The Man in the Mirror and Belief De Se

The following can happen.  You see yourself but without self-recognition.  You see yourself, but not as yourself.  Suppose you walk into a room which, unbeknownst to you, has a mirror covering the far wall.  You are slightly alarmed to see a wild-haired man with his fly open approaching you.  You are looking at yourself but you don't know it.  (The lighting is bad, you've had a few drinks . . . .) You think to yourself

1) That man's fly is open!

but not

2)  My fly is open!

Now these thoughts or propositions are different.  For one thing, they have different behavioral consequences.  I can believe the first without taking action with respect to my fly, or any fly.  But if I believe the second I will most assuredly button my fly.  A second point is that one cannot validly infer (2) from (1). That is because (2) says more than (1). For (2) says that BV's fly is open AND that I am BV.  When I refer to myself using 'BV' I refer to myself in the third person using an abbreviation (or a name) that both I and others can use. When I refer to myself using 'I,' I refer to myself in the first person using a word that only I can use to refer to myself.

So  (1) and (2) are different propositions.  I can believe the first without believing the second.  But how can this be given the plain fact that 'that man' and 'BV' refer to the same man?  The demonstrative phrase and the proper name have the same referent. Both propositions predicate the same property of the same subject.  So what makes them different propositions?

If propositions are Russellian, then BV, all 170 lbs of him, is a constituent of both propositions, which implies that these propositions are one and the same. But the propositions are distinct as has already be shown. So they must be Fregean.  BV himself cannot be a constituent of such a proposition: he needs a surrogate entity, a Fregean sense, to stand in for him in the proposition and to represent him.  (Note that this sense is both a representative of BV and a representation of BV.)  

As noted, (2) analyzes into a conjunction of 

3) BV's fly is open

and

4) I am BV.

Here is the point at which I am flummoxed and reach an impasse.  (4) says more than

5) BV is BV.

(5) is a miserable tautology. It is a logical truth, true in virtue of its logical form. Its negation is a contradiction. (4) is in some sense 'informative,' 'synthetic.' It smacks of a certain 'contingency': might I not have inhabited a numerically different body? Might not my epistemic access to the world have been mediated by a different body and brain?  

(5) differs in cognitive value (Erkenntniswert) from (4). But I am at a loss to say what this I-sense is. It has to be a sense, an abstract item of sorts, but what is it? What is the sense of this sense?  It appears utterly ineffable. The sense of 'I' when deployed by BV is unique to him: it somehow captures his ipseity and haecceity which are of course 'incommunicable,' as a scholastic might say, to anyone else.  

How eff the ineffable?  Hegel: there is no ineffable to eff. Tractarian Wittgenstein: Es gibt allerdings das Unaussprechliche. 'There is, however, the inexpressible."