[The Squatter of Amon Rûdh]

Let's not forget in all of this that presumably the letter to Milton Waldman concerns the Silmarillion, whereas his statements about "a fundamentally Catholic work" refer to LR. I don't know which of the letters we're talking about here, since my copy of the Sil doesn't include it, but surely just because Tolkien thought that LR was strongly influenced by Catholicism doesn't mean that the Silmarillion (which was never completed) must necessarily admit the same interpretation.

I think that the comments above about not wanting to be pigeonholed and not wanting to push readers into particular beliefs are spot on. Something can be 'fundamentally Catholic' without transmitting a fundamentally Catholic message; the Catholicism might be buried deep in the foundations, underpinning the work's moral structure but not intended to guide the reader in any particular direction, without intending to deliver a fundamentally Catholic message.

When it comes to allegory it's worth considering what an allegory is: the portrayal of one thing in the guise of another. Where an allegory is clearly intended, such as in Tolkien's tower analogy or, for example, Animal Farm, there is always a direct and consistent correlation between the real world and the allegorical portrayal. Tolkien wanted to scotch the idea that LR contains any such thing and it doesn't. No allegorical interpretation can be applied consistently to the narrative, just as no one message can be derived from it. When Tolkien spoke of applicability he meant just that: people might apply events in the book to real life and thereby inform their decisions. The two work in entirely opposing directions: with allegory the events come first and the writer comments on them; with applicability, the writing comes first and then is applied to the events as they occur. The fact that anyone can find almost any message in LR is a result of the supreme applicability of its themes, particularly those relating to conduct and morality. The danger arises when someone thinks that because a theme seems so strong and so right it must be the overall point of the work. In every case I've seen it isn't, and that's what Tolkien meant.

Whilst you might see this in LR, the Silmarillion is much more complicated and heterogeneous a work, and any statements about its influences would have to take account of the whole span of its development and each influence at each stage thereof. The idea that it has any consistent theme other than the struggles of the Noldor and Edain seems to be reaching too far. Perhaps that is what Tolkien intended, but then again the letter in question may have been one of those in which Tolkein talks about LR, in which case the Sil is not pertinent. The fact that Tolkien intended to publish both works together should not be taken as a statement that the two expound upon common themes: for Tolkien, the Silmarillion forms a backdrop to LR, and the two are more valuable when taken together, but they are not parts of the same work.

What I suppose I mean is that Tolkien could, entirely truthfully, claim one influence or intention for one part of his work whilst still denying it for another. Again he was not immune to the human trait of wanting to please his correspondants, so of course he would play up its religious aspects to the religious or its philological aspects to academics. That means neither that any one statement of his can be taken to define an entire work nor that none of his statements can be trusted. The danger is that someone will latch on to one thing that Tolkien said and think that it is some sort of magic key for unlocking the Middle-earth Code. We all want to think that we are privy to something that only we and the author understand, but usually either everyone else knows about it too or it turns out to exist only in one person's head. A classic example of this was the member of another forum who claimed to have found the Entwives, and made several cryptic statements about it, statements so cryptic as to be meaningless. Nobody has found the Entwives and nobody will find them, because Tolkien hadn't hidden them. Now, he may contradict himself about that subject, as he often does about a number of things, but people contradict themselves all the time and I have no doubt that he always believed what he was saying when he said it. When two statements from Tolkien disagree, I tend to start by seeing which of them fits most closely with observable trends in his wider body of work. After that you get into the murk of canonicity discussion, which has always bored me rigid. I'm not a great fan of angels on pin-heads.

I've rambled across a lot of ground here, but hopefully I've managed to pull this into some semblance of order. I suppose my point is that Tolkien didn't lie to his correspondants: he just didn't expect his letters to enter the public domain, and so made unguarded statements in them that he wouldn't have made in a preface. We need to be careful with them, but we shouldn't cease to trust them. In many cases they both turn out to be true in a way, and we just need to apply a little subtlety in our understanding of them.