 It also follows that Hesperus exists iff \(\exists x [E(x) \land S(x)]\); and this would be challenged by Kripke (1980) and others; see the entries on  rigid-designators  and  names.  But by analyzing names as  descriptions—quantificational expressions, as opposed to logical constants (like ‘\(b\)’) that indicate individuals—Russell offered an attractive account of why the proposition that Hesperus is bright differs from the proposition that Phosphorus is bright. Instead of saying that propositional constituents are Fregean senses, Russell could say that ‘Phosphorus is bright’ expresses a proposition of the form