selfreferent

Self-referent, or self-referential, is an adjective describing statements, symbols, or processes that refer to themselves or to their own category. In formal disciplines, self-reference occurs when an expression makes reference to itself, either directly or via a descriptive encoding. This phenomenon can generate paradoxes or illuminate the limits of systems.

In logic and mathematics, classic examples include the Liar Paradox and Gödel's incompleteness theorem, which rely on constructing self-referential statements through diagonalization. Recursion and fixed points are formal manifestations of self-reference in computation and mathematics. In linguistics and philosophy, self-reference appears in indexicals and discoursive acts: pronouns like I or this sentence refer to the speaker or to the utterance itself. Autological words are self-descriptive, such as “short” if the word is short, whereas heterological terms do not describe themselves.

In literature and media, self-reference is a stylistic device known as metafiction or self-referential fiction, where works draw attention to their own status as artifacts or reference their own creation within the story. Greek paradoxes, computer languages that include self-referential constructs, and memes that quote their source also illustrate the concept.

The term self-referent is often used interchangeably with self-reference or self-referential, though in some contexts it functions as a noun describing a thing that refers to itself. Related topics include paradox, recursion, autology, and the diagonal lemma.