 (Though he regarded this transformation as effected by a sort of tacit legislation.) If sound, the Midas Principle holds in general and not only with respect to morality, as Kelsen makes clear. Suppose then that the Income Tax Act penalizes overdue accounts at 8% per annum. In a relevant case, an official can determine the content of a legal obligation only by calculating compound interest. Does this make mathematics part of the law? A contrary indication is that it is not subject to the rules of change in a legal system—neither courts nor legislators can repeal or amend the law of commutativity. The same holds of other social norms, including the norms of foreign legal systems. A conflict-of-laws rule may direct a Canadian judge to apply Mexican law in a Canadian case. The conflicts rule is obviously part of the Canadian legal system. But the rule of Mexican law is not, for although Canadian officials can decide whether or not to apply it, they can neither change it nor repeal it, and the best explanation for its existence and content makes no reference to Canadian society or its political system. In like manner, moral standards, logic, mathematics, principles of statistical inference, or English grammar, though all properly applied in cases, are not themselves the law, for legal organs have applicative but not creative power over them. The inclusivist thesis is actually groping towards an important, but different, truth. Law is an open normative system (Raz 1975 [1990: 152–154]): it adopts and enforces many other standards, including moral norms and the rules of social groups. There is no warrant for adopting the Midas Principle to explain how or why it does this.