If the preceding line of thought has merit, there are constraints of substantive intelligibility on the proper delineation of the domain moral standards. Often, although perhaps not always,these constraints will require some suitable connection to what are intelligibly regarded as human interests. And, indeed, such constraints looks as though they form part of the
explanation for Hart’s second feature, i.e. immunity fr
om deliberate change. For if morality
could just consist of ‘social vetoes’ that float free from
any connection with human well-being, then it is not at all clear why moral norms could not be the product of deliberate change. Now, in fact it is not quite true that each and every moral standard is immune to deliberate change. One reason Hart overlooks this is that the possibility of such change isperhaps clearest in the case of critical morality and, as I mentioned, Hart fails to keep the distinction between critical and social morality firmly in mind throughout this chapter. So,for example, the legal enactment of a speed limit can make it the case that conduct that was not morally wrong prior to that enactment immediately becomes wrong.
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Still, it remains true that morality is not subject to change by
mere
fiat or veto; deliberate change can only be effected against the background of standards, not all of which are the product of human choice, that confer that sort of moral significance on the individual or collective decision, a sin the speed limit case.