Rigidifying a contingent property produces a property whose extension is fixed by the actual world and thus holds necessarily.

The second response involves moving from contingent properties like those involved in (2) and (3) to necessary properties, and in particular to what, following Plantinga in (1974), we will call an individual essence, which is a property that, necessarily, if x exists, then it has that property and, necessarily, only x has. The property being on David's right is not an individual essence of Paul, as Paul might have existed without having had it and Charles might have had it instead. But it is eas