In the last 15 years, there has been a rapid increase in the number of people who identify as having no religion. In many countries where Christianity has traditionally made up the religious majority, nonreligious populations are now significant. For instance, nearly one quarter of the populations of Canada and the US identify as nonreligious, along with one fifth of Nordic people (that is, people in Sweden, Norway, Denmark, and Finland). Britain’s nonreligious population has almost surpassed the religious. Over 30% of Australians identify as nonreligious, and Latin America’s nonreligious population varies from 8% to 37%. In all these countries, younger people are even more likely to identify as nonreligious, suggesting that the percentage of people identifying as nonreligious will continue to grow. This shift is profound, and its social impact is increasingly evident in public spaces where nonreligion challenges taken-for-granted religious practices, such as in schools, hospitals, and courts of law. As factors like conflict-driven migration cause societies to become increasingly diverse, the impact of nonreligion will only become more pronounced.

Despite this phenomenon, nonreligion is often absent in discussions about living well together in diversity, which often focuses only on religious diversity. This is partly due to the shortage of data on what constitutes nonreligion, and how nonreligion is framed in societies. Current social scientific methods have not captured the rapidly changing nature of both nonreligion and religion in their many forms or the grey areas between them. Many approaches equate nonreligion with atheism or reduce it to ‘the secular’, which limits nonreligion to only a small part of the phenomenon this project is investigating. More than atheism, nonreligion includes agnosticism, humanism, spiritual but not religious, indifference, and other varieties of nonbelief. More than just ‘the secular’, there are many ways to understand nonreligion and its links to concepts such as nationhood, democracy, secularism, laïcité, values, morality, culture, and heritage. It is through this wide lens that we can begin to better understand the shape of nonreligion, observe how nonreligion and religion are negotiated in society, and develop evidence-based constructive policies to address the tensions that arise from those negotiations.