In the movies, we see Elendil in the Prologue of The Lord of the Rings: The Fellowship of the Ring holding the sword Narsil. When Elendil died at the hands of the dark lord Sauron, Narsil was broken at the feet of Sauron. When it was reforged, Elrond calls the sword Andúril. But it seems to me that these 2 swords are just the same. Why do Aragorn and Elrond call the sword Andúril rather than Narsil? Since Narsil is the original sword.
In short: Symbolism
I think Tolkien was using the forging of Andúril to amplify the symbolic effect of the Return of the King as a counter point to the rise of Sauron. There is a good bit of reincarnation and subsequent renaming throughout the trilogy, and this is one instance.
It's also worth noting that "Narsil", in Quenya, means "white and red flame", symbolizing the Sun and Moon, or "the enemies of darkness". Andúril means "Flame of the West", meant to more directly oppose the darkness to the East in Mordor.
In response to @NKCampbell's comment, I disagree (in this context). Whether or not the shards of Narsil were forge welded back together or were smelted into a new blank, Andúril is a new sword. As @Werrf says, this is a philosophical question, but it does differ slightly from Theseus's Paradox, as the same steel was used; whereas in the paradox, the ship was eventually made of entirely different material.
Very bright was that sword when it was made whole again
On that, we agree. I don't think it was smelted down. But I still say it's a new sword.
The question here is, "How much does a sword need to change to become a different sword?"
First, it went through a process. It was reforged, and, technically, the molecular structure was changed by the welding, hardening, and heat treating of the steel. Welded steel is strongest at the joints. The sword would feel different in use. It would flex differently. It would sound different on striking. This would be also be true if The Shards were treated as revert and the smelting process was performed again. Also, it was engraved almost ceremoniously. And then it was renamed. As I said, this is a significant thing in Middle-earth.
Second, it can be debated that when a
Thing breaks, it's no longer a
Thing; it's now a
- When you take a
plankand run it through a chipper, it's now
mulch. Same physical material, but not as good for making furniture.
- Is it really a TV if you can't turn it on, i.e. perform the most basic function of a TV? I call this garbage (until I fix it).
- Better still: if a plank in a table splits, and you mend it with some butterfly inlays, is it the same plank? Seems to me it's now two planks mended together...
- Another place to direct this thought experiment is to the Japanese practice of Kintsugi, in which a broken piece of pottery is mended with gold. It becomes both stronger and more valuable than the original.
Third, and perhaps most important in a literary sense, Narsil was a named weapon. Named weapons are a common trope in the Fantasy genre, and are almost characters. I'd argue that in this context, Narsil has died and reincarnated as Andúril, imbued with a new spirit. It exists for a new purpose (or rather, the same purpose but for a different person). See Gandalf the Grey => Gandalf the White.
There's an old philosophical problem called the Ship of Theseus, or Theseus's Paradox. It talks about a ship that was preserved by the people of Athens as a cultural relic; over time, they took away the planks that decayed and replaced them with new, identical planks, until every part of the ship had been replaced. The question then rose: Was it still the Ship of Theseus?
There isn't a definite answer either way; it's still a philosophical problem, and a matter for debate. The Narsil/Andúril question is similar.
While it's hard to see on the screen, the text gives us more of a notion about what was done in the reforging:
The Sword of Elendil was forged anew by Elvish smiths, and on its blade was traced a device of seven stars set between the crescent Moon and the rayed Sun, and about them was written many runes; for Aragorn son of Arathorn was going to war upon the marches of Mordor. Very bright was that sword when it was made whole again; the light of the sun shone redly in it, and the light of the moon shone cold, and its edge was hard and keen. And Aragorn gave it a new name and called it Andúril, Flame of the West.
Objects in the Rings mythos, especially those made by Elvish craftsmen, are often portrayed as having some kind of life or identity to them. When Narsil was broken, it was 'killed'; explicitly, its "light [was] extinguished". Andúril was an entirely new blade, made from the substance of Narsil, but with its own identity as the Sword Reforged.
Because Narsil was a name associated with failure
The sword broke, and at a critical point (which is what happens if you don't properly heat treat it). And then not long after, its master broke, when Isildur refused to destroy the ring.
While it was symbolically (and probably magically) important to reforge the sword for the new king, it was also important to separate it from its former name, a name with the stigma of breaking attached.