Consider what kind of authority [can be ascribed to] any principle which it open to us to choose to regard as authoritative or not. I may choose for example to observe a regimen of asceticism and fasting ... for reasons of health ... What authority such principles possess derives from the reasons for my choice. Insofar as they are good reasons, the principles have corresponding authority; insofar as they are not, the principles are to that same extent deprived of authority. It would follow that a principle for the choice of which no reasons could be given would be a principle devoid of authority. I might indeed adopt such a principle from whim or caprice or from some arbitrary purpose ... but if I then chose to abandon the principle whenever it suited me, I would be entirely free to do so.