Religion is a phenomenon that arises from the need of humans to have faith and meaning and value, and to share this valuation and at times to sacrifice for it. It is also the primary system through which this valuation is expressed and transmitted from one person to another, and it has been shown to act as a cohesive force that has helped bind societies together.
The word “religion” comes from religio, a Latin term that approximates to scrupulousness. Early on, it was probably a label applied to people who kept their promises, taboos and curses (or at least the most egregious violations of them). Later, with the advent of a variety of different gods, the word came to be used to describe a particular way of worshipping or expressing devotion. The resulting concept of religion is, therefore, very broad. It includes not only beliefs about disembodied spirits and cosmological orders, but also a huge range of practices that can be described as religious, such as adoration, generosity, ecstasy, prayer, sacrifice, puritanical self-denial, superstition, piety and so on.
These are, of course, not the only things that human beings value and that they express in a variety of ways, but they are among the most important and most distinctive. That is why most of us, at some point in our lives, will find ourselves drawn to join a religious community or to become attracted by the idea of joining a religion.
A religion provides a framework of sanctions and rewards, approval and disapproval, inspiration and ideation within which people can explore the ultimate questions of life: why did this happen and what does it mean? A religion also explains the universe and the place of mankind within it, and many religions claim to offer ways for people to experience or even live in a better future.
Lastly, a religion offers a way to understand and evaluate the world and other people in general, to help make wise and moral decisions in a complex and changing world. It is no surprise that it has been a source of such things as intolerance, cruelty, bigotry, social oppression and ruthless power-seeking, but it can also be seen as the heart and soul of what might otherwise be a heartless world.
The enormous variety of practices that can be labelled as religious is an intriguing challenge to the philosophy of religion, and it has been tempting to sort them into categories or groups on the basis of their various characteristics. However, this approach has its problems, and a much more promising line of inquiry is to treat the notion of religion as a family resemblance concept rather than as something that must have certain necessary and sufficient properties. This means that, as with the concept of literature or democracy, there are many different practices that can be called religious and many that cannot.