--- title: "Presuppositions and Default Reasoning — paper by Mercer (1991)" description: "The work offers no data or numbers. 15 references, cited by 1 paper here. Some words carry meaning that survives negation." authors: ["Robert E. Mercer"] year: 1991 venue: "Lexical Semantics and Knowledge Representation" source: "https://aclanthology.org/W91-0220/" licence: "CC BY-NC-SA 3.0 (ACL Anthology, before 2016)" licence_url: "https://creativecommons.org/licenses/by-nc-sa/3.0/" summary_licence: "Elamur Cosmic License" canonical: "https://research.elamur.ai/free/en/papers/mercer-1991-presuppositions-default-reasoning-study-lexical/" --- [Elamur Research](https://md.research.elamur.ai/free/en/) · [this page in HTML](https://research.elamur.ai/free/en/papers/mercer-1991-presuppositions-default-reasoning-study-lexical/) [home](https://md.research.elamur.ai/free/en/) / [papers](https://md.research.elamur.ai/free/en/papers/) / [1991](https://md.research.elamur.ai/free/en/papers/1991/) / Presuppositions and Default Reasoning: A Study in Lexical Pragmatics # Presuppositions and Default Reasoning: A Study in Lexical Pragmatics **Authors:** [Robert E. Mercer](https://md.research.elamur.ai/free/en/authors/robert-e-mercer/) · **Year:** 1991 · **Venue:** [Lexical Semantics and Knowledge Representation](https://md.research.elamur.ai/free/en/venues/lecture-notes-in-computer-science/) ([Lecture notes in computer science 1991](https://md.research.elamur.ai/free/en/venues/lecture-notes-in-computer-science/1991/)) · **Publisher:** [Springer Science+Business Media](https://md.research.elamur.ai/free/en/publishers/springer-science-business-media/) · **Licence:** [CC BY-NC-SA 3.0 (ACL Anthology, before 2016)](https://creativecommons.org/licenses/by-nc-sa/3.0/) **Links:** [Publisher's page](https://aclanthology.org/W91-0220/) · [PDF](https://aclanthology.org/W91-0220.pdf) · [OpenAlex](https://openalex.org/W168993841) **Citations:** 6 citations (OpenAlex, 2026-10-14) · [1](https://md.research.elamur.ai/free/en/papers/mercer-1991-presuppositions-default-reasoning-study-lexical/cited-by/) in our library, of the 149,439 papers whose bibliographies we read ## Summary Some words carry meaning that survives negation. Both "My cousin is a bachelor" and, in its usual reading, "My cousin is not a bachelor" suggest that the cousin is an adult male. These presuppositions can still disappear: an added remark about a three-year-old cancels them, and a disjunction with "spinster" blocks them. Explaining when they survive is the projection problem. Earlier solutions by Karttunen, Karttunen and Peters, Soames and Gazdar tagged parts of a word's meaning as presuppositional in advance. They then removed unwanted ones with special filtering or cancellation rules. Mercer instead treats presupposing as inference by the hearer. Following Gazdar's epistemic view and Grice's maxims, the hearer guesses what a cooperative speaker must know. Each trigger word contributes default rules in Reiter's Default Logic, an extension of Carnap's meaning postulates. These rules are evaluated inside the default theory built for the whole utterance, so the context decides what survives. The work offers no data or numbers. Its value is a clean division of labour: word knowledge sits in the lexicon and general reasoning sits in the inference engine. Mercer calls this lexical pragmatics. ## Key points - The identifying test for presupposition is the negation test: an inference follows from both a simple sentence and the preferred reading of its negation. - There are two ways to cancel a presupposition: make it inconsistent with what follows, as in (2a), or use a disjunction that splits into cases each denying it, as in (2b) "bachelor or a spinster". - The paper rejects three earlier families of solutions: filtering during composition (Karttunen 1973/1974, Karttunen and Peters 1979, Soames 1979), cancellation after interpretation (Gazdar 1979), and a hybrid (Soames 1982). - Carnap's meaning postulate is strengthened from one-way implication to logical equivalence. The paper presents this as an agent-centred view of the definitions an agent holds at a given moment, not as a theory of correct definitions. - Defaults are scoped to the sentence and guarded by an LF predicate. The guard stops them firing for logically equivalent paraphrases such as "not an unmarried adult male". Figure 1 shows an ISA hierarchy where negation targets only the last feature arc. ## Interesting ideas - Treat a word's presuppositions as defaults that hold only if they stay consistent with the rest of the utterance, rather than as fixed facts filtered afterwards. - A disjunction can block presuppositions because each disjunct, read as a case, denies what the other would presuppose. - Limit the reach of defaults to one sentence, both to keep reasoning tractable and because defaults tend to act locally. - Attach defaults to the specific surface trigger through a guard, so a logically equivalent paraphrase does not fire the same presupposition. - In an ISA hierarchy, negating a concept flips only its last distinguishing feature, and everything else is inherited by default, as in "not a bachelor" or "toy dog". ## For Mova How these ideas could serve Mova, our small open language model — its files, stages and tests: - **I1** (frames): prag could emit "not a bachelor ⇒ adult male, married" as a defeasible inference that is retracted when a later clause, such as a stated age of three, contradicts it. - **I2** (world): when the text world holds an "A or B" claim, it could expand the claim into explicit cases and keep only inferences that survive in every case. - **I3** (world): default inferences from triggers could be checked against the current sentence's entities only, which keeps the derivation trace short and explainable. - **I4** (frames): key presupposition rules on the lemma and its node in the UD tree, not on the normalized logical form. - **I5** (world): the WordNet-based ontology could mark each concept's final differentiating feature, giving a principled reading for negated or modified nouns. *Our summary of the paper, in our own words — not its text. The work belongs to its authors; read it at the links above.* ## Institutions - [Western University](https://md.research.elamur.ai/free/en/universities/western-university/) — University, London, Canada · 7 works · 278 citations 📚 Shelves (4): [🖥️ Computer Science](https://md.research.elamur.ai/free/en/shelves/computer-science/) · 16,667 works · [🤖 Artificial Intelligence](https://md.research.elamur.ai/free/en/shelves/computer-science/artificial-intelligence/) · 16,194 works · [🎭 Arts and Humanities](https://md.research.elamur.ai/free/en/shelves/arts-and-humanities/) · 16,039 works · [🗣️ Language and Linguistics](https://md.research.elamur.ai/free/en/shelves/arts-and-humanities/language-and-linguistics/) · 15,891 works 🧭 Topics (2): [🧮 Reasoning](https://md.research.elamur.ai/free/en/topics/reasoning/) · 1,426 works · [😉 Implicature](https://md.research.elamur.ai/free/en/topics/implicature/) · 138 works ## Cite Cite as: Robert E. Mercer. 1991. Presuppositions and Default Reasoning: A Study in Lexical Pragmatics. Lexical Semantics and Knowledge Representation. The paper itself, not this page. BibTeX from the library's record of the work. ```bibtex @inproceedings{mercer1991presuppositions, title = {{Presuppositions and Default Reasoning: A Study in Lexical Pragmatics}}, author = {Robert E. Mercer}, booktitle = {Lexical Semantics and Knowledge Representation}, year = {1991}, doi = {10.1007/3-540-55801-2\_44}, url = {https://doi.org/10.1007/3-540-55801-2_44} } ``` - [← previous Very Large Annotated Database of American English](https://md.research.elamur.ai/free/en/papers/marcus-1991-very-large-annotated-database-american/) - [next → Reversible Machine Translation: What to Do When the Languages Don't Line Up](https://md.research.elamur.ai/free/en/papers/barnett-1991-reversible-machine-translation-what-do/) - [↑ back to papers of 1991](https://md.research.elamur.ai/free/en/papers/1991/) ## References 15 references, 1 of them with a card of ours. ↗ leads to the work, «find» searches for one we have no id for yet. 1. R. Carnap. Meaning and Necessity. Chicago University Press, 1956. [find](https://scholar.google.com/scholar?q=R%2E+Carnap%2E+Meaning+and+Necessity%2E+Chicago+University+Press%2C+1956%2E) 2. D. A. Cruse. Lezicai Semantics. Cambridge University Press, 1986. [find](https://scholar.google.com/scholar?q=D%2E+A%2E+Cruse%2E+Lezicai+Semantics%2E+Cambridge+University+Press%2C+1986%2E) 3. G. J. M. Gazdar. Pragmatics: Implicature, Presupposition, and Logical Form. Academic Press, 1979. [find](https://scholar.google.com/scholar?q=G%2E+J%2E+M%2E+Gazdar%2E+Pragmatics%3A+Implicature%2C+Presupposition%2C+and+Logical+Form%2E+Academic+Press%2C+1979%2E) 4. H. P. Grice. Logic and conversation. In P. Cole and J. L. Morgan, editors, Syntax and Semantics, v.3, Speech Acts, pages 41-58. Academic Press, 1975. [↗](https://doi.org/10.1163/9789004368811_003) 5. L. Karttunen and S. Peters. Conventional implicature. In C-K. Oh and D. A. Dineen, editors, Syntax and Semantics, v.11, Presuppositions, pages 1-56. Academic Press, 1979. [find](https://scholar.google.com/scholar?q=L%2E+Karttunen+and+S%2E+Peters%2E+Conventional+implicature%2E+In+C%2DK%2E+Oh+and+D%2E+A%2E+Dineen%2C+editors%2C+Syntax+and+Semantics%2C+v%2E11%2C+Presuppositions%2C+pages+1%2D56%2E+Academic+Press%2C+1979%2E) 6. L. Karttunen. Presuppositions of compound sentences. Linguistic Inquiry, 4:169-193, 1973. [find](https://scholar.google.com/scholar?q=L%2E+Karttunen%2E+Presuppositions+of+compound+sentences%2E+Linguistic+Inquiry%2C+4%3A169%2D193%2C+1973%2E) 7. L. Karttunen. Presupposition and linguistic context. Theoretical Linguistics, 1:181-194, 1974. [↗](https://doi.org/10.1515/thli.1974.1.1-3.181) 8. R. E. Mercer and R. Reiter. The representation of presuppositions using defaults. In Proceedings of the ~th Biennial Conference of the CSCSI/SCEIO, pages 103-107, 1982. [find](https://scholar.google.com/scholar?q=R%2E+E%2E+Mercer+and+R%2E+Reiter%2E+The+representation+of+presuppositions+using+defaults%2E+In+Proceedings+of+the+%7Eth+Biennial+Conference+of+the+CSCSI%2FSCEIO%2C+pages+103%2D107%2C+1982%2E) 9. R. E. Mercer. A Default Logic Approach to the Derivation of Natural Language Presuppositions. PhD thesis, Dept. of Computer Science, University of British Columbia, 1987. [find](https://scholar.google.com/scholar?q=R%2E+E%2E+Mercer%2E+A+Default+Logic+Approach+to+the+Derivation+of+Natural+Language+Presuppositions%2E+PhD+thesis%2C+Dept%2E+of+Computer+Science%2C+University+of+British+Columbia%2C+1987%2E) 10. It. E. Mercer. [Solving some persistent presupposition problems](https://md.research.elamur.ai/free/en/papers/mercer-1988-solving-some-persistent-presupposition-problems/). In Proceedings of the 12th International Conference on Computational Linguistics, pages 420-425, 1988. 11. It. E. Mercer. Using default logic to derive natural language presuppositions. In Proceedings of the 7th Biennial Conference of the CSCSI/SCEIO, pages 14-21, 1988. [find](https://scholar.google.com/scholar?q=It%2E+E%2E+Mercer%2E+Using+default+logic+to+derive+natural+language+presuppositions%2E+In+Proceedings+of+the+7th+Biennial+Conference+of+the+CSCSI%2FSCEIO%2C+pages+14%2D21%2C+1988%2E) 12. It. E. Mercer. Deriving natural language presuppositions from complex conditionals. In Proceedings of the 8th Biennial Conference of the CSCSI/SCEIO, pages 114-120, 1990. [find](https://scholar.google.com/scholar?q=It%2E+E%2E+Mercer%2E+Deriving+natural+language+presuppositions+from+complex+conditionals%2E+In+Proceedings+of+the+8th+Biennial+Conference+of+the+CSCSI%2FSCEIO%2C+pages+114%2D120%2C+1990%2E) 13. R. Iteiter. A logic for default reasoning. Artificial Intelligence, 13:81-132, 1980. [find](https://scholar.google.com/scholar?q=R%2E+Iteiter%2E+A+logic+for+default+reasoning%2E+Artificial+Intelligence%2C+13%3A81%2D132%2C+1980%2E) 14. S. Soames. A projection problem for speaker presuppositions. Linguistic Inquiry, 10:623-666, 1979. [find](https://scholar.google.com/scholar?q=S%2E+Soames%2E+A+projection+problem+for+speaker+presuppositions%2E+Linguistic+Inquiry%2C+10%3A623%2D666%2C+1979%2E) 15. S. Soames. How presuppositions are inherited: A solution to the projection problem. Linguistic Inquiry, 13:483-545, 1982. [find](https://scholar.google.com/scholar?q=S%2E+Soames%2E+How+presuppositions+are+inherited%3A+A+solution+to+the+projection+problem%2E+Linguistic+Inquiry%2C+13%3A483%2D545%2C+1982%2E) *Updated 1 November 2026*