The Meaning of 'Is' and Meta-Language

In 'The Morning Star is the Evening Star', the meaning of 'is' is 'is the same as', as opposed to 'exists', and to 'has as a property'.  However, it is unclear if that meaning is a 'Sense' or a 'Reference', and, in either case, how it can have both types of Meaning, problems that are even more urgent in the cases of its alternative meanings, neither of which is as determinate as is 'is the same as'.  Now, the seeming difficulty in resolving these problems without implicating the millennia of extra-linguistic controversies that have fueled the history of Philosophy, e. g. from Aristotelian Metaphysics to Heideggerian Ontology, presents a challenge to Fregean Philosophy of Language, which is often depicted as an autonomous enterprise.  Accordingly, the pervasive response of Fregeans is to purge 'ordinary language' of 'is' and 'exists', and where a suitable alternative is not available, e. g. 'lives', to resort to meta-linguistic re-formulation.  However, one indication that such a manoeuvre is inadequate is its susceptibility to the Heideggerian interpretation of it as an extra-linguistic 'forgetting of Being', an interpretation towards which Fregeans tend to be dismissive.  But, less easy for them to shrug off is the charge that the response is tendentious, on the grounds that it is disguised Platonism.  For, as is suggested by the survival of 'is' or 'exists' in the meta-language, e. g. 'there is an x such that . . .' the meaning of 'is' is now the eternal 'exists' of a privileged realm.  Now, a Platonic Form is both a Sense and a Reference, i. e. the Form of the Good is both the Sense and the Reference of the ordinary use of 'good'.  Likewise, it is not the case that meta-linguistic 'is' has no Meaning, but, rather, that it has one, and it is both a Sense and a Reference.  So, Fregean Philosophy of Language is not as presupposition-less as its advocates tend to portray it as.