 Rawls doesn’t go into the circumstance and conditions mentioned in the rule in any great detail, but he does note that a promise must be voluntary and deliberate. He also notes that a proper rendition of such clauses is necessary to evaluate whether the institution of promising the rule defines is just (1971: 346). The second piece of theory Rawls employs is the notion of a bona fide promise. A bona fide promise is a promise that arises in accordance with the rule of promising, when the practice [of promising] it represents is just.