"Tales out of the South", Gollum went on again, "about the tall Men with the shining eyes, and their houses like hills of stone, and the silver crown of their King and his White Tree: wonderful tales. They built very tall towers, and one they raised was silver-white, and in it there was a stone like the Moon, and round it were great white walls. O yes, there were many tales about the Tower of the Moon."I have emphasised the co-referring expressions. There are actually two sets. The first begins with an indefinite noun phrase 'one', and continues with the terms 'it', 'it', 'the Tower of the Moon' as uttered by Gollum, the relative pronoun 'that' uttered by Frodo, and 'the Tower of the Moon' as uttered by Frodo at the end. The reason for the co-reference is entirely due to rules of use for singular terms. Even if Tolkien had intended to refer to different things, he would have failed, because of rules like these. His intention is realised only by the instruments - the signs - he is using, which give a fixed and determinate reference. The other set has one member in this passage: 'Minas Ithil'. This set was begun much earlier in the book, and each member has likewise a determinate reference back to the previous ones. Tolkien joins them at the point where Frodo says "That would be Minas Ithil". Now we know (as long as we know the identity statement uttered at this point) that the two chains are co-referring. But this identity is not a grammatical rule or some other 'rule of narrative', but is contingent upon a statement made within the narrative - the identity statement "A (that tower) = B (Minas Ithil)".
"That would be Minas Ithil that Isildur the son of Elendil built," said Frodo. "It was Isildur who cut off the finger of the Enemy."
"Yes, He has only four on the Black Hand, but they are enough," said Gollum shuddering. "And He hated Isildur's city."
"What does he not hate?" said Frodo. "But what has the Tower of the Moon to do with us?"
The possibility of there being separate 'referential chains' within a narrative which are identified as co-referring at some later point provides a device that writers have used for dramatic purposes. In Dumas' The Vicomte de Bragellone, we are introduced to a traveller at a hostelry in Blois, 'a man of scarcely 30 years, handsome, tall, austere, or rather melancholy, in all his gestures and looks'. In the story that follows, this person is referred to as 'the gentleman', 'the traveller' and, intriguingly, as 'the unknown'. Intriguingly, because the expression 'the unknown' identifies the stranger perfectly well within the story, where he is actually 'known' or identifiable, but not outside the story, even though the expression signals that he is known or identifiable under another name or description. Later we learn that he is Charles II, King of England.
Sometimes, as with 'The Two Towers', an author may fail to disclose a fictional identity. In this case, we can ask what he may have intended to refer to. The point is that reference is always fixed and determinate, and depends on meaning and convention. Intended reference is not.