: He seemed to fear its destruction when Frodo claimed it for himself at the cracks of doom. But perhaps he wasn't really afraid for himself, he just didn't want to lose the ring. That doesn't seem very plausible to me, but maybe it makes sense.

: In any case, the case you're stating seems to be what pretty much everybody here believes but me, namely that Sauron would not have thought that destroying the ring would have destroyed him as well. That just really surprises me, for reasons I've given in plenty of posts below.
: If I'm all alone in this, I will consider changing my view, even if I don't hear any compelling evidence. But I still think this is an implausible situation -- that Sauron wouldn't know much more about his own ring than this gives him credit for.

Frodo and Sam are on Mount Doom, closer to Sauron than ever before. Yet, Sauron does not perceive the presence of the ring untill Frodo claims the ring as his own. This can be explained by Sauron being focused on Aragorn's army, but why would he be focused on such a small army that his forces could easily crush. The only answer that makes sense is that Sauron believed that Aragorn possessed the Ring, and intended to use it against him.
Fear that someone would use the ring against him, appears to be the over-riding concern of Sauron, not the ring's destruction.
This leads me to believe that Sauron did not believe destruction of the ring would harm him.

: : I don't believe that Gandalf, or any of the wise, realized that destroying the ring would also destroy Sauron. Their intent from the onset was to destroy the ring in order to prevent Sauron from regaining and using it.

: But see, here's one problem: Gandalf says on many occasions that destroying the ring would destroy Sauron. I've listed some of the passages in other posts. One is in "The Last Debate" (which led to the dispute on whether Gandalf would lie or not).
: You're right that it doesn't make much sense to suppose that Gandalf would know this about the ring when Sauron doesn't! Yet Gandalf does seem to know it. And he claims that Sauron doesn't.
: That's why I said it was a whopper. I think Gandalf just misspoke.

In the early instances, just what did Gandalf mean by "destroy Sauron"? Did he mean kill Sauron outright, or did he mean something entirely different. Perhaps he ment that destruction of the ring would ruin, or weaken, Sauron to the point where he would no longer pose a threat.

The Last Debate, my pep talk comment aside, is something entirely different. At this time, Gandalf had come back as "the White". We do not know what knowledge was imparted to him prior to his return. It is entirely possible that Gandalf did in fact know what would happen when the ring was destroyed.

: snip