Generations of Reason examines the role of reason in the lives of three generations of an English family of Lockean Christians, tied in a matrilineal line from the Enlightenment to the Victorian era: the Lindseys, the Frends and the De Morgans. Their understanding of reason was rooted in John Locke’s philosophy. In contrast to the Continental tradition, it did not oppose scriptural revelation but was based on a linguistic view of reason concerned with clear connections between words and their proper meanings. Joan Richards skilfully weaves together richly contextualized personal stories, exploring these families’ commitment to reason and how its nature, power and limits were redefined between generations. The culmination of decades of research, the book delivers a captivating story of knowing and believing stretching from the mid-eighteenth century to the end of the nineteenth.

The story starts in the middle with the wedding of Augustus De Morgan and Sophia Elizabeth Frend in the registrar’s office in 1837. After an efficient introduction, the book proceeds chronologically in three parts. Part 1, ‘Divining reason’, takes us back to the eighteenth century. The story of reason began with the friendship between Cambridge-educated men, archdeacon Francis Blackburne and young parish minister Theophilus Lindsey, and their shared struggles with the Anglican Church’s conditions of their ministry. They perceived the Thirty-Nine Articles as discriminatory, man-made doctrine that diverted from biblical Christianity and imposed restrictions on the power of God-given human reason. Focusing on the first couple of the saga, formed through Lindsey’s marriage to Blackburne’s stepdaughter Hannah Elsworth in 1760, Richards analyses the centrality of the liberal-minded, inclusive and individualist concept of reasoned religion to their lives and occupation. Alongside intriguing insights into their daily routines, the story traces Lindsey’s path to anti-Trinitarianism, efforts to accomplish (reason-driven) changes in the Anglican Church, resignation and dissenting experience, leading to his opening of the Unitarian chapel on Essex Street in London in 1774. The spotlight then moves to William Frend, a ‘Cambridge-educated fallen Anglican’ (p. 73) who befriended Lindsey in the late 1780s. Analysing Frend’s life in the wider political context (French Revolution, English reaction), Richards illustrates his transformation from a Cambridge mathematics tutor and Anglican minister into ‘a ragingly radical Unitarian’ (p. 57). The chapters reveal the individuals’ internal worlds (emotional struggles with conversion), student life and careers within the social hierarchy in Cambridge colleges, memories of William Paley’s classes, travel experience and the circumstances of the trials that led to Frend’s banishment from Cambridge in 1793.

Part 2, ‘Defining reason’, tells the story of the second generation, marked by the marriage of Frend and Lindsey’s niece, Sarah Blackburne, in 1808. This encompasses their daughter Sophia, friendships (Lady Byron, Augustus De Morgan) and the Unitarian community network challenging the Anglican establishment. Richards opens with Frend’s 1790s exile in London, where he worked to tie mathematical and theological reasoning into his concept of human reason defined by limits and spiritual glimpses. The story then moves to Frend’s daughter Sophia. Few surviving materials document the lives of Hannah Lindsey and Sarah Frend, but Sophia’s autobiographical memoirs, correspondence, book and nursery journals sustain fascinating insights into the world, thoughts, network and activities of a female member of the family. We learn about Sophia’s upbringing in a diversity-welcoming household, the commitment to exercise powers of reason and open-mindedness, the experience of grief that instilled her rational investigation of the afterlife and the activities of Unitarian women. In 1827, Frend introduced the Cambridge-educated mathematician Augustus De Morgan to his household. Following Augustus’s journey from Anglicanism into London’s scientific community (Charles Babbage, John Herschel, George Peacock, William Whewell), Richards describes the politics involved in the founding of radical institutions (UCL, the Royal Astronomical Society), and Augustus’s efforts to shape the mathematical professorship at the new, non-residential secular university, teaching students to reason through mathematics as an alternative to theology. The final chapters neatly illustrate the friendship and courtship between Sophia and Augustus, as they actively engaged in the social world of the Royal Astronomical Society and shared an interest in a ‘newly expansive vision of a transcendent world of mind,’ pushing the understanding of human reason beyond the limits of the ‘static confines of Frend’s Georgian world’ (pp. 250–1).

Part 3, ‘Dividing reason’, analyses Augustus’s and Sophia’s endeavours within the gendered spheres of their Victorian world after their wedding in 1837, demonstrating the intergenerational commitment to reason. As religious and social diversity expanded and the English world entered a secular Victorian era in which mathematics replaced theology as a purview of reason and religion moved to the private sphere, Sophia and Augustus embraced reason as a tool of progress. Sophia explored the expansive powers of reason through investigations of the mind via phrenology, mesmerism and spiritualist experiments. Augustus did so through mathematics and logic. Richards also shows their commitment to reason in parenting and activism (philanthropy, girls’ education, the anti-slavery movement). The saga closes with a nod to the next generation and the epilogue surprises with a discussion of the different worlds of two neighbours, Augustus De Morgan and Charles Darwin.

This well-informed, deeply researched intellectual history also intersects history of science, philosophy, religion, everydayness, gender, childhood, experiences, emotions, relationships and social, cultural and institutional history. Although the family’s women left fewer historical traces than their male counterparts, Richards recognizes their important roles. Hannah, Sarah and Sophia might not have been scientific heroes, nor were they rebellious feminists raising their voices against the patriarchy, yet they recognized and exercised their own powers and aspired to make most of the sphere of their influence. Elaborating on their commitments to reasoned lives, the book informs us about the forms of male and female social and intellectual agency in the past. Richards’s highly readable story will engage audiences interested in the history of mathematics, logic and astronomy, as well as those who enjoy historical insight into people’s experiences.