Tanya Luhrmann, Watkins University Professor of Anthropology at Stanford University, has spent much of the last thirty-five years researching across various cultures and religions how people experience gods and spirits. How God Becomes Real: Kindling the Presence of Invisible Others is the culmination of this research. It is an anthropological study of religious practice and experience, drawing primarily on Luhrmann's extensive ethnographic fieldwork of the last three and a half decades and supplemented by psychological experiments and analysis. This is, nevertheless, a very important book for philosophy of religion. Luhrmann's detailed ethnography and careful analysis should inform philosophical debates around religious experience; philosophers engaged in the turn to lived religion will find Luhrmann's studies of religious communities across multiple continents and diverse religious traditions an invaluable resource.

The book is split into an introduction and seven chapters, along with a brief note on methods and a set of short bibliographic essays for each chapter at the end. This latter section offers a wealth of resources for the interested reader, which may be especially useful for philosophers less familiar with other religious studies disciplines. This is representative of Luhrmann's clarity and readability: she successfully sets out her arguments clearly and precisely, while still producing engaging and entertaining prose. Luhrmann's descriptions of her ethnographic research are particularly evocative, helping the reader to get a sense of the various communities discussed.

Luhrmann begins chapter 1, ‘The Faith Frame’, with the foundational observation of her religion research: belief in the supernatural is hard. This observation challenges the common assumption in anthropology that outside Western culture the supernatural is a common feature of everyday life. In fact, people of all cultures must go to great lengths to make the supernatural world appear real to them. More than this, the reality of the supernatural is often acknowledged to be qualitatively different from the reality of the material world. A spirit may be understood to be present and real in the middle of a complex and theatrical ritual but this presence quickly fades as the ritual ends – and if a ritual is neglected, the spirit becomes less real. Supernatural entities do not persist on their own but require regular ritual practice to sustain their reality. As an anthropologist, Luhrmann avoids making a metaphysical judgement here and later references Matthew Ratcliffe's Feelings of Being to explain the variable sense of reality that gods and spirits have for people. All of this occurs in what Luhrmann calls the faith frame, an ontological framework for an individual that carries a set of expectations about the appearance of the supernatural. It is maintaining the faith frame alongside material reality which is hard work for religious practitioners.

Chapter 2, ‘Making Paracosms’, introduces the concept of a paracosm, a private but shared social imaginary world (such as Tolkein's Middle Earth). Paracosms tend to be intricately detailed and this is what makes them feel real: one can return to a paracosm time and again to tell new stories and occupy alternative perspectives. Luhrmann's claim here is that religions create paracosms. The gospels, for example, invite the reader into a shared imaginative world where one can encounter Jesus. Religious paracosms are special because, through them, religious practitioners develop parasocial relationships with gods and spirits, imaginative relationships with invisible others who respond. Imagination does not, for Luhrmann, imply fiction – and Luhrmann remains staunchly agnostic when it comes to the veracity of religious experiences. Rather, the concept of imagination simply reflects the fact that any relationship with an invisible other must be qualitatively different from an ordinary relationship. Without input from sense experience, such relationships must rely on one's imaginative faculties, through which the supernatural other is encountered. Luhrmann does not offer a strict definition of imaginative faculties – they are not restricted just to mental imagery – but it is clear that their function is not limited to momentary experiences. People live large parts of their lives in paracosms, with a detailed understanding of how to engage meaningfully in them and what counts as interaction.

In chapter 3, ‘Talent and Training’, Luhrmann introduces two psychological skills which are related to the proclivity to experience gods and spirits: absorption and inner sense cultivation. Absorption describes the capacity for deep inner focus, to become deeply engrossed in something and lose one's sense of time. Inner sense cultivation is the deliberate and skilful use of inner visual representation through visualization techniques. Importantly for Luhrmann, these skills involve both an element of innate talent but also the capacity for anyone to train and develop them. Three findings from Luhrmann's research on witchcraft in the UK are indicative of this interplay between innatism and training for spiritual experiences more generally. These are: (a) to do magic, you must practise; (b) some are naturally more proficient than others; (c) anyone who practises will get better. Chapter 3 begins to reach the heart of Luhrmann's argument: that sensing the presence of gods or spirits is a measurable human ability; some are naturally better than others but anyone can improve through repeated practice. An important corollary of this is that the processes by which people experience gods and spirits are uniform across different religious traditions. Although the form of the training and the experience will alter across diverse cultures, Luhrmann observes that similar training techniques routinely produce similar results.

Having argued for the ubiquity of spiritual training practices in chapter 3, Luhrmann then analyses how different cultural perspectives on the mind influence how gods or spirits are experienced in chapter 4, ‘How the Mind Matters’. She does this through a comparative study of evangelical churches in the United States, India, and Ghana. Despite these three churches sharing both the expectation and the experience of hearing God's voice, cultural assumptions about the mind alter how God is heard in each context. To summarize a detailed study briefly, Luhrmann finds that evangelicals in the United States – an individualistic society which highly values private feeling – are more likely to hear God as an inner voice. Indian evangelicals, situated within a more other-oriented culture, tend to experience God through the actions or words of others. Ghana is different again, what Luhrmann calls a ‘soma-and-spirit-oriented’ culture (107); the Ghanaians she interviewed had an intense awareness of spiritual authority and power, and reported hearing God more affectively than linguistically. As important as the differences between these groups are the commonalities. Despite culture influencing how God is heard, evangelicals in all contexts had to work hard to sustain a sense of God's realness.

In chapter 5, ‘Evidence for the Way Gods and Spirits Respond’, Luhrmann turns to religious experience which, pace William James, exhibits genuine diversity across individuals and communities. Here Luhrmann introduces kindling, a biomedical concept which describes how an initial stimulation can predispose a body to a later stimulation. Luhrmann develops this into the idea of spiritual kindling, describing how an initial spiritual experience can predispose a body for a similar experience in the future. Luhrmann's argument here is that an individual's proclivity for any specific religious experience is a combination of their ‘bodily vulnerability’ (118) to the experience and cultural expectation. A useful heuristic arising out of this chapter is Luhrmann's categorization of religious experiences according to their physiological and phenomenological specificity. Interestingly, Luhrmann finds that this specificity inversely predicts the commonality of an experience, but that specific experiences which are culturally meaningful are reported at a higher frequency. This is important because the ability to kindle specific, culturally meaningful religious experience provides ‘firsthand evidence that the claims of the faith frame are valid’. God becomes real through ‘bodily evidences’ (135), which can be kindled through a combination of existing proclivity and cultural expectation.

Luhrmann confronts the topic of prayer in her sixth chapter, ‘Why Prayer Works’, specifically analysing how the practice of prayer can sustain a faith frame. We should, Luhrmann maintains, avoid talking about prayer solely or even primarily in terms of requests or transactions, arguing (in a Wittgensteinian move) that we cannot understand prayer if we think it is founded on a mistake. Prayer for Luhrmann is a metacognitive activity which allows people to engage in emotion management. Prayer changes people: through prayer, individuals develop an increased commitment to a faith frame and can view things from a new perspective. The prayer practices of gratitude, confession, and asking operate as ways of reframing and emotionally managing disappointment, guilt, and an uncertain future. As well as this (and distinguishing it from mindfulness techniques), prayer involves an imagined listener and so provides the therapeutic benefits of being heard. However, Luhrmann argues, prayer is not just therapeutic: rather, prayer kindles the experience of an invisible other, through which praying individuals can develop intimacy with a God who feels more real. This is reflected in the final aspect of praying Luhrmann discusses – adoration. Adoration is not a cognitive reframing but rather creates an attachment and a social relationship. Thus, Luhrmann argues that ‘prayer's most powerful and consequential feature’ (154) is its capacity to make God feel real and sustain a believer's relationship with an invisible other.

In the seventh and final chapter, ‘A God Who Responds’, Luhrmann concludes her study by asking ‘what happens when faith practices kindle a god or spirit into feeling real?’ Her answer: ‘gods and spirits respond’ (157). This is what distinguishes religious faith from play or pretend: the imagined gods or spirits are experienced as genuine others with the capacity to surprise and change those who relate with them. Again, it must be remembered that, when Luhrmann discusses religious or spiritual reality, she is operating with a methodological agnosticism. To say that gods and spirits respond does not entail a metaphysical claim that gods and spirits are real. What Luhrmann is interested in is the appearance of reality to religious practitioners, and Luhrmann would argue that, even if gods and spirits are real, they still must appear as real to individuals in order to make a difference. A sceptic might assume that people invent or project gods or spirits which suit and reflect their needs, yet this is not how faith is experienced. The invisible others kindled by religious activity are not predictable and can often be very demanding. Relationships – even with invisible others – can be beneficial for people but only, Luhrmann argues, if those others feel real. This is why the imaginative practices described in the book are so important. Kindling the presence of invisible others makes those invisible others feel real and thus enables the formation of genuine relationships. Luhrmann thus concludes her study with a call for anthropology of religion to shift its focus from beliefs to relationships. The fundamental anthropological question should not be just to understand why people believe what they do, but to understand ‘that when gods and spirits feel real to people, they have become beings that humans can love, argue with, and wrestle against’ (184).

Although it is written as a work of anthropology, How God Becomes Real is philosophically informed and should stimulate debate in philosophy of religion. Luhrmann's conceptualization of religious experience as a skill, innate but trainable, offers an important new angle on classic debates about religious experience. Her approach walks the line between, on the one hand, accepting wholesale the claims of religious practitioners and, on the other, dismissing religious experiences as hallucination or wish fulfilment. Nevertheless, the theist may remain doubtful about this approach. Luhrmann intentionally avoids suggesting that her research explains away religion, yet she does admit her own scepticism of theistic belief towards the end of the book. Hence, despite her intimations to the contrary, the depth of Luhrmann's psychological explanations might appear to some to rob religion of its mystery and undermine the divine initiative. Such an evaluation is not mandated by this work, however. Luhrmann summarizes her approach to theology in her previous work, When God Talks Back (2006): ‘I will not judge whether God is or is not present to the people I came to know. Yet I believe that if God speaks, God's voice is heard through human minds constrained by biology and shaped by their social community’ (xxiv). Humanizing the study of religion can broaden philosophical debates around these topics and Luhrmann's work can perhaps help to break down a dichotomy of fideistic and dismissive responses to religious experiences.

More broadly, Luhrmann's call to shift the focus of anthropology of religion from beliefs to relationships is one which deserves to be heard in philosophy of religion too. Recent work on lived religion in philosophy of religion has begun to make moves in this direction; How God Becomes Real offers valuable material – in the form of both ethnographic detail and conceptual analysis – for philosophers involved or interested in this development. Philosophy of religion benefits when philosophers seek to understand the reality of how religion is experienced by its adherents across the world; to this end, How God Becomes Real is an excellent resource for philosophers of religion.