Between secularization and reform brings together an international group of intellectual historians and philosophers to investigate the purported relationship between the Enlightenment and declining religiosity. In their introduction, Anna Tomaszewska and Hasse Hämäläinen argue that while we have moved on from the myth that the Enlightenment was fundamentally unChristian, the claim that the era was one of profound secularisation remains a ‘well-entrenched bias’ (p. 9). Their own historiographical summary suggests that during the Enlightenment religious debate moved from confessional competition towards the overlapping concerns of justifying theism using reason and articulating the ‘core of religion’ as a set of ‘ethical precepts’ (p. 8). The best of the essays that follow offer stimulating discussion about the religious, though decreasingly Christian, quality of much Enlightenment thought.

In recent publications Jeffrey Burson has demonstrated his mastery of the debate over defining (the) (religious/global/secular/national etc) E/enlightenment(s). His chapter confidently outlines the relevant historiographical points of contention for the collection, as well as his own argument for our need to incorporate study of eighteenth-century theological controversies. Focus on debates within Christianity illuminates so much besides our more commonplace focus on radical attacks from without, and informs Burson's argument that much of what is deemed secularisation occurred as the unintended consequence of controversies amongst theologians rather than between them and radical philosophes. With echoes of Carl Becker's famous thesis, Dominic Erdozain argues that the view of passion-riddled human nature professed by many Enlightenment thinkers demonstrates that ‘Enlightenment anthropology was suffused’ with the Christian idea of original sin (p. 56). The argument raises a key interpretative issue. If eighteenth-century thinkers professed a view of human nature informed by their Christian heritage but which was not entirely the same and which was described without appeal to that heritage's language, is that a continuity or discontinuity? To Erdozain, ‘whatever they chose to call it, they still had a doctrine of sin’ (my italics; p. 65). To my mind, this position lacks sensitivity to the realities of historical change and projects an almost cloying sense of what counts as Christian.

Damien Tricoire argues that the French Revolution was the ‘triumph of theocracy’ and not the victory of secular liberalism (p. 71). Earlier philosophes and Revolutionaries alike were anticlerical, but they believed that the basis of morality and the new politics was a natural law that had authority because it was divine. Tricoire discusses a varied cast of authors – Voltaire, Quesnay, Rousseau, Mably and several of the key Revolutionaries – to back up this claim. In arguing against a secularising view of the French Enlightenment and Revolution, he does not, however, emphasise the implication that it remained an age of deChristianisation. By contrast, Wiep van Bunge details how in the eighteenth-century Dutch Republic there was little engagement with radical Enlightenment philosophy and very little deChristianisation or secularisation. Instead, the century saw the full confessionalisation of society. The late seventeenth-century radical Dutch Enlightenment fizzled out and was succeeded by a religious culture that was staid and, while open to incorporating advances in natural theology, largely unchanging. Like the other chapters in part i, this is a confidently composed argument covering a lengthy period, written by a scholar in charge of their materials.

After these more general assessments, the chapters in parts ii and iii delve into case studies. In these latter sections, the purportedly overriding themes of Between secularization and reform get lost beneath some, occasionally excellent, narrower discussion. Gianni Paganini examines the writings of the French soldier, notary and memoirist Robert Challe (1659–1721), a consumer of early modern Europe's clandestine irreligious texts. In composing his own deist position, Challe took Malebranche's philosophy beyond its Christian limits, extrapolating to their fullest extent its ‘univocity of moral notions, primacy of wisdom and therefore of reason, regularity and simplicity of divine ways’ (p. 138). In his own act of deChristianisation, he excised Malebranche's theological framing. Paganini presents Challe as an example of how it was possible to develop a radical deist philosophy in the late seventeenth century based on sources other than Spinozism.

Mathias Sonnleithner examines how French Revolutionaries, between 1791 and 1794, constructed Rousseau and Voltaire as religious thinkers and used them as ‘key witnesses’ on religious matters (p. 167). The two philosophes provided the ideological underpinning to the Revolutionaries’ attempts to purify religion and ‘return it to its origins’ as a deistic universal natural religion (p. 191). Sonnleithner argues this was true for both the Cult of the Supreme Being but also the Cult of Reason. Moreover, many Revolutionaries were not Machiavellian proponents of a civil religion that supported inculcated political virtue, but devout theists who used to use politics to ‘enforce their religious convictions’ (p. 169). Reassessing his Système de la nature, Hasse Hämäläinen argues that while the purported atheist Baron d'Holbach rejected institutionalised revealed religion, he did not completely reject deism. Existing religions were tools of oppression exploiting the enduring superstitious quality of human nature. D'Holbach accepted, however, that it was hypothetically possible to have a dogma-free rational religion conducive to happiness. On the existence of God, d'Holbach was not a dogmatic atheist but an agnostic thinker articulating a Humean scepticism about the inability of reason and experience to draw up conclusive arguments one way or the other.

Ian Leask details how William Molyneux pushed back on his social superior John Locke's command that Molyneux abandon the radical John Toland to civil punishment on account of Toland's heretical opinions. Molyneux stood up to Locke by utilising Lockean arguments that civil authorities should not decide on matters of religious belief, drawing out parallels between Toland and Locke's own experience of persecution. The chapter details an episode that will be of interest to scholars of English and Irish intellectual history circa 1700, but Leask's attempt to link it to a ‘tectonic shift’ in European thinking about religious freedom is tacked on at the end (p. 233). Diego Lucci's chapter is a helpful primer on his excellent recent work on Locke's biblical theology. Locke was informed by the Socinian and Arminian traditions, but his position was ultimately the result of thoughtful, independent close reading of Scripture. Lucci surveys succinctly the main aspects of Locke's theology: revelation as an infallible and sufficient moral and religious guide; the role of good works and faith in salvation; the bodily death of the soul and its subsequent resurrection; and his Messianic but non-Trinitarian Christology. The link in the final paragraphs to Locke's ironic role in the Enlightenment secularisation myth, however, is an afterthought.

Stephen Palmquist puts forward a speculative argument about how the ‘roots of Kant's theory of enlightened religion’ (p. 267) can be found not only conceptually but also historically in the Quaker sect that emerged in seventeenth-century England, at least via German Pietism. Kant's religious vision gave ‘philosophical expression’ to a position that the ‘early Quakers had preached at the Enlightenment's very outset’ (p. 291). Palmquist is a cogent writer and expert commentator on Kant, but as a historical argument the chapter relies upon vague appeals to the ‘conceptual resonances’ between Quakerism and Kantian religious thought (p. 279). Anna Tomaszewska undertakes a comparison between Johann Christian Edelmann (1698–1767) and Immanuel Kant on the issue of the Incarnation. Both authors maintained that ‘it is our rationality that takes us closer to God’ and both sought to ‘purify Christianity from the kind of supra rationem dogmas that are best represented by the doctrine of Incarnation’ (p. 314). Tomaszewska denies that such aims prove they had anti-religious motives: they pursued a universal rational religion that avoided the pitfalls of dogma and institutionalisation. Like Burson, she stresses that any secularisation inherent in their views was an unintended consequence of genuine attempts at reforming Christianity from within.

The collection ends with Wojciech Kozyra's argument that Kant was the only major German Enlightenment figure who claimed that ‘to realize its essence, Christianity must entirely discard its Jewish heritage’ (p. 319). Kozyra's Kant is not a proponent of a universal rational religion, but a theorist of ‘Christianity as a religion and a theory of Judaism as an anti-religion’ (p. 319). Kant is one of two major Enlightenment-era proponents of Marcionian thought, named after the Church Father Marcion of Sinope, who rejected the Old Testament in its entirety. The other is the English deist Thomas Morgan, who Kozyra conjectures was the source of Kant's view.

The topic is an important one. Debate will run on though, not least because the kaleidoscopic quality of the source material – the character of religious developments across Enlightenment Europe – means we are increasingly just rejigging the pieces into new formation. Noticeably, several chapters stress that the era was not one of secularisation due to continued religious commitments but, in the process, they imply that it was an era of deChristianisation. Several chapters suggest that secularisation did take place, but as the unintended consequence of genuine attempts at reforming Christianity. One factor occluding our own further enlightenment is the use of straw men. Here, the definition of the era as one of secularisation in the opening pages of Margaret Jacob's The secular Enlightenment (2019) is used as a hook onto which counterarguments are hung, but without addressing her more substantive claims about changes to European culture in the long eighteenth century. Still, there are several excellent chapters in this collection, especially those written by experienced scholars immersed in the literature of several languages.