Promises/Fairness/Rawls: the principle of loyalty to promises (principle of fidelity, fiduciary duty) is a special case of the principle of fairness.
A promise is an action defined by a public system of rules. (See R. Searle, Speech Acts, (Cambridge, 1969) pp. 33-42, especially with regard to promises: ch. III, pp. 57-62.)
Rule of Promise/Rawls: should be that we keep our promise, unless there are circumstances that justify an apology. It is thus at the same level as game rules as well as legal rules and statutes. Like these, they exist in a society if you keep to them more or less regularly.
Justice: whether the rule of promise is just depends on how the excusing circumstances are defined. This includes full consciousness and voluntariness. The principles of justice are applied to the practice of promise as well as to other areas.
Definition bona fide promise/Rawls: is present when the rule of promise and the practice it represents are fair. The fidelity principle means that bona fide promises must be kept.
Rule: is just a convention - on the other hand, the principle of loyalty is a moral principle that follows from the principle of fairness. The role of promises corresponds to what Hobbes ascribed to the sovereign (ruler):
Ruler/promise/Hobbes/Rawls: just as the sovereign stabilizes and maintains the system of social cohesion, so the private individuals stabilize their enterprises through their mutual word.
Problem: preliminary work, contracts: here it is the promise that should close the gap between an agreement and fulfilment. Circumstances that are conducive to the company are assumed. Co-operation is being stabilised through this. (See H. A. Prichard, "The Obligation to Keep a Promise", in Moral Obligation (Oxford, 1949), pp. 169-179.).
The discussion of promises shows that no moral requirements from institutions follow on their own. Nor does the rule of promise alone lead to moral obligations. For this we still need the principle of fairness as a premise._____________Explanation of symbols: Roman numerals indicate the source, arabic numerals indicate the page number. The corresponding books are indicated on the right hand side. ((s)…): Comment by the sender of the contribution. The note [Author1]Vs[Author2] or [Author]Vs[term] is an addition from the Dictionary of Arguments. If a German edition is specified, the page numbers refer to this edition.
A Theory of Justice: Original Edition Oxford 2005