Difference Between Entailment and Presupposition

Key Difference – Entailment vs Presupposition
 

When we hear an utterance, we usually try to understand not only what the words mean, but what the speaker of those words intends to convey. Entailment and presupposition are two pragmatic elements that help us in this. The key difference between entailment and presupposition is that entailment is the relationship between two sentences whereas presupposition is an assumption made by the speaker prior to making an utterance.

What is an Entailment?

Entailment is the relationship between two sentences/propositions, where the truth of one proposition implies the truth of the other since both of them are involved with the meaning of words. It’s the sentences, not speakers that have entailments. Entailments also depend on the meaning of the sentence, not the meaning of the context.

For example,

1. The terrorists assassinated the king.
2. The king died.
3. The terrorists assassinated someone.

b) and c) are true because sentence a) is true. Thus, their truth depends on the meaning of the utterance.

What is a Presupposition?

A presupposition is something that the speaker assumes to be the case prior to making an utterance. It’s the speakers, not the sentences that have presuppositions.

For example, if someone tells you, ‘Jane’s sister got married’, there’s an obvious presupposition that Jane has a sister.

There are several types of presuppositions.

Existential Presupposition:

The speaker presupposes the existence of the entities.

Ex:

Marie’s house is new.

• Marie exists.
• Marie has a house.

Factive Presupposition:

Certain verbs or constructions indicate that something is a fact.

Ex:

I regret believing him.

• I believed him.

I’m glad it’s over.

• It’s over.

Lexical Presupposition:

The speaker can convey another meaning using one word

He called me again.

• He called me before.

She gave up smoking.

• She used to smoke.

Structural Presupposition:

Use of certain words and phrases makes some presuppositions.

When did you call her?

• You called her.

Why did you buy this dress?

• You bought a dress.

Non- factive Presupposition:

Certain words indicate that some things are not true.

I pretended to agree with her.

• I did not agree with her.

She dreamt she was rich.

• She is not rich.

Counterfactual Presupposition:

It implies that what is presupposed is not true, and the contrary is true.

If he hadn’t been my friend, I wouldn’t have helped him.

• He is my friend.

What is the difference between Entailment and Presupposition?

Meaning:

Entailment: Entailment is the relation between sentences or propositions.

Presupposition: Presupposition is an assumption a speaker makes prior to making an utterance.

Speakers vs Sentences:

Entailment: Sentences have entailments.

Presupposition: Speakers have presuppositions.

Truth:

Entailment: The negation of the first sentence will affect the truth of the second sentence.

1. The king was assassinated.

• The king died.

2. Negation: The king was not assassinated.

• The king died. →  not true.

Presupposition: The negation of the first utterance may not affect the second sentence.

1. Her car is new.

• She has a car.

2. Negation: Her car is new.

• She has a car.→ presupposition is not changed.