 Karttunen (1973) presented a taxonomy of embedding constructions that divided them into three classes: plugs, holes and filters. Plugs comprise a class of predicates and operators which Karttunen claimed block the projection of presuppositions, while holes are a class of predicates and operators which allow presuppositions to project freely. So, for example, since “told that” is a plug, according to  Karttunen,[14]  (25) is predicted not to presuppose that there is a King of France. On the other hand, since “perhaps” is a hole, (26) is predicted to presuppose that there is a King of France.