Who calls you hobbits, though?

"Hoom, hmm! Come, now! Not so hasty! You call yourselves hobbits? But you should not go telling just anybody. You'll be letting out your own right names, if you're not careful."

"We aren't careful about that," said Merry, "As a matter of fact I'm a Brandybuck, Meriadoc Brandybuck, though most people call me just Merry."

"And I'm a Took, Peregrin Took, but I'm generally called Pippin, or even Pip."

"Hm, but you are hasty folk, I see [...] I'll call you Merry and Pippin, if you please --- nice names. For I am not going to tell you my name, not yet at any rate." A queer half-knowing, half-humorous look came with a green flicker into his eyes. ...

Being a lazy reader (and I really ought to be trying to work out when and why there's a splitting in some queer long-exact sequence involving spheres... the answer is "in exactly those cases I want to ignore") it has taken me a long while to think about the flurry of names-as-such in the Epic; some of this is due to the rich linguistic history that Tolkien imagined for his subcreation. But I'm starting to piece together something more: even deeper than Tolkien's love of euphony (whether or not Greek!) there seems to be something of a philosophy of names for things that he is keen on approaching from several angles.

"Eh? What's that? Don't you know my name yet? That's the only answer. Tell me, who are you, alone, yourself and nameless? But you are young, and I am old. Eldest, that's what I am."

It is curious that Bombadil claims this title for himself, and Elrond seems to ackowledge it; while Gandalf and Celeborn seem to propose him we know as Treebeard, who opened the topic for us, as "Eldest", and "the oldest of all living things". Perhaps this grant should be informed by our knowing (from the Silmarillion) that Gandalf is actually akin to Saruman and Sauron and the Valar, who have their memory from before the making of Eä or Arda in it, or the shaping of Middle Earth within that. Whether Bombadil or Treebeard is of the same sort or something else I can't tell or guess: the histories are confused, or I am.

But even more: Bombadil echoes something of Treebeard's philosophy in asserting that, on the one hand it is difficult (if not impossible) to talk of specific people without having some word to use as naming them, yet there is often something in each person's Story that will pin down which person they are: and so, Eldest works for Bombadil. If you aren't likely to meet Bombadil (and most of us aren't), then Eldest may as well suit Treebeard --- not that you're much more likely to meet him than Old Tom.

"Mithrandir we called him in elf-fashion," said Faramir, "and he was content. Many are my names in many countries he said. Mithrandir among the Elves, Tharkûn to the Dwarves; Olórin I was in my youth in the West that is forgotten, in the South Incánus, in the North Gandalf; to the East I go not."

To the East... there are hints that in the Lost Tales more is made of the "Rods of the Five Wizards" --- you'll note we only ever have names and colours for three! --- that two Blue Wizards got lost in the East; but here we learn that to some extent, names are things given us by those around us. In this sense none of my noms de dactylographe is really apt, least of all that I use most. Mind you, wherever I go on the internet, if the local service doesn't assign me a name, whatever name I do use is effectively one I'm claiming for myself.

About that, let's jump volumes:

But when Gwindor would tell his name, Túrin checked him, saying "I am Agarwaen the son of Úmarth," --- (which is "Blood-stained, the son of Ill-fate") --- "a hunter in the woods"; and the Elves of Nargothrond questioned him no more.
[...]

On the one hand, it may be perilous to play with names too recklessly. There are plenty of cautions out there against nicknaming your Guardian Angel, for instance --- it being sufficient to use the title "My Guardian dear", and difficult to be sure that some other word doesn't address something less holy, or less wholesome. Very perilous; though Tolkien is not univocal on Man's proper relation to Peril: "Indeed, [Gimli], you are beset with dangers, for you are dangerous yourself, in your own way" on the one hand, while on the other "Yet I am wise enough to know that there are some perils from which a man must flee." But let us see also what Gwindor later advises his dangerous friend:

Now when Túrin learned from Finduilas of what had passed, he was wrathful, and said to Gwindor: "In love I hold you for rescue and safe-keeping. But now you have done ill to me, friend, to betray my right name, and call my doom upon me, from which I would lie hid."

But Gwindor answered: "The doom lies in yourself, not in your name."

That is, there is a definite sense in which what I call myself (short of impersonation -- cf. Amlach from "The coming of Men into the West", Silmarilion) is less important than my character in deeds and in conversation, and certainly the one is easier to change than the other. Túrin is indeed seen to be a tragic figure in the old Greek sense --- for though the "weight of [Morgoth's] thought" (Narn i chin Húrin) oppresses him, yet it is by his own habits that destruction and despoliation is able to follow wherever he goes, and eventually overcome him with despair.

On the other hand, there is --- even beyond history, the things we've done --- a sense in which certain names are more apt, though they may have to wait some time come into their own:

And so the very name it was foretold at his birth that he should bear was chosen for him by his own people.