In recent decades, scientific efforts to probe religious behavior and mental states have increased markedly in quantity and sophistication, yet the fascinating story of the psychology of religion remains unfamiliar not only to the general public, but also to many social scientists. This chapter starts with case studies of how religion has functioned in several prominent human lives. We consider why the psychology of religion matters and delve deeply into the many problems associated with defining religion, spirituality and the psychology of religion. The psychology of religion probes religious beliefs, attitudes, behaviors, emotions, experiences, and relationships, paying particular attention to the consequences of religion for health, well-being, morality and social relations. Scholars debate: (1) the importance of the field’s history and grand theories, (2) the acceptability of the historical emphasis on Western Christianity, (3) the generalizability of much empirical work, (4) the meaning of spirituality outside of religion, and (5) whether the discipline is biased in favor of or against religion.

It is suggested that current religious studies are distorted by what sociologists sometimes call recipe knowledge, especially in relation to the common assumption – still partially valid – that religion should no longer be seen in essentialist or perennialist terms. The possibility of neo-perennialism is explored. Widespread assumptions about projecting onto faith traditions ‘essentialist’ understandings are critiqued, particularly in relation to Buddhism, and common assumptions about the inapplicability of terms such as religion and myth are questioned. In this context, evolutionary perspectives are important because ‘dual process’ notions of human cognition may be applied to the historical development of human religiosity. This means that a revived recognition of a universal aspect of human religiosity is necessary, based not on very questionable anthropological speculations of the kind that became common in the late-nineteenth and early-twentieth centuries but on current exploration of brain functioning and of its evolutionary development.

This chapter considers the implications of this study for the broader history of medieval Sunnism and comparative work on heresy and orthodoxy in the field of religious studies and history. It concludes that proto-Sunni orthodoxy was an evolving process. Not only did it undergo a number of iterations, but it was characterised by internal contradictions and divisions. The failures of proto-Sunnism were as relevant to the formation of medieval Sunnism as were its successes. Medieval Sunnism was a product of constant tensions. These required negotiations. In order to appreciate the historical achievement of classical Sunnism, examining its most contentious times is integral to making sense of its most agreeable times. In this sense, to study the formation of orthodoxy and heresy in medieval Islam is to come to terms with a truism that ‘traditions, when vital, embody continuities of conflict’.

Ethical quandaries – such as justice and equity for under-represented communities, treatment of animals in laboratory and field research, and editing the genomes of plants, animals, and humans – are becoming ever more insistent in socio-environmental research. Accordingly, socio-environmental research requires that natural and social scientists become conversant with the humanities and that humanists actively engage, in accessible terms, the conceptual and ethical concerns arising in the sciences. Research methods in the humanities differ – where scholars begin with a thesis instead of a hypothesis – from those in the natural and social sciences. While the methodological differences between research in the humanities and the sciences render interdisciplinary cooperation and even communication between these two broad types of inquiry difficult, this section draws attention to the important contributions that ethical, religous, and historical approaches have made to understanding the reciprocal relationships between society and environment. These contributions range from scholars such as Aldo Leopold, Lynn White, and William Cronon to Vandana Shiva, Leonardo Boff, and Gregory Cajete.

The classical definition of theology reflects fides quaerens intellectum (faith seeking understanding). This definition underscores the premier role of faith, reason, and critical thinking in the exercise of theological studies. Religious studies for its part is a social science study of religion, which also applies critical thinking and reason in its research, but does not necessarily require faith. Therefore, both theology and religious studies have thrived by the application of the tools for critical thinking and reason. For undergraduate research in theology or religious studies, the methodological approach of students depends on the focus of the course. The different sub-disciplines of theology or religious studies adopt different approaches to research. Therefore, a course on the history of the Bible would require different research method and approach than a course about social justice or comparative religion. However, regardless of the course, it is important to always bear in mind that a typical piece of research on religious studies or theology will likely adopt diverse research approaches and methods.

Chapter 1 discusses how the categories of analysis traditionally used by scholars of the New Testament and early Christianity can be refined, with critical attention paid to terminology, vocabulary, and anachronism. Invoking the work of J. Z. Smith, Stanley Stowers, Eric Hobsbawm, and others, this chapter challenges how Christianity was rhetorically “invented” after the first century and how a figure like Paul the Apostle was transformed into one of the founders of Christianity, despite questions about how effective his so-called ministry was at creating cohesion about presumed Christian “communities.”

The Introduction outlines the primary theoretical approaches of the monograph and scrutinizes why the study of early Christianity and the New Testament tends to adopt idiosyncratic methodologies when compared with allied fields like classics. Chapter summaries are provided as well as a discussion of what I term the “paradigm of exceptionalism,” or the reasons why so-called religious literature – that is, writings associated with still-practiced religions – often faces a different set of evaluative criteria within the academy.