The struggle between those who possess social power and those who do not, between freeman and slave, patrician and plebian, lord and serf, guildmaster and journeyman, in a word, oppressor and oppressed is a war fought with many and varied weapons. Of highest importance are ideas, weapons in an ideological warfare by which every class struggling to maintain its grip on the world tries to justify its position morally and rationally, while those fighting to overturn the social order produce their own self-justificatory ideology as a counter-weapon.

If the revolution succeeds, that revolutionary ideology becomes transformed into a weapon of consolidation and conservation whereby yet further revolutionary challenges to the new dominant class can be resisted. Nothing better illustrates the historical progression of such ideological weapons than the revolution that created the twentieth century market-industrial society.

The society of Europe before the seventeenth century (with the exception of certain mercantile Italian republics) was characterized by a static, aristocratic scheme of relations in which both peasants and landowners were bound to each other and to the land and in which changes in the social positions of individuals were exceedingly rare. Persons were said to owe their position in the world to the grace of God or to the grace of earthly lords. Even kings ruled Deo gratia, and changes in position could only occur by exceptional conferrals or withdrawals of divine or royal grace. But this rigid hierarchy directly obstructed the expansion of both mercantile and manufacturing interests who required access to political and economic power based on their entrepreneurial activities rather than on noble birth.