Use–mention distinction

In analytic philosophy, a fundamental distinction is made between the use of a term and the mere mention of it. Many philosophical works have been "vitiated by a failure to distinguish use and mention." The distinction can sometimes be pedantic, especially in simple cases where it is obvious.

The distinction between use and mention can be illustrated with the word "cheese":

1. Cheese is derived from milk.
2. "Cheese" is derived from the Old English word ċēse.

The first sentence is a statement about the substance called "cheese": it uses the word "cheese" to refer to that substance. The second is a statement about the word "cheese" as a signifier: it mentions the word without using it to refer to anything other than itself.

In written language, mentioned words or phrases often appear between single or double quotation marks or in italics. In philosophy, single quotation marks are typically used, while in other fields (such as linguistics) italics are more common. Some style authorities, such as Strunk and White, emphasize that mentioned words or phrases should be visually distinct. On the other hand, used words or phrases do not carry typographic markings.

The phenomenon of a term having different references in various contexts was referred to as suppositio (substitution) by medieval logicians. A substitution describes how a term is substituted in a sentence based on its referent. For nouns, a term can be used in different ways:

• With a concrete and real referent: "That is my pig." (personal supposition)
• With a concrete but unreal referent: "Santa Claus's pig is very big." (personal supposition)
• With a generic referent: "Any pig breathes air." (simple supposition)
• Metaphorically: "Your grandfather is a pig." (improper supposition)
• As a pure term: "Pig has only three letters." (material supposition)

The use–mention distinction is particularly significant in analytic philosophy. Confusing use with mention can lead to misleading or incorrect statements, such as category errors.

Self-referential statements also engage the use–mention distinction and are often central to logical paradoxes, such as Quine's paradox. In mathematics, this concept appears in Gödel's incompleteness theorem, where the diagonal lemma plays a crucial role.

Stanisław Leśniewski extensively employed this distinction, noting the fallacies that can result from confusing it in Russell and Whitehead's Principia Mathematica.

Donald Davidson argued that quotation cannot always be treated as mere mention, giving examples where quotations carry both use and mention functions.

Douglas Hofstadter explains the distinction between use and mention as follows:

Issues arise when a mention itself is mentioned. Notating this with italics or repeated quotation marks can lead to ambiguity.

Some analytic philosophers have said the distinction "may seem rather pedantic".

In a 1977 response to analytic philosopher John Searle, Jacques Derrida mentioned the distinction as "rather laborious and problematical".

• Haddocks' Eyes – Nickname of the name of a song
• James while John had had had had had had had had had had had a better effect on the teacher – Grammatically correct sentence demonstrating lexical ambiguity
• Map–territory relation – Relationship between an object and a representation of that object
• Metalanguage – Language used to describe another language
• Pointer (computer programming) – Object which stores memory addresses in a computer program
• Quasi-quotation – Linguistic device in formal languages
• Scare quotes – Quotation marks used to indicate non-standard usage
• Sense and reference – Distinction in the philosophy of language
• When a white horse is not a horse – Chinese philosophical dialoguePages displaying short descriptions of redirect targets

• Derrida, Jacques (1977) Limited Inc abc ... in Limited Inc
• Michael Devitt, Kim Sterelny (1999) Language and reality: an introduction to the philosophy of language
• W. V. O. Quine (1940) Mathematical Logic, §4 Use versus mention, pp. 23–5
• Wheeler, Samuel (2005) Davidson as Derridean: Analytic Philosophy as Deconstruction in Cardozo Law Review Vol. 27–2 November 2005 Symposium: Derrida/America, The Present State of America's Europe

• A. W. Moore (1986) How Significant Is the Use/Mention Distinction? in Analysis Vol. 46, No. 4 (Oct. 1986), pp. 173–179

• "Robert And The Use-Mention Distinction", by William A. Wisdom, c. 2002
• "On the use of Quotation Marks", by Ralph E. Kenyon Jr. PhD, 29 December 1992, Revised 21 October 1993, Published in ETC: A Review of General Semantics, Vol. 51 No 1, Spring 1994. (accessed: 26 August 2006).
• "The evolution of Confusion", talk by Daniel Dennett AAI 2009, 4 October 2009