Two arguments about rules are usually told apart. One, made famous by G. K. Chesterton's parable of the fence in The Thing (1929), says that a rule whose use one cannot see should not be cleared away until its reason is known. The other, as old as Machiavelli's Prince, says that a ruler who wishes to keep his state must know how to break a rule when necessity requires it. This article asks what it costs to remove a rule whose reason is unknown, what it costs to break a rule for an exception, and who pays. Reading Chesterton's opening paragraphs and chapters VIII, XV and XIX of The Prince (Marriott's translation) in full, it finds that neither text gives the licence its slogan suggests. Chesterton puts a burden of knowledge on the remover and also licenses departure from a rule by those who understand it. Machiavelli licenses the exception only in a particular shape: done at once, not repeated, and with its reproach carried by someone other than the ruler. It then sets both readings beside two synthetic ARCHON scenes, modern summaries written for a platform: a prohibition on changing a sales image met by a request to change it, and a principle that unscheduled goods are returned. In both, the reason for the rule is not given in the scene, and the platform's readings turn the question of reason into questions of scope, authority and who is blamed. The pairing is offered to the debate in organisation studies over rules that outlast their purposes; it does not decide whether any rule in the scenes should stand.
