Entailment

In pragmatics (linguistics), entailment is the relationship between two sentences where the truth of one (A) requires the truth of the other (B). For example, the sentence (A) The president was assassinated. entails (B) The president is dead.

What is entailment?

Entailment is a concept that refers to a specific kind of relationship between two sentences. More specifically, entailment means that if one sentence is true, then another sentence would also have to be true: the second sentence would be entailed by the first sentence. 

Another way to prove entailment between two sentences is to demonstrate that if the one sentence is false, then the other sentence must also be false. Entailment is closely related to the concept of logical consequence. Within logic, the idea that if A is true, then B must be true too is nothing other than a form of entailment. 

Usage and rules

An example of entailment can be found in the following pair of sentences.

Statement A: "I will turn 28 this year;"

Statement B: "I am currently living."

Entailment is present here because the truth of A requires the truth of B: if I am not currently living, then I cannot age, and therefore I will not turn 28 this year. The truth of A requires the truth of B, and this is the very definition of the concept of entailment. 

By the same token, entailment also means that if B is false, then A is also false. If it is in fact the case that I am currently dead, then A must be false, because then I cannot reach the age of 28. Again, then, entailment is present in the relationship between A and B. 

The basic rule for entailment has been effectively captured by the above example. If two sentences X and Y are related by entailment, then this means that if X is true, then Y must also be true—or conversely, that if Y is false, then X must also be false. This is really all there is to it (you can always buy a research paper from Ultius and have one of our writers explain it to you in more detail).

Entailment - Relationship to linguistics

The concept of entailment belongs to a branch of linguistics known as pragmatics. Pragmatics is the study of how language is actually used in real, living, social situations. This is why talking about entailment can get a little philosophical, sometimes: entailment gets to something close to the core of the logical structure of language itself. If the concept of entailment did not work, then a lot of what people say to each other might turn into gibberish, since the logical structure of language would no longer hold in a meaningful way. This is why the concept of entailment may be of interest not just to linguists but also to analytical philosophers as well (in addition to essay service writers from Ultius who wrote this article). 

Entailment is related to the concepts of presupposition and implicature. Presupposition refers to a basic premise that is assumed to be true before entailment takes place. For example, the question of whether I will turn 28 this year first of all presupposes that I am real. Regarding implicature, entailment differs from this concept in that implicature only means that the truth of A suggests, and does not require, the truth of B. For example, the statement A that I am writing these words suggests the statement B that I am human. However, this may not necessarily be the case, insofar as one counts in the possibility of intelligent extraterrestrial life.