The rule of law is considered by common consent to be a 'good thing'. It is one of those essentially contested concepts every theorist, advocate, and political protagonist wants to claim for her or his own. This is not surprising, for in common political debate 'rule of law' is a shorthand expression of important values concerning protection from tyranny and what is less often emphasised equality.1 This equality has two dimensions of state and citizen, and of personswith no special treatment accorded higher classes or status groups as was the case in feudal society. The English law of persons which, as Maitland put it, at one time comprised nobles, clerics, monks, serfs, slaves, excommunicates and outlaws2 (not to mention children and women), came to know virtually only the abstract individual as bearer of universal legal rights and duties. This transformation was part of a broader social and ideological movement, for the rule of law is the fundamental legal component of the political philosophy of liberalism; and as with all liberal concepts, at one time it had a sharp progressive cutting edge. The difficulty is that formal equal treatment of those who are substantively unequal perpetuates, and may indeed compound, substantive inequality. This understanding might have been reached by classical philosophy; if justice consists in treating equals equally and unequals unequally, as Aristotle said in the Politics, then surely it is a logically inevitable conclusion that it is unjust to treat unequals equally. But this leap requires a prior determination: that inequalities of wealth, opportunities, and educational and occupational skills are contingent and are matters of societal concern. For much of human history those inequalities were regarded as inevitable, and indeed by some people as reflecting inherent and ineradicable personal differences. Attempts to interfere with them were seen charitably as fatuous or at worst as contrary to divine or natural law. It is one of the central moral insights of socialism, which has reoriented even the politics of its opponents, that such inequalities