This paper aims to discuss a well-known concept from argumentation theory, namely the principle of charity. It will show that this principle, especially in its contemporary version as formulated by Donald Davidson, meets with some serious problems. Since we need the principle of charity in any kind of critical discussion, we propose the way of modifying it according to the presupponendum—the rule written in the sixteenth century by Ignatius Loyola. While also corresponding with pragma-dialectical rules, it also provides additional content. This will be termed the dialectical principle of charity, and it offers a few steps to be performed during an argument in order to make sure that the participants understand each other well and are not deceived by any cognitive bias. The meaning of these results could be of great significance for argumentation theory, pragma-dialectics and the practice of public discourse as it enhances the principle of charity and makes it easier to apply in argumentation.