  Needless to say, if such an account of legal principles is correct, the Separation Thesis can no longer be maintained. But many legal philosophers doubt that there are legal principles of the kind Dworkin envisaged. There is an alternative, more natural way to account for the distinction between rules and principles in the law: the relevant difference concerns the level of generality, or vagueness, of the norm-act prescribed by the pertinent legal norm. Legal norms can be more or less general, or vague, in their definition of the norm-act prescribed by the rule, and the more general or vague they are, the more they tend to have those quasi-logical features Dworkin attributes to principles. More importantly, notice that if you make the legal validity of norms, such as legal principles, depend on moral argument, you allow for the possibility that an entire legal community may get its laws wrong. Any moral mistake in the reasoning leading to a legal principle might render the conclusion about the principle unsound, and the principle itself thus not legally valid. Since there is nothing to prevent judges and other legal actors from making moral mistakes, there is nothing to prevent a result whereby an entire legal community, and for a long time, gets its laws wrong (Marmor 2011, chapter 4). Perhaps Dworkin would have not found this problematic, but others might; the idea that an entire legal community can be systematically mistaken about its own laws might strike legal theorists as deeply problematic.