What can I refer to? This chair that I'm sitting on, perhaps... but then, whilst there's surely something there (some actual stuff, or else my bum would not be so comfortable) and whilst I'm certain that calling it "a chair" is adequate for ordinary purposes, I'm not quite sure what precisely I've thereby referred to (as I'm not even sure that "is a chair" is a definite predicate expression) or even, therefore, if I've actually referred to anything in particular (to some definite thing; rather than, rather fuzzily, to some adequately delineated stuff). I'm not even sure that I can refer unambiguously to myself, with that word "I" (even though, as a substantial dualist, I do believe that I've an individual essence), since I'm not entirely sure that that word isn't also, in this language, a bit vague... Still, there does seem to be something for which that problem (of such demonstratives being fuzzily specified) won't arise: It seems clear that Everything can be referred to unambiguously. (So it's quite interesting that many philosophers, having accepted that logic is set-theoretical, entertain serious doubts about that:)
I am old; in 2003, at the age of 40, I was published in the British Journal for the Philosophy of Science, but since then I've done little. Blogging since 2007, my main involvement was via the Philosophers' Carnival, which moved to Facebook.