The Polo theory of existence

It's thin, circular, and has a hole in it.  At least according to the latest argument from the Maverick, though the final attribution is my own summary of Bill's view, rather than his.  Ed Ockham has a very nice reply.

It's quite interesting that Bill is persisting in this through argument when it's clear (to me at least) that we are standing at the intersection of logic and language that lies at the foundation of argument, if I can put it in that oblique way.   He says

On the thin theory, 'An F exists' means the same as 'The concept *F* is instantiated.'

He sees this as a thesis about the nature of existence that thinists would want to defend, also by argument.   I'm not sure this is the right way of looking at it at all.  I see it as a recipe for the elimination of the verb to exist.  The general form 'An F exists' can always be replaced by 'The concept F is instantiated', or, better still, the plain old Anglo-Saxon, 'there is an F'.   But this form is harmless.  The singular form, 'a exists', where 'a' is a proper name, is potentially harmful.  But it can always be avoided because, at least in formal argument, every proper name must be introduced in the context of a general existential assertion.  'There is an F' introduces a scope (a block of statements) in which we can say 'let this F be denoted by 'a'', where 'a' is a new name that does not appear elsewhere in the development. Within this block the name 'a' can be used freely.  There is no need to assert 'a exists'.   Indeed, it's interesting to note that without the Latinate to exist (from exsistere, to step forth, literally ex+sistere, out+to stand)  English has no form for expressing this:  'a is', perhaps, but this seems to invite 'a is what?'  However, one can say, pointing simultaneously,  'there is a', and, seeing for himself, one's listener can interpolate 'there is some object; it's to be called 'a' from now on'.  This understanding is beneath language, as it were.  The general existential assertion that opens the scope becomes a premise of the argument.  Alternatively, as in most mathematical arguments, it may be proved.   Budding mathematicians are taught early on that you must first prove an existential assertion before introducing a name.  'Let n be the least number that satisfies p' has to be preceded by a proof that there is such a least number.  This can go wrong in two ways:  there may be no numbers that satisfy p; or there may be some such numbers, but no least one. Failing to observe this rule of argument gets your proof into trouble and you into trouble with your tutor.   I don't see why philosophical argument need be any different.