Two reasons support this conviction. First, without determinate and accessible standards of moral permissibility, there is a risk that some citizens will make larger sacrifices than what is morally required of them. When the costs involved are comparatively high, this is likely to be unfair. To illustrate this unfairness, we can consider the case of an individual who internalises the egalitarian ethos, and who takes on some grueling occupation only because she fails to recognise that, because of her personal prerogative, she would be morally justified in pursuing a more enjoyable occupation.