ABSTRACT Argument about Rights can be either purely formal or substantial—meant to affect conduct. These two functions, which need different kinds of support, often become confused. The source of much confusion is the idea that rights‐language is an all‐purpose ‘moral theory’ which is in competition with others such as Utilitarianism. Since these are not really rivals but complementary aspects of moral thinking—parts of it, both of which need to be used along with many others—attempts to establish one of them as sole ruler are doomed to incoherence. The ambition to deploy an all‐purpose thought‐system is distinct from the moral motivation to change the world, and the two aims inevitably interfere with one another. Among these ‘moral theories’, however, the language of rights is specially ill‐suited for all‐purpose use. This becomes plain when philosophers, taking its adequacy for granted, conduct moral argument in terms of it alone, as if it were obviously appropriate, without background discussion. Rights‐language is of particularly limited use because it is simply the most competitive and litigious of such thought‐systems. Its win‐or‐lose formula allows no more scope for doing justice to defeated claims than a lawcourt does. For the serious conflicts of value that underlie large