 Here is the substantive argument: the purposes of a legal system very commonly include the allocation of decision-making power, enabling a person or an agency not merely to take an action that they know will be treated as legally consequential, but to decide what the law is to be on some point. The law can authorise them to take an action that the law itself treats as its decision of a matter of right or duty or liability. When, for example, the U.K. Parliament enacts that ‘VAT shall be charged at the rate of 20 per cent’, the contribution to the law is that VAT shall be charged at the rate of 20 per cent.