My coming to grips with Priest's identities

Priest says, "The identity of an object is not determined by its properties at any one world" (90). This is all well and fine, but then what is identity for Priest? These were my humble thoughts. Perhaps they reflected a concern similar to the "What the Hell?" objection, where Priest has to hold that identities are sui generis entities, unlike other things we have seen.

My worry with Priest's theory of identies reached its apex on page 121, where he writes, "Suppose that you and I decide to write a story about Holmes(Doyle's character). But our stories, whilst presupposing all that Doyle said, are incompatible. In my story, Holmes has a maiden aunt; in yours, not. Then in the worlds that realize the way that I have represented Holmes, he has a maiden aunt. In the worlds that realize the way that you have represented him, he does not. Different worlds, but still the same Holmes."
This, I thought, led into dangerous territory. Suppose that we said contradictory things about Holmes himself, not something superficial like the fictional existence of an aunt, or even the location of a wound, but something that is essential to Holmes.
-if your story denied an essential part of Holmes, and mine accepted it, SURELY we could not be talking about the same Holmes.

This, I thought, was a huge mistake on Priest's behalf (unless identities, like the mythical direction of a toilet flush, somehow functioned differenlty in the Southern Hemisphere).

But then I asked myself - "what is essential to Holmes?" His detectivehood, perhaps? But this cannot be, for surely there are possible worlds where Holmes has a successful career as a chimneysweep, and would still be Holmes.

In my search for another example, I turned to the chimera mentioned in Chapter 3. Let us suppose that a chimera is only such that it has the essence of a lion, the essence of a goat, and the essence of a serpent (this is the second way a chimera can be taken, see p.71). Now there is no doubt as to what is essential in a chimera as a whole. So if a class is given an assignment to write about a particular chimera (call it Nadirub), I, in my fictional story, describe Nadirub as above. My classmate does not; she tries to describe Nadirub as lacking the essence of a goat. However, she cannot do this - There is no way she could imagine a chimera without it having the essence of a goat.

In the same way we will find that if we, in a story, denied that Holmes possessed something essential to him we would, we could, NOT be talking about Holmes.

So I came to see that Priest, and the noneist account may be right; identity is far removed indeed from its properties at any given world.