Full Idea
In Kripke's puzzle about belief, the subject has two distinct mental files about one and the same object.
Gist of Idea
Puzzled Pierre has two mental files about the same object
Source
comment on Saul A. Kripke (A Puzzle about Belief [1979]) by François Recanati - Mental Files 17.1
Book Reference
Recanati,François: 'Mental Files' [OUP 2012], p.221
A Reaction
[Pierre distinguishes 'London' from 'Londres'] The Kripkean puzzle is presented as very deep, but I have always felt there was a simple explanation, and I suspect that this is it (though I will leave the reader to think it through, as I'm very busy…).