1) Could we reconstruct Rawls´ argument for the connection between the rule of promising as establishing the practice as such and the "meaning" (p.304) of the concept as a special case of the principle of fairness?
2) What is the ultimate upshot of his definition of the relationship between natural duties and the principle of fairness and, on the other hand, between oblgations and the principle of fairness? Cf. p.295-296 and p.301-303. What confuses me in particular whether natural duties are to depend on an explcit volition (295-296) or not (301-303). Perhaps this is namely the distinction between the two. In any case, it will be useful, if we could discuss this issue.
3) Rawls often mentions H.L.A. Hart and his understanding of Natural Law. Could you perhaps hint at alternative conceptions of natural duties, that other philosophers have put forth or, more generally, could you offer a brief general discussion of the topic ? (Question to Ana, although, of course, everybody can contribute, if they have anything to say).