Donkey sentences are sentences that contain a pronoun with clear meaning (it is bound semantically) but whose syntactical role in the sentence poses challenges to grammarians.^{[lower-alpha 1]} Such sentences defy straightforward attempts to generate their formal language equivalents. The difficulty is with understanding how English speakers parse such sentences.^{[lower-alpha 2]}

Barker and Shan define a donkey pronoun as "a pronoun that lies outside the restrictor of a quantifier or the if-clause of a conditional, yet covaries with some quantificational element inside it, usually an indefinite."^[3] The pronoun in question is sometimes termed a donkey pronoun or donkey anaphora.

The following sentences are examples of donkey sentences.

• "Omne homo habens asinum videt illum." ("Every man who owns a donkey sees it") — Walter Burley (1328), De puritate artis logicae tractatus longior^[4][5]
• "Every farmer who owns a donkey beats it."^[6]
• "Every police officer who arrested a murderer insulted him."

History

Walter Burley, a medieval scholastic philosopher, introduced donkey sentences in the context of the theory of suppositio, the medieval equivalent of reference theory.

Peter Geach reintroduced donkey sentences as a counterexample to Richard Montague's proposal for a generalized formal representation of quantification in natural language.^[6] His example was reused by David Lewis (1975),^[7] Gareth Evans (1977)^[8] and many others, and is still quoted in recent publications.

Analysis of donkey sentences

The goal of Montague grammar is to show how sentences of a natural language (like English) could be translated into a formal logical language, and so would then be amenable to mathematical analysis. Following Russell, it is typical to translate indefinite noun phrases using an existential quantifier,^[9] as in the following simple example from Burchardt et al:

"A woman smokes." is translated as ${\displaystyle \exists x\,({\text{WOMAN}}(x)\land {\text{SMOKES}}(x))}$^[10]

The prototypical donkey sentence, "Every farmer who owns a donkey beats it.", requires careful consideration for adequate description (though reading "each" in place of "every" does simplify the formal analysis). The donkey pronoun in this case is the word it. Correctly translating this sentence will require using a universal quantifier for the indefinite noun phrase "a donkey", rather than the expected existential quantifier.

The naive first attempt at translation given below is not a well-formed sentence, since the variable ${\displaystyle y}$ is left free in the predicate ${\displaystyle {\text{BEAT}}(x,y)}$.^[11]

${\displaystyle \forall x\,({\text{FARMER}}(x)\land \exists y\,({\text{DONKEY}}(y)\land {\text{OWNS}}(x,y))\rightarrow {\text{BEAT}}(x,y))}$

It may be attempted to extend the scope of the existential quantifier to bind the free instance of ${\displaystyle y}$, but it still does not give a correct translation.^[11]

${\displaystyle \forall x\,\exists y\,({\text{FARMER}}(x)\land {\text{DONKEY}}(y)\land {\text{OWNS}}(x,y)\rightarrow {\text{BEAT}}(x,y))}$

This translation is incorrect since it is already true if there exists any object that is not a donkey: Given any object to be substituted for ${\displaystyle x}$, substituting any non-donkey object for ${\displaystyle y}$ makes the material conditional true (since its antecedent is false), and so existential clause is true for every choice of ${\displaystyle x}$.

A correct translation into first-order logic for the donkey sentence seems to be

${\displaystyle \forall x\,\forall y\,(({\text{FARMER}}(x)\land {\text{DONKEY}}(y)\land {\text{OWNS}}(x,y))\rightarrow {\text{BEAT}}(x,y))}$,

indicating that indefinites must sometimes be interpreted as existential quantifiers, and other times as universal quantifiers.^[11]

There is nothing wrong with donkey sentences: they are grammatically correct, they are well-formed and meaningful, and their syntax is regular. However, it is difficult to explain how donkey sentences produce their semantic results, and how those results generalize consistently with all other language use. If such an analysis were successful, it might allow a computer program to accurately translate natural language forms into logical form.^[12] It is unknown how natural language users are – apparently effortlessly – agreeing on the meaning of sentences such as the examples.

There may be several equivalent ways of describing this process. In fact, Hans Kamp (1981) and Irene Heim (1982) independently proposed very similar accounts in different terminology, which they called discourse representation theory (DRT) and file change semantics (FCS), respectively.

Theories of donkey anaphora

It is usual to distinguish two main kinds of theories about the semantics of donkey pronouns. The most classical proposals fall within the so-called description-theoretic approach, a label that is meant to encompass all the theories that treat the semantics of these pronouns as akin to, or derivative from, the semantics of definite descriptions. The second main family of proposals goes by the name dynamic theories, and they model donkey anaphora – and anaphora in general – on the assumption that the meaning of a sentence lies in its potential to change the context (understood as the information shared by the participants in a conversation).^[13]

See also

• Epsilon calculus – Extension of a formal language by the epsilon operator
• Garden-path sentence – Sentence that starts in a way that a reader's likely interpretation will be wrong
• Generic antecedent – Representatives of classes in a situation in which gender is typically unknown
• Lambda calculus – Mathematical-logic system based on functions
• Montague grammar – approach to natural language semanticsPages displaying wikidata descriptions as a fallback
• Singular they – Gender-neutral English pronoun

References

Further reading

Notes

External links

• The Handbook of Philosophical Logic
• Discourse Representation Theory
• Introduction to Discourse Representation Theory
• SEP Entry
• Archive of CSI 5386 Donkey Sentence Discussion
• Barker, Chris. 'A Presuppositional Account of Proportional Ambiguity'. In Proceedings of Semantic and Linguistic Theory (SALT) 3. Ithaca, New York: Cornell University, 1993. Pages 1–18.
• Brasoveanu, Adrian. 'Donkey Pluralities: Plural Information States vs. Non-Atomic Individuals'. In Proceedings of Sinn und Bedeutung 11. Edited by E. Puig-Waldmüller. Barcelona: Pompeu Fabra University, 2007. Pages 106–120.
• Evans, Gareth. 'Pronouns, Quantifiers, and Relative Clauses (I)'. Canadian Journal of Philosophy 7 (1977): 467–536.
• Geurts, Bart. 'Donkey Business'. Linguistics and Philosophy 25 (2002): 129–156.
• Huang, C-T James. 'Logical Form'. Chapter 3 in Government and Binding Theory and the Minimalist Program: Principles and Parameters in Syntactic Theory edited by Gert Webelhuth. Oxford and Cambridge: Blackwell Publishing, 1995. Pages 127–177.
• Kamp, Hans. 'A Theory of Truth and Semantic Representation'. In J. Groenendijk and others (eds.). Formal Methods in the Study of Language. Amsterdam: Mathematics Center, 1981.
• Kitagawa, Yoshihisa. 'Copying Variables'. Chapter 2 in Functional Structure(s), Form and Interpretation: Perspectives from East Asian Languages. Edited by Yen-hui Audrey Li and others. Routledge, 2003. Pages 28–64.
• Lewis, David. 'Adverbs of Quantification'. In Formal Semantics of Natural Language. Edited by Edward L Keenan. Cambridge: Cambridge University Press, 1975. Pages 3–15.
• Montague, Richard. 'The Proper Treatment of Quantification in Ordinary English'. In KJJ Hintikka and others (eds). Proceedings of the 1970 Stanford Workshop on Grammar and Semantics. Dordrecht: Reidel, 1973. Pages 212–242.