W. V. Quine borrows the principle of charity from Neil Wilson, but modifies and enriches its content to fit into his naturalistic philosophy and epistemology. While Wilson ties this principle to the notion of truth, Quine’s attempts in finding a ground for it lead him to the concept of common rationality shared by all human beings, which is ultimately what makes communication, as the basis of our social life, possible. According to the paper's argument, three other expressions, that is, the principles of psychological plausibility, empathy, and projection, which Quine uses in the contexts akin to that of the principle of charity, are not but different terms for one basic idea. Given the ties between the principle of charity and rationality, Quine's wide use of the principle and its affiliated notions proves that rationality is a central, often neglected, idea in his philosophy. The paper begins with an introductory account of the brief explanation Wilson gives of the principle of charity. Then it spells out four concepts or principles of charity, psychological plausibility, empathy, and projection showing how these four notions or principles basically express the same thing. Examining the relation of these last three principles with the principle of charity and rationality, the paper's main objective is to highlight the centrality of common rationality in Quine's philosophy, despite the common view that Quine is purely engaged with semantical aspects of Language.
