Q-principle
In the Neo-Gricean approach to semantics and pragmatics championed by Yale linguist Laurence Horn, the Q-principle is a reformulation of Paul Grice's maxim of quantity combined with the first two sub-maxims of manner. The Q-principle states: "Say as much as you can." As such it interacts with the R-principle, which states: "Say no more than you must."
The Q-principle leads to the implicature that if the speaker did not make a stronger statement, then its denial is true. For instance, the inference from "He entered a house" to "He did not enter his own house" is Q-based inference, i.e. deriving from the Q-principle.
