I wonder if I've been changed in the night?  Let me think.  Was I the same when I got up this morning?  I almost think I can remember feeling a little different.  But if I'm not the same, the next question is 'Who in the world am I?'  Ah, that's the great puzzle!  ~Alice In Wonderland~

Caterpillar:  Who... are... you?

Alice:  Why, I hardly know, sir.  I've changed so much since this morning, you see...

Caterpillar:  I do not see.  Explain yourself.

Alice:  I'm afraid I can't explain myself, you see, because I'm not myself, you know.

Caterpillar:  I do not know.

Alice:  I can't put it any more clearly, sir, because it isn't clear to me.