creating is to communicate his own goodness, meaning that the created order, if it is at all to emulate adequately God’s goodness towards creation, must itself consist in a hierarchy of diverse and unequal beings. Only in this way can the divine drama of a higher reality ministering to and bringing to perfection a lower order of being be carried out on a finite scale. It is much this same drama that Tolkien illustrates through the Valar Aulë who, impatient with the relative emptiness and lack of diversity and inequality at that point in the world, attempts to make the Dwarves, and who justifies his action by saying that he merely desired beings upon whom he could exercise something of Ilúvatar’s own fatherly care. As I have also suggested recently, one way of viewing Tolkien’s invented races, the Elves and the Valar in particular, is to appreciate them as refinements upon or further iterations within an otherwise Thomistic hierarchy of being. Because the perfection of the universe requires that there should be, as Thomas puts it, “inequality in things, so that every grade of goodness may be realized,” and because one “grade of goodness” consists in things that can nevertheless fail to achieve the level of goodness intended for it, it follows for St. Thomas that the perfection of the universe “requires that there should be some which can fail in goodness, and thence it follows that sometimes they do fail” (ST 1.48. 2). As Thomas goes on to conclude, it is in this failure of a thing to achieve its goodness that evil consists.
 “[I]ta perfectio universi requirit ut sint quaedam quae a bonitate deficere possint; ad quod sequitur ea interdum deficere.”