This first response is from o4-mini.
In pragmatics what are presuppositions and implicatures?
In pragmatics, both presuppositions and implicatures are ways in which speakers convey—and listeners infer—information that goes beyond the literal meaning of utterances. They differ, however, in how that extra information is encoded and recovered.
Presuppositions
A presupposition is an assumption that a sentence (or utterance) takes for granted as background information. If the presupposition isn’t already established in the context, the utterance typically feels odd, misleading, or infelicitous.
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Definition: A proposition P is a presupposition of sentence S if, whenever S is used felicitously, the speaker and hearer must both accept P as true.
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Triggers: Certain words or constructions automatically carry presuppositions, for example:
- Definite descriptions: “The king of France is bald.” presupposes “There is a king of France.”
- Factives: “I regret that I ate too much.” presupposes “I ate too much.”
- Change-of-state verbs: “She stopped smoking.” presupposes “She used to smoke.”
- Temporal clauses: “Before he arrived, we had dinner.” presupposes “He arrived.”
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Projection behavior: Even in negated, questioned, or conditional forms, presuppositions tend to “project”—that is, they remain assumptions regardless of operators around them.
- “Did you stop smoking?” still presupposes “You used to smoke.”
- “If she stopped smoking, she will feel better.” presupposes “She used to smoke.”
- “She didn’t regret leaving.” still presupposes “She left.”
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Example:
“John’s sister is a doctor.”
- Presupposes: “John has a sister.”
- As a result, if you don’t already believe John has a sister, the utterance feels strange or misleading.
Implicatures
An implicature is information implicitly conveyed by a speaker, which the listener infers based on principles of cooperative communication rather than any explicit presupposition.
There are two main types:
- Conversational implicatures (Gricean implicatures)
- Conventional implicatures
1. Conversational Implicatures
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Definition: Inferred meanings arising from the assumption that speakers generally follow conversational maxims (Quantity, Quality, Relation, Manner) laid out by Grice (1975).
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Mechanism: Listeners reason: “If the speaker meant X, they would have said so; since they didn’t, they must mean Y.”
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Example (Quantity):
A: “How was the movie?” B: “Well, the cinematography was nice.”
Implicature: B didn’t comment on plot or acting ⇒ perhaps the plot/acting was not so good.
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Example (Relation):
A: “Do you want to go to the concert?” B: “I have to work early tomorrow.”
Implicature: B is declining the invitation, because they’re using relevance to imply they can’t attend.
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Cancelability: Conversational implicatures can be explicitly “canceled” without contradiction:
“The movie was great—and by the way, the acting was fantastic too.”
2. Conventional Implicatures
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Definition: Meanings tied to particular words or constructions that are not part of the truth‐conditional content but are still conventionally attached to them.
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Properties:
- Encoded in the lexicon or grammar (unlike conversational implicatures, they do not depend on context-driven inference).
- Non‐cancellable (or at least far harder to cancel felicitously).
- Non‐projecting in the same way as presuppositions, but they persist even under negation.
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Common triggers:
- But, yet, however (contrast)
- Even (scalar emphasis)
- So (conclusion)
- Because (reason)
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Example:
“She’s poor but happy.”
- Truth‐conditions:
¬(rich(she)) ∧ happy(she) - Conventional implicature: Contrast between “being poor” and “being happy.”
- Truth‐conditions:
Key Differences
| Aspect | Presupposition | Conversational Implicature | Conventional Implicature |
|---|---|---|---|
| Source | Triggered by certain words/structures | Inferred via Cooperative Principle | Lexical/grammatical |
| Dependence on context | Requires context to be satisfied | Requires context and maxims | Largely context‐independent |
| Cancelable? | Generally non‐cancelable (except by defeating) | Cancelable | Typically non‐cancelable |
| Projection behavior | Projects under negation, questioning, etc. | Does not project; tied to particular context | Persists under negation but not “projecting” like presuppositions |
Why They Matter
Understanding presuppositions and implicatures is crucial for:
- Pragmatic inference: How we read between the lines in everyday conversation.
- Discourse analysis: Tracking which assumptions are taken for granted and how speakers manage shared information.
- Computational linguistics: Designing systems that can interpret user intent beyond the literal text.
By distinguishing what must already be known (presuppositions) from what is conveyed by conversational strategy (implicatures), we gain insight into the rich, subtle ways language users communicate more than meets the eye.
This second response is from o3.
Expand this comparison to also compare logical implication to these two
Below is an expanded three-way comparison that brings logical implication into the picture alongside presuppositions and implicatures. After a quick refresher on what logical implication is, I contrast the three phenomena along the dimensions that typically matter in pragmatics and logic.
1. What is logical implication?
In formal semantics and logic, implication (often symbolized “→”) is a truth-functional relation between propositions.
- Definition (classical logic): ϕ → ψ is false only when ϕ is true and ψ is false; in all other truth-value combinations it is true.
- Speaker commitment: Uttering a statement that contains an implication (e.g. “If it rains, the streets will be wet”) commits the speaker to the truth of that whole conditional—but not to the truth of its antecedent or consequent individually.
- Context-independence: The truth value depends purely on the propositions involved, not on what interlocutors mutually assume or infer.
2. Side-by-side comparison
| Feature / Question | Presupposition | Conversational Implicature | Conventional Implicature | Logical Implication |
|---|---|---|---|---|
| How introduced? | By specific triggers (definites, factives, “stop,” etc.) | Inferred via Grice’s Cooperative Principle and maxims | Encoded meaning of certain connectives/expressions (“but,” “even”) | By logical form (connectives like “if…then,” “⊃”) |
| Part of truth-conditions? | No (backgrounded) | No (inferred) | No (side meaning) | Yes (conditional’s truth value) |
| Speaker commitment | Speaker acts as though presupposition is already true | Speaker suggests but need not be committed if implicature later canceled | Committed to content plus the conventional side meaning | Committed to the truth of the entire implication (ϕ → ψ) |
| Can it be canceled outright? | Generally non-cancelable (must be “accommodated” or the utterance crashes: “Oops, sorry—John doesn’t actually have a sister”) | Yes (“The soup was warm—but I don’t mean it was bad”) | Normally non-cancelable without contradiction (“#She’s poor but happy—no contrast intended”) | Not cancelable without changing the proposition; you can reject it, but you cannot assert it and deny it simultaneously |
| Projection under negation / questions? | Projects: “Did you quit?” presupposes you used to smoke | Does not project: negating or questioning typically removes the implicature | Survives negation: “She isn’t poor but happy” still conveys contrast | Negated wholesale: “¬(ϕ → ψ)” is simply a different proposition |
| Relies on shared context? | Yes—must be accepted or accommodated | Yes—derived from expectations about relevance, quantity, etc. | Minimal—relatively context-insensitive once the trigger is used | No—purely logical truth values |
| Test for presence | Survival test (“Stop smoking” vs. “Did you stop smoking?”) | Cancelability & calculability tests | Lexical replacement (“but” → “and”) removes the contrast | Truth-table and entailment tests |
| Typical example | “John’s dog is asleep.” ⇒ presupposes John has a dog. | “It’s getting late.” (in reply to an invitation) ⇒ implies “I should go.” | “She is small but strong.” ⇒ conventional contrast. | “If the alarm rings, there is a fire.” ⇒ logical implication. |
3. How they interact (quick notes)
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Logical form vs. pragmatic enrichment
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You can embed a presupposition trigger inside a material conditional:
“If the king of France is bald, we need new barbers.” The conditional truth value is classical, but the presupposition (“France currently has a king”) still has to be accommodated—or else the sentence feels odd.
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Implicature on top of implication
- Saying “If you finish your thesis, I’ll buy you dinner” often implicates the speaker believes the antecedent is uncertain (Quantity/Relevance). The implicature disappears if you add “…and even if you don’t, I’ll still buy you dinner.”
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Presupposition vs. logical entailment
- “John regrets leaving” presupposes “John left,” but it does not logically entail “John left” in the truth-functional sense (because under negation—“John doesn’t regret leaving”—the truth of “John left” is still taken for granted).
4. Quick mnemonic
- Presupposition: “Assumed in advance.” It must already be in the common ground (or swiftly get there).
- Implicature: “Implied by pragmatics.” It’s worked out by cooperative reasoning and can be withdrawn.
- Implication (logical): “If-then formal link.” It’s built into the proposition’s structure and evaluated truth-functionally, independent of conversational cooperation.
Keeping these distinctions straight helps disentangle what a sentence asserts, what it takes for granted, and what it merely suggests.
There is a continuation in this other post.
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