The Secular Enlightenment by Margaret C. Jacob is a very erudite and authoritative study of the 18th-century European Enlightenment, taking readers on a tour including London, Paris, Berlin, Edinburgh, Vienna and Naples where the relative emphasis also partly depends on local conditions.

Many unfamiliar names appear along with the more famous, and the author also digs up some extraordinarily interesting detail. This process of secularisation shifts attention away from religion and salvation into temporal well-being in the here and now “without necessary reference to a transcendent order”. New worlds opened up both through navigation and exploration of the heavens expanding space and time with the work on geology by Buffon and Benoit de Maillet, the latter estimating the age of the Earth at 2 billion years as early as the 1730s. The new heresies are now recognisable as orthodoxy or at least mainstream in our time in terms of deism and materialism leading to atheism. The intolerance exemplified in the 17th century wars of religion also played an important background role, as did the emergence of larger cities with their clubs - including Freemasons - pubs and cafes where like-minded people could freely meet.

Many authors like Voltaire published their work anonymously or in more tolerant countries like Holland, and Voltaire regularly denied authorship of his anonymous works such as the Sermon des Cinquante, his most scathing attack on the veracity of Scriptures and which would have landed him in prison if authorship had been able to be proved. An even more scandalous book was The Treatise on the Three Impostors, these being Jesus, Mohammed and Moses, dating from about 1700 and which, despite the efforts of the censors, most people in enlightened circles had seen or read by 1750. The author explains the lengths to which censors went, including arresting booksellers and publishers. One extraordinary character is the Widow Stockdorff from Strasbourg, who “assembled just about every forbidden known at the time”, spending two years in prison in the Bastille for her activity. These books included pornographic as well as materialistic volumes, including the French edition of Fanny Hill and probably the 600-page autobiography of the Dutch free thinker Isabella de Moerloose, who taught “very godless and abominable things”, finishing her days in a prison for the mentally ill. Such was the typical price of free thought in the 18th century.

On a more practical level, the author discusses the reinvention of time and the move away from a Catholic context marked by saints’ days to a more modern conception. One culmination was the new French revolutionary calendar lasting from 1793 to 1805 - the “reign of reason and liberty”. Clocks and watches became more common, with a production in England around 1800 of 200,000 watches a year. The term “time management” was introduced into Dutch by Constantijn Huygens before 1700, and by the late 18th century we have people describing their days in more detail and punctuality becomes a virtue. On the other hand, Protestants experience a temporal burden, feeling the need to self-monitor their use of time and redeem it, lamenting time wasted on trivial pleasures - the author gives many fascinating examples of such a practice. This all leads to secular and enlightened people occupying time and space differently from the religious.

With 600,000 inhabitants, Paris was the largest city in continental Europe and provided the backdrop for many developments, but also with its own repressive royal form of censorship rather than the Catholic Inquisition. The author covers the work of Bayle, Montesquieu, Jean Frederic Bernard, Voltaire, D’Holbach and Rousseau as well as explaining the role of French Freemasonry. The next chapter moves to Scotland, especially Edinburgh with the emergence of the Scottish Enlightenment with David Hume, Adam Smith, Francis Hutcheson, Adam Ferguson, Joseph Black and James Hutton, among others. Here, the camaraderie of associations like the Select Society was critical in developing forums for debate, and the author draws on many primary sources in her detail. This group was cautious in expressing its religious views, so much so that Hume published his famous Dialogues on natural religion only after his death. The background of religious intolerance was more acute, and remained so; Thomas Aikenhead was hanged in 1697 at the age of only 20 for heresy and materialistic views - the notion of nature as sufficient and self organising, as also expressed in the writings of John Toland with a generalised background of Newtonian science. The predominance of social and political improvement is also reflected in the Edinburgh Speculative Society, founded in 1764 and continuing to this day - I became a member in 1978. Commercial links with leading thinkers were also strong in the case of Scotland.

The following chapters move to Berlin and Vienna, then Naples and Milan. Among the German thinkers covered are Christian Thomasius and Christian Wolff, then in Vienna musicians Mozart and Haydn before returning to the high enlightenment with Goethe, Schiller, Lessing, Herder, Moses Mendelssohn and Kant. Their overall outlook was pantheistic and universal, and we also find a revival of Leibniz and Spinoza. Herder wrote against slavery while providing “a philosophical foundation for the study of humankind progressing through time and space, developing language, making history. The foundation had been laid for anthropology as well as linguistics”1 (p. 198). Kant was one of the first to articulate a cosmopolitan vision of peace in 1786. Travelling on to Naples, we find that its population of 200,000 makes it second only to Paris in size. Here the author deals with lesser-known thinkers (at least to me) such as Celestino and Fernando Galiani, Pietro Giannone, Cesare Beccaria, Alberto Radicati, Antonio Genovesi and Gaetano Filangieri. Much of this work was political and economic, laying the foundations of representative democracy.

The American and especially the French revolutions mark a critical watershed, as described in the chapter on the 1790s, where Jefferson and Franklin provide an important link. Franklin formulates the universal ethical principle that “the most acceptable service of God is doing good to man”. Everything is now up for question and rethinking, with the demise of the old ecclesiastical and aristocratic order in many contexts. The author gives many contrasting views through contemporary lives, commenting on the renewed influence of the Stoic Epictetus, whose pagan naturalism is “complementary to the materialism derived from the new science” 2. The underlying dynamic and direction is how far the revolution should be taken – should it include slaves, women and the oppressed? This process took many decades to evolve and in some places encouraged and enlightened despotism. However, the power of ideals remains strong in promoting liberty, equality and fraternity, a process by no means completed in our time. The philosophes still have much to teach us, not least in terms of freedom of thought and expression for which they fought so hard. The book is an engaging and highly readable tour de force which deserves the widest circulation.

1 Margaret C. Jacob, The Secular Enlightenment, Princeton, 2019, p. 198.
2 Ibidem, p. 244.