The Radical vs. the Moderate Enlightenment

The most influential revisionist thesis in contemporary Enlightenment studies is the argument of the historian Jonathan Israel that the Enlightenment was not a single movement, but a contest between two distinct and opposed movements, the Radical Enlightenment and the Moderate Enlightenment. The argument, developed in a trilogy of large books — Radical Enlightenment (2001), Enlightenment Contested (2006), and Democratic Enlightenment (2011) — has had a major impact on the field, and it is now the most important framework for understanding the politics of the Enlightenment.

The thesis is also controversial. The historians who reject it — most importantly the so-called “Cambridge School” of the history of political thought (Pocock, Skinner, Tuck) and the various historians who work in the tradition of “republicanism” — argue that Israel’s distinction between the two Enlightenments is too sharp, that the thinkers of the Moderate Enlightenment were more radical than Israel allows, and that the thinkers of the Radical Enlightenment were less consistent than Israel claims. The debate between the two positions is, in significant part, a debate about how to read the political philosophy of the seventeenth and eighteenth centuries.

Israel’s Thesis

The thesis, in its broad outlines, is the following. There was, in the late seventeenth and eighteenth centuries, a single radical philosophical program — what Israel calls the Radical Enlightenment — that was developed by a small group of thinkers, most importantly Spinoza, and that was based on a commitment to universalism, to democracy, to freedom of thought, and to the secular state. The program was, in Israel’s view, the first fully modern political philosophy, and it is the direct ancestor of the modern human rights regime.

The Moderate Enlightenment, by contrast, was a more cautious and more compromising program, developed by writers who accepted some of the conclusions of the Radical Enlightenment (about religious toleration, say, or about the freedom of inquiry) but who refused to accept the more radical conclusions (about democracy, about the secular state, about the equality of women and of non-Europeans). The Moderate Enlightenment is, in Israel’s view, the philosophy of Voltaire, of Montesquieu, of the American founders, of Adam Smith, and of the mainstream of the eighteenth century. The Moderate Enlightenment was, on the whole, more influential in its own time than the Radical Enlightenment; but the Radical Enlightenment was, in the long run, more consequential for the development of modern thought and modern institutions.

The thesis depends, in large part, on the priority of Spinoza. Israel argues that the Tractatus Theologico-Politicus (1670) is the founding document of the Radical Enlightenment, and that the Ethics (posthumously published 1677) is its most important systematic expression. The arguments of these works — about the priority of reason, about the rejection of the supernatural, about the equality of all human beings, about the importance of democracy — were the basic commitments of the Radical Enlightenment, and they were taken up and developed by a small group of writers, including the French materialists (Diderot, d’Holbach, Helvétius), the British radicals (Toland, Collins, Tindal), and the German Aufklärer of the radical wing (Lessing, Reimarus, Mendelssohn).

The Moderate Enlightenment, by contrast, accepted the practical conclusions of the Radical Enlightenment only in so far as they were compatible with the existing social and political order. Voltaire, in Israel’s view, was a brilliant polemicist and a fierce critic of the established church, but he was no democrat, and his political philosophy was, in significant part, an apology for the enlightened absolute monarchy. Montesquieu, similarly, was a sharp critic of the existing French monarchy, but his political philosophy was, in significant part, an apology for the English mixed constitution and the French aristocratic republic of his own time. The American founders, in Israel’s view, were the most consistent of the Moderate Enlightenment thinkers: they accepted the principle of popular sovereignty, but they built into the Constitution a series of checks and balances that were designed to limit the scope of democratic politics.

The Critique of the Thesis

The critique of Israel’s thesis comes from several directions. The most important is the Cambridge School of the history of political thought, which has been the dominant force in the historiography of the Enlightenment for the last fifty years. The Cambridge historians — Pocock, Skinner, Tuck, and the various scholars who have been associated with them — argue that the political philosophy of the seventeenth and eighteenth centuries is best understood as a series of “languages” or “discourses” rather than as a single, coherent program. The political languages of the period — the language of civic humanism, the language of natural law, the language of commercial society, the language of rights — were not mutually exclusive, and the political thinkers of the period often moved freely among them.

The Cambridge historians also argue that the political philosophy of the period was more locally situated than Israel allows. The political language of the American Revolution, for example, was deeply shaped by the British political tradition, and the political philosophy of the American founders is best understood as a development of British constitutionalism rather than as an expression of a transatlantic “Moderate Enlightenment.” Similarly, the political language of the French Revolution was shaped by the French political tradition, and the political philosophy of the French revolutionaries is best understood as a development of the French critique of absolutism.

The Cambridge historians are not the only critics of Israel’s thesis. The historians of the French Revolution — most importantly Keith Baker and Dan Edelstein — have argued that Israel’s account of the “Democratic Enlightenment” is too intellectualist, that it neglects the role of practical political activity, of the press, and of the various social movements that were the actual carriers of the revolutionary program. The historians of the book trade — most importantly Robert Darnton — have argued that Israel’s account neglects the role of underground literature, of pornographic and satirical writing, and of the various genres that were the actual vehicles of the Radical Enlightenment in its most subversive forms. The historians of women and gender have argued that Israel’s account neglects the role of women, both as writers and as participants in the various movements of the eighteenth century.

The Significance

The debate about the Radical vs. the Moderate Enlightenment is, in significant part, a debate about the legacy of the Enlightenment. The defenders of Israel’s thesis argue that the legacy of the Enlightenment is best understood as the legacy of the Radical Enlightenment, and that the Moderate Enlightenment was, in significant part, a betrayal of the radical program. The critics of Israel’s thesis argue that the legacy of the Enlightenment is best understood as a complex inheritance, in which the radical and the moderate programs have both contributed to the development of modern thought and modern institutions.

The contemporary debate is also a debate about the contemporary relevance of the Enlightenment. The defenders of Israel’s thesis argue that the contemporary revival of the radical political philosophy — in the work of contemporary theorists of democracy, of human rights, and of the secular state — is the legitimate heir of the Radical Enlightenment. The critics argue that the contemporary revival of the radical political philosophy is, in significant part, a betrayal of the complexity of the Enlightenment, and that the contemporary world needs a more nuanced reading of the Enlightenment inheritance.

The debate about the Radical vs. the Moderate Enlightenment is, in short, a debate about the meaning of the Enlightenment for the contemporary world. The two positions are not simply academic positions; they are positions about how to read the political philosophy of the past, and they are positions about how to use that reading for the analysis of the political problems of the present. The contemporary reader who is serious about the Enlightenment will be familiar with both positions, and will use both as tools for the analysis of the political problems of the contemporary world.

The contemporary reader will also be aware that the distinction between the two Enlightenments is, in significant part, a heuristic device. The real history of the Enlightenment is more complex than any simple dichotomy can capture. The thinkers of the eighteenth century did not divide themselves neatly into two camps; they argued, disagreed, changed their minds, and produced a body of work that is too rich and too varied to be captured by any single distinction. The distinction between the two Enlightenments is, however, a useful tool for the analysis of the eighteenth century, and it has become one of the basic frameworks for the contemporary study of the Enlightenment.