In philosophy and rhetoric, the principle of charity requires interpreting a speaker's statements to be rational and, in the case of any argument, considering its best, strongest possible interpretation. In its narrowest sense, the goal of this methodological principle is to avoid attributing irrationality, logical fallacies or falsehoods to the others' statements, when a coherent, rational interpretation of the statements is available. According to Simon Blackburn "it constrains the interpreter to maximize the truth or rationality in the subject's sayings."
Neil L. Wilson gave the principle its name in 1958–59. Its main area of application, by his lights, is determining the referent of a proper name:
How should we set about discovering the significance which a person attaches to a given name? […] Let us suppose that somebody (whom I am calling "Charles") makes just the following five assertions containing the name "Caesar." […]
(1) Caesar conquered Gaul. (Gc)
(2) Caesar crossed the Rubicon. (Rc)
(3) Caesar was murdered on the Ides of March. (Mc)
(4) Caesar was addicted to the use of the ablative absolute. (Ac)
(5) Caesar was married to Boadicea. (Bc)
Willard Van Orman Quine and Donald Davidson provide other formulations of the principle of charity. Davidson sometimes referred to it as the principle of rational accommodation. He summarized it: We make maximum sense of the words and thoughts of others when we interpret in a way that optimises agreement. The principle may be invoked to make sense of a speaker's utterances when one is unsure of their meaning. In particular, Quine's use of the principle gives it this latter, wide domain.
Since the time of Quine et al., other philosophers have formulated at least four versions of the principle of charity. These alternatives may conflict with one another, so which principle to use may depend on the goal of the conversation. The four principles are:
A related principle is the principle of humanity, which states that we must assume that another speaker's beliefs and desires are connected to each other and to reality in some way, and attribute to him or her "the propositional attitudes one supposes one would have oneself in those circumstances" (Daniel Dennett, "Mid-Term Examination," in The Intentional Stance, p. 343).