 It is easy to see that we obtain a contradiction independently of whether we answer “yes” or “no” to this question (the argument runs more or less like in the liar paradox). Grelling’s paradox is self-referential, since the definition of the predicate heterological refers to all predicates, including the predicate heterological itself. Definitions such as this which depends on a set of entities, at least one of which is the entity being defined, are called impredicative.