Through thick and thin

Bill Vallicella republishes a post on the nature of existence from 2008.   I have been following Bill's discussion with Ed Ockham since before then I think.  It's never been clear quite where their disagreement lies, though with this post we may be getting closer to the nub of it.   One of Bill's perennial contentions is that the attempt by Quineans such as Peter Van Inwagen to puncture and deflate a  'thick' theory of existence by trivially translating existential statements into the predicate calculus is a failure.  He says, for example, that the translation of the singular existential assertion
Max (the cat) exists =df (∃x)(x = Max)
fails to define existence because the objects of the domain of quantification implicit in the right hand side are presumed to be existents. I sympathise with Bill here, though I think he's knocking down a straw man. My own view is that such singular existentials are not indicatives at all and hence are untranslatable into predicate calculus. But Bill also maintains that the general existential explication
Cats exist =df (∃x)(x is a cat)
fails for the same reason.  I don't agree.  I have no problem with translating out 'exist' used generally.  For if we drop the predicate calculus formalities we are saying
Cats exist =df something is a cat.
Bill demurs, insisting that we should render this as
Cats exist =df something that exists is a cat,
and then we are no further forward as 'exists' appears on both sides.  So the issue is, Is there a distinction between something is a cat and something that exists is a cat?  Ed and I both say No, there is not.  An immediate objection to Bill's view is that if we have a meaningful distinction here then it would appear that a sentence like
Something that does not exist is a cat
is meaningful, which I doubt.  Bill has an argument against our position which I don't fully understand.  He appears to countenance quantification over a larger class than the existents that he calls the 'items'.  He claims that
Some item is a dragon 
is true.  The basis for this is not revealed.  My guess is that it might be by 'itemic generalisation' from 
Fafner is a dragon,
or some similar presumed singular truth.  So I guess the question we have to ask Bill is What are these 'items'  and what is it for an item to exist or not exist?  It seems that for Bill, but perhaps not for Ed and myself,  'exists' and 'does not exist' are perfectly plausible predicates applicable to 'items'.  He says, for example,
One can legitimately ask: What is it for a concrete contingent individual [item?] to exist? and one can expect something better than the blatantly circular, 'To exist is to be identical to something'  (my parenthesis).
He also says something I find rather strange in his characterisation of Ed's view,
Pace BV, the items in the domain of quantification admit of no existence/nonexistence contrast. Therefore, 'Something is a cat' is indistinguishable from 'Something that exists is a cat.' There is no difference at all between 'something' and 'something that exists,' and 'something' is all we need. Now 'something' is capturable without remainder using the resources of standard first-order predicate logic with identity. 'Exist(s)' drops out completely. There is no (singular) existence and there are no (singular) existents. There are just items, and one cannot distinguish an item from its existence.
The underlined sentences I find rather mysterious.  Are we really saying 'There is nothing'?  That aside, I begin to think that I may at last have grasped what he is driving at,  though I shall keep my powder dry.

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