In-Depth Notes on Presupposition and Entailment

Presupposition and Entailment

Definitions of Key Terms

Presupposition is the assumption made by the speaker that certain information is already accepted as true before the utterance is made. For example, in the sentence "Jane stopped smoking," the presupposition is that Jane used to smoke. Thus, it carries an implication about Jane's past behavior and assumptions about her identity.

Entailment, on the other hand, is a logical relationship where one statement necessarily follows from another. It signifies that if the first statement is true, the second must also be true. For instance, from the assertion "Jane does not smoke," one can logically infer that "Jane used to smoke."

The Relationship Between Presupposition and Entailment

Entailment establishes a connection between two propositions. For example, consider the propositions:

  1. "John forgot to call Mary."

  2. "John did not call Mary."
    In this case, the first proposition entails the second, meaning if the first is accurate, the second must be true. Another example might involve the statement "Sting is a great singer," which entails that "Sting is a singer" and also that "Sting is alive."

Presupposition Constancy Under Negation

Presuppositions exhibit a property known as constancy under negation, meaning that they remain consistent even when the proposition is negated. For instance:

  • In the assertion "Mary's dog isn’t cute," the presupposition that "Mary has a dog" remains.

  • In the expression "Everybody knows that John is divorced," the presupposition implicit is about John’s marital status, regardless of whether the claim is negated or affirmed.
    This illustrates that the presence of a presupposition persists irrespective of how the primary statement is framed.

Types of Presuppositions

  1. Existential Presupposition: These are based on definite noun phrases indicating existence. Example: "The King of Sweden turned 80 today" presupposes that the King of Sweden exists.

  2. Factive Presupposition: This type involves specific verbs that assume their content as true. Phrases like "I didn’t know he had an accident" presupposes that the accident occurred.

  3. Lexical Presupposition: Created using lexical phrases that imply certain conditions. For example, "He managed to escape" presupposes he tried to escapt.

  4. Structural Presupposition: These arise from sentence structures, particularly wh- forms. The question "When did he leave?" presupposes he left.

  5. Non-factive Presupposition: Assumptions made that the proposition is not true. An example includes "I dreamed I was rich," which presupposes the speaker was not rich.

  6. Counterfactual Presupposition: These express scenarios that contradict actual conditions, for instance, "If you were my friend…" presupposes you are not my friend.

The Projection Problem

When dealing with presuppositions, especially in complicated discourse, identifying them can be challenging. For example, if someone states: "Have you read the book, Madonna in a fur coat?" the background context is blurred by varying presuppositions and entailments that may change based on the speaker’s knowledge and implications. This is exemplified through conversational exchanges.

One strategy for handling these ambiguities is through softening presuppositions, as seen in the question, "What’s that guy doing in the parking lot?" This approach introduces less rigid assumptions and allows for more flexible interpretations of entailments and presuppositions.

Foreground vs. Background Entailments

In analyzing how information is presented, the distinction between foreground and background entailments becomes crucial. For example, in the statement "Rover chased three squirrels," the background entailment implies something occurred, while the foreground implies a more specific scenario – that Rover was indeed the one pursuing squirrels. This differentiation aids in understanding the nuances of language and implication.

Applications of Presuppositions in Advertising

Presuppositions are frequently utilized in advertising to create implicit assumptions that influence consumer perception. For instance, stating a coffee is "extremely hot" implicitly presupposes that the beverage is enjoyable and worth consuming immediately. Similarly, in a beer advertisement stressing you do not need to cross a bridge to enjoy a great beer, it presupposes that there are alternative options available nearby that are equally enticing.

Presuppositions in Legal Contexts

In the legal field, presuppositions play a critical role in shaping narratives presented in court. For instance, when an attorney asks, "How fast was the person driving when he crossed the red light?" there is an inherent presupposition that a red light was crossed, which can significantly affect the response received and the case outcome.

In summary, understanding presuppositions and entailments provides deeper insights into communication, revealing the underlying assumptions that shape meaning in language. This understanding is not only crucial for effective communication but also has practical implications across various fields such as law, advertising, and everyday interactions.