Israel argues that the Enlightenment was composed of two separate tendencies, a Radical Enlightenment based on the philosophies of Spinoza and Bayle, and a Moderate Enlightenment, partly based on the philosophy of John Locke. The Radical Enlightenment was dedicated to ideals of equality, democracy and universal education. The thinkers of the Radical Enlightenment strongly favored reason and science over religion. They believed that current institutions, both political and religious, including all traces of monarchy and aristocracy, would and should be swept away in a worldwide cultural and political revolution, once the common people had become sufficiently educated.

Israel believes that it was the thinkers of the Radical Enlightenment, such as Diderot, d’Holbach and Thomas Paine, whose ideas gave rise to the revolutions of the late 18th century, in particular the French Revolution. He characterizes the thinkers of the Moderate Enlightenment, such as Rousseau and Kant, as being much more conservative and anti-democratic.

Although Israel’s thesis is convincing, and the book is informative, his prose is repetitious and convoluted. He insists on inserting French phrases that could just as well be translated and includes the same lists of names (Diderot, Helvetius and D’Holbach, for example) over and over again. A Revolution of the Mind is important but not a pleasure to read.  (11/11/10)