Others have speculated on who – and what – he is: one of the Mala … a Maiar … perhaps even Eru Illuvatar. One blogger, the Ranger of the North, speculated he is the spirit of the Music of the Ainar, by which the world was created.
That's a most intriguing thought. Take it one step further. JRR Tolkien in one of his letters once described Tom Bombadil as “the spirit of the vanishing landscapes of Oxfordshire and Berkshire.” In the same letter, he described Goldberry – Tom's lady – as the seasonal changes in nature.
Perhaps Tom is the spirit – or perhaps more accurately – the embodiment, of Middle Earth itself: Middle Earth as it has existed from the beginnings to the Third Age – the age imperiled by the Dark Lord Sauron. Tom says he remembered the first raindrop and the first acorn, and – significantly – he knew the dark under the stars when it was fearless … before the Dark Lord came from Outside. The Elves' name for him translates to “Oldest and Fatherless.” Gandalf says he is “the eldest being in existence.”
The One Ring has no effect on him. He takes little note of it, and at the Council of Elrond, Gandalf expresses concern that, if entrusted with it, Tom would not understand its importance and in fact would lose it. Yet one of the Elves, Galdor, suggests that Tom would be unable to withstand a siege by Sauron “unless such power is in the earth itself.” Indeed, there is the suggestion that Bombadil would not survive if the Dark Lord comes into power.
That, to me, holds the key. Tom Bombadil can only survive if Frodo, Gandalf, Aragorn and their allies can succeed in destroying the One Ring, thereby defeating Sauron. The same is true for Middle Earth.
The world itself will be forever changed, destroyed, if Sauron comes to power.
It's an intriguing idea. At least … I find it so.
It's all speculation, of course. We can have no certain answer to Tom Bombadil's identity, and … It would seem that Tolkien intended it that way. He himself said there are some things that should remain mysterious in any narrative.
So Tom Bombadil remains – as Winston Churchill once said of Russia – “a riddle wrapped in a mystery, inside an enigma.”
May he ever be so.