Historic China and pre-industrial Europe were both once typed as rigid societies with their population more or less frozen into fixed social groupings. Since in both cases the trend of research has altered this view, one cannot help wondering why it ever prevailed. The present revision in Chinese studies is the more dramatic in being a return to the view of Quesnay, namely, that Confucian ideals guaranteed a constant social circulation: men of merit could rise in the world, but their sons, if they were inept, would sink. In medieval and early modern European studies there has been a steady shift away from emphasis on hereditary fixity to recognition that very considerable currents of social mobility may exist within a stable social structure.

In both fields writers had begun by relying on ideals of order, rather incautiously, as a clue to actual custom. Confucian philosophy and ethical doctrine, it is true, gave rise to Quesnay's happy guess, but when this was discarded as doubtful, scholars fell back on legal texts. Here they found ideals of order expressed in an array of distinctions of juridical status. Instead of still postulating that these were mere lines of demarcation between groups, lines that a man could cross, they chose to regard them as effective barriers to mobility.