NYRB: "The label 'the Enlightenment,' complete with definite article, did not enter common usage until well after the eighteenth century--in English not until the twentieth. Intellectually the Enlightenment is betst thought of as a loose constellation of ideas--a Venn diagram with many areas of intersection but no union of all the sets. Furthermore, whatever ideas and practices it gave birth to hardly provided a fixed, unchanging matrix for modernity. These ideas and practices were repeatedly challenged and reworked over the subsequent centuries. [...] At best (or worst) the Enlightenment laid a theoretical foundation on which others later built."