The concept of ‘Enlightenment’ is without doubt one of the most enduring, and at the same time most disputed notions within eighteenth-century studies. Ever since the professionalisation of humanities scholarship in the nineteenth century, the Enlightenment has been a central concern for anyone working on the history of Europe between roughly 1680 and 1800, including those who deny or strongly downplay the importance and validity of the concept. The boundaries between so-called dix-huitièmistes and scholars of the Enlightenment remain blurry until this day: for example, the main conference of the International Society for Eighteenth-Century Studies (ISECS), which takes place every four years, is also known as the International Congress on the Enlightenment.

Apart from the vast body of scholarly work in eighteenth-century studies that is implicitly connected to the notion of ‘Enlightenment’, either through its choice of subject (such as educational reform, the rise of female authorship, or political economy) or through the way in which it approaches this subject, there is also a more narrowly defined line of research that addresses the Enlightenment as a social and intellectual movement in its own right. Researchers following this line take their lead from Immanuel Kant’s seminal essay ‘Was ist Aufklärung?’, published in the Berlinische Monatsschrift of December 1784, which can be considered as one of the first attempts to theorise the Enlightenment.

It is within the latter framework that we should also place The Secular Enlightenment, written by the eminent historian Margaret C. Jacob, who has been a prominent scholar in the field of Enlightenment studies for many decades. A tenured professor of history since 1971, Jacob has made a significant contribution to the scholarly debate on European intellectual history of the last fifty years, most visibly by coining the term ‘radical Enlightenment’, which she introduced in her 1981 landmark study The Radical Enlightenment. Pantheists, Republicans and Freemasons.

Reading The Secular Enlightenment, one is immediately struck by the immense amount of knowledge that Jacob brings to bear on her topic. Both geographically and in terms of the themes discussed, the scope of her book is very broad. We are taken on a tour of practically all the European intellectual hotspots of the day, from Edinburgh in the north to Naples in the south, and Vienna in the east. Thematically, the book ranges from in-depth discussions of the ideas of prominent philosophes, such as Voltaire and Adam Smith, to a more general account of the fundamental changes in how people of all ranks experienced time and space from the late seventeenth century onwards.

The guiding principle behind all these observations on Enlightenment thinking and its overall impact on human life, as already suggested by the title of the book, is the notion of the secular, which is almost as disputed as the term Enlightenment itself. What is more, the two concepts have an intimate relationship that leads us directly to the heart of the aforementioned scholarly debate about the meaning of the Enlightenment. Jacob’s stance in this debate is clear. Already in the opening lines of her book, she writes: ‘The Enlightenment was an eighteenth-century movement of ideas and practices that made the secular world its point of departure. It did not necessarily deny the meaning or emotional hold of religion, but it gradually shifted attention away from religious questions towards secular ones’ (1). By thus presenting the processes of Enlightenment and secularisation as inseparable, and to a large degree even synonymous, Jacob aligns herself with those who see the Enlightenment as a radical and irrevocable rift in European intellectual history, which caused the birth of Western modernity. Opposed to this are the views of scholars like David Sorkin, who in his 2011 monograph The Religious Enlightenment. Protestants, Jews, and Catholics from London to Vienna defended the position that ‘the Enlightenment, at its heart, was religious in nature’.

Based on the diverse examples that are brought together in this book, one has to admit that Jacob makes a compelling case for the existence of a secular Enlightenment. Roughly speaking, the first three chapters lay the general basis for her argument by showing how the conception of human life changed fundamentally in the eighteenth century, making it in the end more directed towards the here and now and less to divine providence and the afterlife. Chapter 1 focuses on the spatial dimension and includes a discussion of how colonial expansion, together with technological innovation, led not only to a much broader but also a more concrete idea of the world in which people lived. Chapter 2 explores the notion of time. Here technological developments, such as the invention of the pocket watch, are discussed in conjunction with philosophical debates on the age of the earth and the emergence of the idea of linear time. Chapter 3 connects these conceptual changes to the lives of ‘ordinary’ citizens, defined by Jacob as ‘literate, reasonably educated eighteenth-century people’ (66). Using their diaries and other private sources, she brings many of them to life, showing their strong inclination towards the secular.

Chapters 4 to 7 discuss the meaning and content of the Enlightenment in specific geographic areas, or within specific linguistic communities, starting with the most famous ‘high’ francophone Enlightenment of Voltaire, Diderot, Rousseau, and their likes in ­chapter 4, followed by the Scottish Enlightenment of David Hume and Adam Smith in chapter 5. Chapter 6 and 7 focus on the generally lesser-known developments in the German-speaking world and on the Italian peninsula, taking the local contexts of Berlin, Vienna, Naples, and Milan as their starting point. Although the overview of ideas and key texts that is given in these four chapters is both impressive in its scope and lucid in its presentation, the endless parade of philosophical and theological quarrels on Newtonianism, state politics, the place of the church, economy, morality, and human rights, also lacks somewhat in urgency. With their focus on ‘Great Names’ and major trends, these chapters read like intellectual history in the more traditional sense: a discussion of original thinking and its progress through time that takes the value and societal impact of this thinking as self-evident.

The book’s final chapter addresses yet another topos of eighteenth-century studies, namely the issue of how the Enlightenment as an intellectual movement is related to the revolutionary events that took place in the Atlantic world in the last few decades of the eighteenth century, starting with the American revolution and ending with Napoleon’s appointment as first consul in 1799. Jacob makes it clear that the connection between the two events, although undeniable, was also highly ambivalent. The democratic ideals of the French Revolution were at first welcomed in the new republic of the United States, but after the Reign of Terror their popularity decreased significantly. In the German and Italian lands, the lifespan of these ideals was even shorter, and anti-Enlightenment spirits took over in the blink of an eye.

Margaret Jacob has always had a special interest in the Dutch Republic. Already in 1992, she co-edited the volume The Dutch Republic in the Eighteenth Century. Decline, Enlightenment, and Revolution, together with Wijnand Mijnhardt. It is thus no surprise that the Dutch Republic receives ample attention in The Secular Enlightenment. Jacob writes extensively about the importance of the Dutch book trade for the international circulation of new, enlightened ideas, and on how the French Huguenots living in the Dutch Republic significantly contributed to the emergence of the radical Enlightenment in Paris around the mid-eighteenth century. Given this generous treatment, her discussion of the revolutionary period in the Netherlands is somewhat disappointing. The Batavian Revolution and its aftermath are summarised in less than two pages, leaving out many noteworthy developments and giving the overall impression that this was an episode that does not deserve any serious attention by international scholars.

All in all, Jacob’s latest book offers a good synthesis of her ideas on the Enlightenment, developed over the course of her long and outstanding academic career. Though mainly an intellectual history, The Secular Enlightenment also has a sharp eye for the social, political, and cultural contexts in which the new ideas on nature, man, society, and state came about, paying special attention to the prominent role of masonic lodges in the spread of Enlightenment thinking. This makes the book a suitable reading for those who have little to no knowledge of eighteenth-century history, although they should be aware that Jacob’s distinctly secular perspective portrays only one side of the medal. Specialists of the Enlightenment period on the other hand will discover a treasure-trove of materials and ideas, but not the kind of grand new insights or interpretations as in some of Jacob’s earlier works. Be that as it may, The Secular Enlightenment can still be considered as an impressive scholarly work, which deserves a spot on the bookshelf of any scholar interested in the eighteenth century.