Religion is a cultural system of behaviors, beliefs and ethics that define what people hold sacred or spiritually significant. It also provides a framework for understanding the universe and a means to cope with human life. Religious stories, symbols and practices can also create a sense of community among like-minded people. This sense of social belonging may partially explain why religions are so durable and widespread across the globe.
Historically, the concept of religion has been defined in many different ways. Some approaches have been narrow in their focus, while others have been more broad based. Narrow definitions have been used to facilitate comparative studies of religion, and to make it easier to identify common elements in various religious traditions. However, such a narrow approach can have the disadvantage of neglecting important differences between religions.
A broader approach to the study of religion has been facilitated by the development of science and technology. In particular, advances in genetics have given rise to the discipline of evolutionary psychology, which uses natural selection theory and empirical data to study how religion and other psychological traits develop.
In addition, the growth of tourism has introduced Europeans to a great diversity of cultures and their religions. This has stimulated the study of comparative religion. For example, Edward Burnett Tylor (1871-1930) developed a classification of religions based on the belief in spiritual beings, and the development of more or less systematic compilations of mythological material.
One of the problems with defining religion is that it has to do with so many things. There are countless different religions, and they all differ from each other in many ways. It is therefore difficult to establish a clear, consistent set of criteria that would allow researchers to categorize them all as the same thing. A strict definition of religion is also problematic because it excludes those who do not believe in a particular god or spirit.
For these reasons, scholars often use a polythetic approach to the study of religion. This allows for multiple interpretations of the same basic characteristics, so that a wide range of explanations can be considered. In this way, the study of religion is more likely to be objective and useful.
The idea that religion is a universal phenomenon has led to many theories about its origins and functions. Some of these have a naturalistic focus, such as the scheme worked out by Giambattista Vico (1668-1744) that argues that Greek religion developed in stages. Other theories, particularly those of German philosopher Emile Durkheim (1818-1883), are based on the idea that religion is a social phenomenon that arises out of the need for a communal identity in modern industrialized societies.
Research has shown that people who are religious tend to enjoy healthier and happier lives. For example, they are less prone to depression and more likely to visit the dentist. However, it is not clear why this should be the case. Perhaps the most convincing explanation has to do with the fact that religions act as early and successful protective systems.