Definition:
Entailment is a semantic relationship between two propositions where if the first proposition is true, the second must also be true. For example, “The cat is on the mat” entails “Something is on the mat.” Entailment is a truth-conditional relationship — it holds regardless of context, speaker intention, or pragmatic inference.
In-Depth Explanation
Entailment is fundamental to how meaning works in language. It differs from implicature (what is suggested but not logically guaranteed) and presupposition (what is assumed to be true for a sentence to make sense).
Examples:
| Sentence A (entailing) | Sentence B (entailed) | Relationship |
|---|---|---|
| She killed the spider. | The spider is dead. | Entailment ✓ |
| He is a bachelor. | He is unmarried. | Entailment ✓ |
| She ran quickly. | She ran. | Entailment ✓ |
| It’s raining. | You should bring an umbrella. | NOT entailment (pragmatic inference) |
Key test: Entailment is tested by negation. If you negate sentence A, the entailment to B disappears:
- “She didn’t kill the spider” → The spider may or may not be dead (entailment cancelled)
- Compare with presupposition: “She didn’t stop smoking” still presupposes she was smoking (presupposition survives negation)
Types of entailment:
- One-way entailment: A entails B, but B does not entail A. (“She ate an apple” entails “She ate something,” but “She ate something” does not entail “She ate an apple.”)
- Mutual entailment (equivalence): A entails B and B entails A. (“She is my sister” ↔ “I am her sibling” — roughly equivalent.)
Relevance to language learning:
Entailment relationships help explain why certain vocabulary errors cause miscommunication (“I killed the plant” implies it’s dead — if you didn’t mean that, use a different verb). Understanding entailment also helps learners grasp the precise meanings of hyponyms and hypernyms: “rose” entails “flower” but not vice versa.
Related Terms
See Also
Research
- Chierchia, G., & McConnell-Ginet, S. (2000). Meaning and Grammar: An Introduction to Semantics (2nd ed.). MIT Press. — Clear introduction to entailment and related semantic relations.
- Saeed, J. I. (2016). Semantics (4th ed.). Wiley-Blackwell. — Broader coverage of semantic theory including entailment, presupposition, and implicature.