Religion is the belief in supernatural forces that can act on the world and influence human lives. Most of the 6.2 billion people on this planet would consider themselves religious, although they might differ widely in what specific religion or traditions they belong to. The vast majority of these traditions are “monotheistic,” believing in a single god. Others are “polytheistic,” believing in multiple gods. Yet despite these differences, religions have universal appeal and can be found in all cultures.

Why religion is so widespread is a question that has stimulated much scholarly debate. One approach focuses on the idea that religion evolved to serve as the foundation for large, cooperative societies. A second view argues that it serves to provide a framework of values and a set of behavioral norms for human conduct. These functions are likely to explain its broad-based popularity and cross-cultural ubiquity.

Whether they are organized as churches, mosques, synagogues or temples, most religions have a number of core features. They include a group of believers, beliefs in the afterlife, and practices such as worship and prayer. They also tend to have a moral code, a system of rituals, and an authoritative figure or leaders. Some religions even have institutions such as schools, hospitals and charitable organizations.

All of this is meant to reassure and comfort believers in the face of death and life’s uncertainties. This can be an important factor in the positive health benefits of religion that have been shown by many studies, including lower rates of depression and a greater likelihood to attend church services, practice good health habits such as exercise and abstain from smoking or drug abuse.

In addition, most religions teach that humans should treat their fellows fairly and help the needy. Such teachings can reduce the stress of dealing with life’s difficulties and can foster a sense of responsibility for other people, boosting levels of community involvement.

But perhaps the most basic reason that religion is so pervasive has to do with human nature. Most people see their lives as a project in which they are constantly evaluating their actions, trying to be wise or fair and acting with the well-being of other people in mind. Humans know that they live in a world with an acknowledged but largely unknown future, so evaluating their actions is built into the human psyche.

Religions are a natural outlet for these human needs, offering a set of tools and methods for dealing with the uncertainties of life and the pains of living in a fallen and flawed world. These benefits, along with the fact that religions can be trusted to protect their followers, are what make them so appealing. Totally secular approaches to public policy, psychotherapy and education are a mistake. These efforts ignore the fact that, for two-thirds of the world’s population, religious beliefs are a powerful and useful part of their lives. This is a truth that should be reflected in our policies and our discussions of them.