Can scientific inquiry and religious devotion be mutually supportive endeavours? Or is there an essential incompatibility between the faith that religion demands and the scepticism that science requires? The war between science and religion has been fought on many fronts, with numerous white flags waved and peace treaties signed and ripped apart. A weary observer might ask, why frame the debate in such stark terms? The concepts ‘religion’ and ‘science’ connote dizzyingly diverse forms of thought and activity, both across history and in our own time. Any conclusive answer to how these two entities might be ‘essentially’ related seems improbable, and perhaps inevitably reductive. It is difficult, to put it mildly, to provide a complete account of what ‘science’ or ‘religion’ is. Many historians of science, such as Mario Biagoli in his excellent Galileo's Instruments of Credit (2006), have thus found it preferable to focus on particular points of abrasion or mutual support in the historical record between practices and ideas that we can recognize as ‘scientific’ or ‘religious’ (or both).

These conceptual difficulties notwithstanding, the science-and-religion conversation shows no sign of abating. The establishment of the Ian Ramsey Centre for Science and Religion at Oxford in 2009 suggests that still more debate lies ahead. Happily, some fascinating research – such as Roger Trigg and Justin Barrett's work on the cognitive underpinnings of religious experience – has appeared in recent years in this context. In this spirit, two recent books – Eric Dietrich's Excellent Beauty and Roger Wagner and Andrew Briggs's The Penultimate Curiosity – revisit, and reframe, the ancient quarrel between science and religion. Dietrich deals with the problem of accounting for what ‘science’ and ‘religion’ are by stating precisely how he understands each concept; some readers, however, might lament the thinness of a definition that attempts to distill religion to its essential elements. Wagner, a religious painter, and Briggs, a professor of nanomaterials at Oxford – who appears briefly in his book, in flashback, as a ‘devout research student’ at the Cavendish Laboratory in Cambridge – take a near-opposite approach (p. 439). They assemble a compendium of religious and scientific thinkers that takes us from the Ionian philosophers to the contemporary primatologist Frans de Waal, aggregating such a breadth of examples that the book delivers the (necessarily misleading) impression of having dealt with ‘religion’ and ‘science’ in their totality. Both books come from university presses but seem to have a general readership in view, justifying the broad approach and the conversational tone of each.

In Excellent Beauty, Dietrich argues that scientific inquiry and fundamentalist religion are ‘inimical’, not least because religions insist on making factual claims that science often undermines. People should look for wonder and metaphysical grandeur in the unsolved, and perhaps unsolvable, mysteries of science, not in the precepts of religion, he suggests. Dietrich upturns the simple view that religious practice is ‘unnatural’ (solely the product of cultural construction) and that science is merely the work of describing, decoding and disenchanting the natural world. He encourages us to see religion as the ‘natural’ consequence of evolved psychological dispositions. Meanwhile, he invites us to regard certain scientific and metaphysical conundrums with reverence.

To flesh out his proposal that religion is a ‘natural’ human phenomenon – a capability like speaking a language or making music – Dietrich draws on ideas from the evolutionary biologist David Sloan Wilson (one of his colleagues at Binghamton University) and the philosopher Daniel Dennett. Wilson proposes that religion evolved as a group-bonding mechanism. Dennett suggests that the belief in the supernatural that forms the basis of much religious thinking was not directly selected for, but instead stems from other evolved cognitive traits. These traits include predispositions to over-recognize human faces, to over-recognize agents (a cognitive heuristic that leads us to think, for example, that rustling leaves signal another animal's movements rather than a stray burst of wind), and to generate explanations, sometimes fictional ones, for events that occur. Dietrich synthesizes these evolutionary accounts of religion to conclude, polemically, that ‘religions are completely natural illusions’, possessing depths and mysteries that are merely ‘chimerical’ (p. 147). The claim that religion is ‘in our genes’ seems, to Dietrich, to strike a fatal blow against religion, unmasking all systems of belief as fictions. He does not flag the high degree of controversy that surrounds Wilson's multi-level selection theory – many biologists doubt that natural selection at the group level can have had much effect on evolution – but the same complaint could be made of many recent books on evolution aimed at the general reader.

Dietrich's clear and often witty style, and his penchant for quips that needle believers – such as his aside that Jesus’ crucifixion ‘wasn't much of a sacrifice’ because Jesus didn't permanently die – suggest his talents as a polemicist (p. 156). At other moments, his blunt approach perplexes even his sympathetic readers. He concludes that philosophy ‘has made no progress since Aristotle’, appealing to the fact that philosophers cannot agree upon a single ultimate reason why slavery is morally wrong: is slavery wrong because it violates our duties to others, as deontologists say, or because it brings about unhappy consequences, as consequentialists argue? (pp. 144–145). But internal disagreement does not mean that a discipline is stalled (one could formulate a similar attack on any of the sciences), and surely we can judge slavery wrong for multiple reasons, with these plural reasons supporting – rather than undermining – the fundamental insight that slavery is immoral. Similarly, readers might wince at bald claims such as ‘No religion told us that racism is bad’, an assertion that partakes of reckless simplicity in its attempt to describe how cultural and ethical shifts occur in large populations, and which does not consider, for one thing, the large intellectual, ethical and rhetorical contributions made by the teachings of Quakers, Baptists, Jews and other religious sects in the American abolition and civil rights movements (p. 159).

Dietrich is on firmer ground when he introduces us to the philosophical conundrums that he calls ‘excellent beauties’ – such as the problem of consciousness, the riddle posed by the mathematical fact that some infinities are larger than other infinities, and ongoing puzzles in cosmology and quantum mechanics. Despite the book's title, Dietrich does not flesh out an aesthetic account of the kind of beauty that he claims for these philosophical mysteries. He limits himself to stating that ‘profundities’ are ‘intrinsically’ beautiful, and that the themes of ‘possibility, open-endedness, opportunity’ that such mysteries express are, ‘simply put’, beautiful (pp. 149–150). With his talk of mystery and profundity, it sounds at times as if he is thinking of the sublime, albeit an intellectualized variant that brings into focus the limits of human comprehension.

Awe in response to the beauty of science also runs through Wagner and Briggs's The Penultimate Curiosity, an elegantly designed volume filled with illustrations, including reproductions from Wagner's paintings. The book's main proposition is that human inquiry about the natural and physical world has frequently ‘swum in the slipstream’ of an ‘ultimate curiosity’ about the nature of the world and all contained within it (p. 411). Wagner and Briggs, with roving curiosity of their own, examine hundreds of figures, over thousands of years, who have pursued scientific knowledge alongside metaphysical or religious convictions.

That countless scientists and philosophers throughout history have been spurred by religious motives is true but uncontroversial. The potentially controversial aspect of Wagner and Briggs's thesis is their claim that there exists a ‘human need to make sense of the world as a whole’, rather than in part, or provisionally, in response to local needs (p. 411). This type of ‘ultimate’ curiosity rests upon the assumption that the natural world can be comprehended as a unity, perhaps with some rational scheme apprehensible in its composition. By weaving together ideas from scores of societies and cultures, Wagner and Briggs invite the reader to see a broad stretch of religious and scientific history as similarly unified. The consequences of such an approach are mixed. In depicting hundreds of disparate thinkers as somehow involved in the same conversation concerning the nature of the universe, Wagner and Briggs invite stimulating parallels between locales as far-flung as Victorian England and eleventh-century Iran, but assuming a shared ‘configuration’ of ‘ultimate curiosity’ risks tamping down local colour and sources of motivation that are not so easily subsumed into the ‘slipstream’ thesis (p. 411).

The fact that Wagner and Briggs are able to enfold so many stories into the ‘slipstream’ rubric suggests the looseness of this theme as an organizing principle. Yet the book's scope is one of its achievements. The work stands as a lively, if partial, anthology of key moments in the history of science, offering concise treatments both of well-known figures (Avicenna, Galileo, Darwin) and of more obscure characters (Al-Kindi, Georg Joachim Rheticus, Henry Wentworth Acland). This breathless tour, sped on by perplexingly short chapters – many of which end with cliffhanger remarks such as ‘after Ibn al-Haytham's death, this kind of suspicion was to take a more radical turn’ (p. 142) – leaves the reader occasionally disoriented, whiplashed across time and locale, futilely turning to the inside cover for a list of principal personages (there is none). Occasionally, Wagner and Briggs pause to elucidate particular moments: the chapters on the seventeenth-century Oxford experimental philosophers (among them Robert Boyle) and on Darwin, for instance, brim with local detail. Had they employed this method throughout the book, and with a greater ratio of analysis to summary, they might have been able to defend a stronger version of their ‘slipstream’ thesis. Nonetheless, this volume is an exciting display of erudition, packed with thought-provoking anecdotes and clear explanations of major scientific, religious and philosophical concepts.