I also ignore the distinction between 'de jure' rigidity, where the refercnce of a designator is stipulated to be a single object, whether we are speaking of the actual world or of a counterfactual situation, and mcre 'de facto' rigidity, whcre a description 'the such that Fx' happens to use a predicate 'F' that in each possible world is true of one and the same unique object (e.g., 'the smallest prime' rigidly designates the number two).