Many accounts of the relationship between faith and the sciences in the nineteenth century adopt an approach that concentrates on the cosmological and ontological implications of scientific theories such as uniformitarian geology or evolution by natural selection. In this intriguing series of case studies, John Haller takes a different tack, choosing instead to frame his inquiry around epistemological questions. This means that, rather than the rise of naturalistic explanatory frameworks, the loss of personal faith, questions about the historical reliability of the Bible, or the cultural authority of science, for Haller the key issue is the possibility of definitive knowledge.

Haller is a distinguished scholar of medical history, and his previous studies of alternative medicine and homeopathy displayed a sophisticated engagement with epistemology. His recent work on Emanuel Swedenborg also shows a keen interest in theological issues. Fictions of certitude combines these approaches, using nine case studies to interrogate how Victorian thinkers navigated theological controversies and epistemic uncertainties, shorn of the confident Enlightenment belief that all of existence was knowable, measurable and comprehensible. It begins with Auguste Comte and explains his attempt to arrive at certain knowledge through positivist philosophy, which relied on empirical evidence and dispensed with metaphysics. Comte's application of positivism to human nature helped to establish the field of sociology, but it also convinced him that humans had an innate need for the spiritual guidance and morality provided by organised religion, and attempted to fill the vacuum caused by the declining influence of Catholicism with a secular ‘religion of humanity’. The next chapter, on John Henry Newman, is one of the book's most interesting. Newman is the only theologian studied, and Haller interprets Newman's conversion from Anglicanism to Catholicism as an attempt to navigate matters of faith and uncertainty. Subsequent chapters cover the sociologist Herbert Spencer, the naturalist Alfred Russel Wallace, the biologist Thomas Henry Huxley, philosophers John Fiske and William James, the sociologist Lester Frank Ward, and Paul Carus, the author, publisher and pioneer of comparative religious studies. Some of these studies will be of particular interest to scholars of religion, especially the chapters on Fiske, Ward and Carus, who, while not unknown, have not received anywhere near the level of detailed study that they deserve. Haller has certainly placed future scholars in his debt by locating these figures in an epistemological context alongside better-studied thinkers and providing helpful information on primary sources. Those with a particular interest in the relationship between science and religion will also appreciate the chapter on Huxley. Haller discusses and dismisses the ‘conflict thesis’, which holds that science and religion are two separate fields, inevitably in conflict. In one of the book's standout sections, he also explains carefully the appropriation of Darwinism as a secular ideology with a meaning that stretched far beyond a biological theory.

Nevertheless, the volume does have some drawbacks. The number of studies is fairly large, and each is relatively short, at around twenty pages. Fewer, more detailed studies, particularly of the lesser known figures, would have made for a more compelling read. Although there is an overarching concern with epistemic certainty, the book lacks a cohesive thread or developed thesis. This is exacerbated by the lack of a conclusion; rather than a synthesis, Haller's final chapter instead points at other figures and movements from the period that he finds interesting, such as theosophy. Indeed, this chapter underlines that Haller appears to have chosen his subjects precisely because he found them interesting. Readers are likely to agree that they are interesting thinkers, but it is frustrating to note Haller's passing mention of figures such as James McCosh, who would have provided a more interesting counterpoint to some of the other case studies. The manuscript would also have benefitted from closer editing. For instance, in the course of one sentence the names of three philosophers are misspelled: Francis Hutcheson is called ‘Francis Hutchinson’, Thomas Reid is ‘Thomas Read’ and Granville Sharp is ‘Granville Sharpe’ (p. 69). One final concern is Haller's use of ‘intelligent design’. In his chapter on Wallace, co-discoverer of evolution by natural selection, Haller suggests that Wallace believed that ‘a Higher Intelligence (i.e., Intelligent Design)’ was the origin of human intellect and morality (p. 96). Similarly, in his discussion of the conflict thesis, Haller suggests that non-Darwinian thinkers believed in a natural world ‘with its archetypes eternally present and forever fixed by Intelligent Design’ (p. 113). Intelligent design, used in this manner, refers to a movement that began in the United States in the 1980s. Its use here is decidedly anachronistic and the fact that the book's blurb is provided by Michael A. Flannery, who has published work with the Intelligent Design non-profit Discovery Institute that attempts to claim Wallace as the spiritual godfather of intelligent design, will certainly raise some eyebrows. However, if approached with caution, this volume does have plenty to offer scholars of religion and intellectual life in the nineteenth century.