The theme of faith and reason makes perhaps its most express appearance in Tolkien’s fiction in the Athrabeth Finrod ah Andreth (“The Debate of Finrod and Andreth”), a dialogue Tolkien wrote after the publication of The Lord of the Rings, addressing many of the philosophical and theological principles underlying his mythology. According to his son Christopher, the dialogue held some “authority” for his father as to how his mythical history as a whole was to be interpreted, and Tolkien’s (unfulfilled) wish was that it should be published as an appendix to The Silmarillion (Morgoth’s Ring 303 and 328-9). A record of an exchange between the Elf-lord Finrod and a mortal woman named Andreth, the Athrabeth represents one of the earliest conversations in the history of Middle-earth between two representatives of their respective races, in which the two participants attempt “to fathom the relations of Elves and Men, and the part they were designed to play in… the Oinekarmë Eruo (The One’s perpetual production), which might be rendered by ‘God’s management of the Drama’” (329). In a separate commentary he wrote on the dialogue, Tolkien spells out at even greater length many of the Elvish “basic beliefs” presupposed by Finrod in the course of his conversation with Andreth, beliefs which the Elves had acquired from their “created nature; angelic instruction; thought; and experience” (330). Of particular relevance here is the reference to “angelic instruction,” which indicates that part of the foundation of Elvish knowledge consisted in truths known neither intuitively, discursively, nor experientially, but simply on authority, specifically, the authority of a higher, spiritual being. Thus, despite the absence of any formally recognized divine revelation in Tolkien’s mythical history, this portrayal of the Elves as existing in a relationship of trusting subordination to the angelic Valar resembles the New Testament’s characterization of the Old Testament as a time when God’s people were under the tutelage of angelic administration and revelation, but which was afterward surpassed by God’s direct revelation through his Son (Acts 7:53, Gal. 3:19, Heb. 2:2-3). As I may address in a later post, it is a similar logic and progression of history which the Athrabeth anticipates as well.
Of the aforementioned sources of Elvish basic beliefs, possibly of even greater import than “angelic instruction” is Tolkien’s reference to the Elvish “created nature,” which he implicitly distinguishes from both Elvish “thought” and “experience.” What exactly he means by “created nature” is not made clear in his commentary, but in the Athrabeth itself Finrod credits the Elvish nature as the source of their faith or estel, which he defines as “trust,” a condition that is “not defeated by the ways of the world, for it does not come from experience, but from our nature and first being” (320, emphasis added). This is interesting as it implies that, for the Elves at least, the exercise of faith or trust is not “supernatural” in the sense of it being something adventitious or superfluous to the Elvish nature, but instead emerges from, is rooted in, and is thus necessary for the completion or perfection of the Elvish “nature and first being.” And while Tolkien here emphasizes the naturalness of faith as far as its origins in the individual are concerned, the orientation of this faith has an unmistakably supernatural dimension, as may be seen when Finrod, in his response to Andreth’s despair in thinking that the Creator has abandoned Men and the world, identifies as the “last foundation” of this faith the fact that Elves and Men are indeed the “Children of the One” and that the fatherly Eru will therefore “not suffer Himself to be deprived of His own, not by any Enemy, not even by ourselves” (320). In this way Tolkien may be seen to challenge an overly facile and modern division between the natural and the supernatural, inasmuch as hope and trust in God and his ability to intervene supernaturally in human (or Elvish) history is something eminently natural and not merely extraneous to us as “children” of God.
 Christopher Tolkien places the Athrabeth’s composition sometime in 1959 (MR 304).