 Enlightenment thinkers rejected the religious interpretation of history but brought in their own teleology, the idea of progress—the idea that humanity is moving in the direction of better and more perfect civilization, and that this progression can be witnessed through study of the history of civilization (Condorcet 1795; Montesquieu 1748). Vico’s philosophy of history seeks to identify a foundational series of stages of human civilization. Different civilizations go through the same stages, because human nature is constant across history (Pompa 1990). Rousseau (1762a; 1762b) and Kant (1784–5; 1784–6) brought some of these assumptions about rationality and progress into their political philosophies, and Adam Smith embodies some of this optimism about the progressive effects of rationality in his account of the unfolding of the modern European economic system (1776). This effort to derive a fixed series of stages as a tool of interpretation of the history of civilization is repeated throughout the eighteenth and nineteenth centuries; it finds expression in Hegel’s philosophy (discussed below), as well as Marx’s materialist theory of the development of economic modes of production (Marx and Engels 1845–49; Marx and Engels 1848).