One can see the task of international law as threefold: to safeguard the irreducible minimum of sovereign equality, to promote greater equality to the extent possible, and to try our best to promote equality, while justifying the differences and inequalities in a fair way. There are several arguments that can be categorized as "meta-arguments" attempting to justify differences generally. Another meta-argument is Thomas Franck's formulation of the criteria for the legitimacy of a rule of international law, which we shall call "the secondary rule meta-argument". In addition to meta-arguments, human intelligence has also produced many specific arguments targeting particular issues, although they do not work well once taken out of the particular contexts. These arguments for exceptions do not include, of course, the attempts to make a new rule of customary international law. The arguments for differing rights and obligations seem to succeed more often in treaties and conventions than in general customary international law.