 While logically proper names (words such as “this” or “that” which refer to sensations of which an agent is immediately aware) do have referents associated with them, descriptive phrases (such as “the smallest number less than pi”) should be viewed merely as collections of quantifiers (such as “all” and “some”) and  propositional functions  (such as “x is a number”). As such, they are not to be viewed as referring terms but, rather, as “incomplete symbols.” In other words, they are to be viewed as symbols that take on meaning within appropriate contexts, but that remain meaningless in isolation.