What is religion? How scholars define it, and why it's hard

Religion is a shared system of beliefs, practices and communities that orients people toward what they hold sacred or ultimate: gods or spirits, a moral order, a path to liberation, or the meaning of life and death. That much most scholars accept. What is religion beyond that is argued, because no single definition fits every tradition people call one, and each definition draws the line in a different place.

In short

• Most definitions combine three things: belief in something beyond ordinary experience, practice such as ritual and ethics, and belonging to a community.
• The best-known scholarly definitions, from Tylor, Durkheim and Geertz, each include and exclude different cases, such as Buddhism or a political ideology.
• In 2020, about three in four people in the world identified with a religion, according to the Pew Research Center; about one in four did not.

Where does the word religion come from?

The English word comes from the Latin religio, which meant something like scrupulous care, a felt obligation toward the gods, rites and taboos. Ancient writers disagreed about its root. Cicero linked it to relegere, to go over again carefully, as in repeating rites; the Christian writer Lactantius, to religare, to bind, as in binding people to God. The modern sense, "a religion" as one of several comparable systems, each with its own beliefs, came much later, in early modern Europe, as Christians met other traditions and began comparing them.

That history matters. Many languages had no exact word for "religion" until the 19th century, because what Europeans meant by it was not a separate part of life there. Sanskrit's dharma, for example, covers duty, law, cosmic order and right practice at once. So when scholars ask what religion is, they are partly asking whether a concept shaped in one culture can describe all the others. The strongest reply is that the word may be European while the things it groups, gods and spirits, rites, sacred texts and communities of practice, are found almost everywhere, so the concept can be used with care, as "art" or "politics" are.

How do scholars define religion?

Three definitions shaped how the field thinks, and each is still quoted because it captures something the others miss.

Edward Burnett Tylor, an English anthropologist, proposed in Primitive Culture (1871) a "minimum definition": religion is "the belief in Spiritual Beings". It is a substantive definition, one that picks out religion by what it believes in.

Émile Durkheim, the French sociologist, rejected that approach in The Elementary Forms of the Religious Life (1912). He defined a religion as "a unified system of beliefs and practices relative to sacred things, that is to say, things set apart and forbidden", which "unite into one single moral community called a Church, all those who adhere to them." It is a functional definition: religion is what binds a group around what it treats as sacred.

Clifford Geertz, an American anthropologist, wrote in 1966 that religion is "a system of symbols which acts to establish powerful, pervasive, and long-lasting moods and motivations" in people "by formulating conceptions of a general order of existence" and clothing them with such an aura of factuality that the moods and motivations "seem uniquely realistic". For Geertz, a religion offers a picture of how the world ultimately is, and makes people feel and act in line with it.

What does each definition leave in or out?

The real test of a definition is the hard case. Run five of them through the three:

Case	Tylor: belief in spiritual beings	Durkheim: sacred things and a moral community	Geertz: symbols, moods and a general order of existence
Christianity, Islam, Hinduism	In	In	In
Theravada Buddhism, whose teachings require no creator god	Doubtful for the doctrine; in for the gods and spirits many Buddhists honor	In: the monastic community, relics and the Buddha's teaching are set apart	In
Confucianism, centered on ritual, ethics and ancestors	Partly: ancestors are honored, but the core is ethical	Arguably in	Arguably in
A football club's devoted fans	Out	Arguably in: sacred objects, rituals, a community	Out: no picture of the order of existence
Soviet [[what-is-communism	Marxism-Leninism]]	Out	Arguably in: sacred texts, rituals, a moral community

Tylor's definition draws the line too tight, and Durkheim's can draw it too loose. Durkheim himself pointed to Buddhism as proof that gods were not essential. Critics of functional definitions reply that if a football club counts, the word has stopped meaning anything. Geertz sits between them, but his focus on inner meaning was itself criticized, notably by the anthropologist Talal Asad, as reflecting a Protestant Christian idea that religion is mainly a matter of private belief rather than practice and authority, as the Stanford Encyclopedia of Philosophy's entry explains.

Many scholars now use a "family resemblance" approach, borrowed from the philosopher Ludwig Wittgenstein: there is no single feature every religion has, but religions share overlapping ones, such as gods or spirits, sacred texts, ritual, moral codes, a community, a story about where the world came from, and a hope beyond death. A tradition counts if it has enough of them. This fits the evidence better, at the price of fuzzy edges, which is where the interesting cases live.

What are the world's largest religious groups?

The Pew Research Center's estimates for 2020, published in June 2025, are the most widely cited:

Group	Began	Main scriptures or texts	People in 2020	Share
[[what-is-christianity	Christianity]]	1st century CE, Roman Judea	The Bible	2.3 billion
[[what-is-islam	Islam]]	7th century CE, Arabia	The Qur'an; the hadith	About 2.0 billion
Religiously unaffiliated	—	—	1.9 billion	24.2%
[[what-is-hinduism	Hinduism]]	Roots in Vedic religion, from about 1500 BCE, South Asia	The Vedas, the Upanishads, the epics, the Bhagavad Gita	1.2 billion
[[what-is-buddhism	Buddhism]]	About the 5th century BCE, northern India	The Pali Canon; the Mahayana sutras	324 million
[[what-is-judaism	Judaism]]	Ancient Israel, first millennium BCE, with older roots	The Hebrew Bible; the Talmud	14.8 million
Other religions	Many origins	Many	—	2.2%

"Other religions" includes Sikhism, Jainism, Baha'i, Shinto, Taoism, Chinese and African folk religions and many more, which Pew groups together because each is small or hard to measure separately.

How are religious people counted, and how sure are the numbers?

Pew built its figures from more than 2,700 sources, mostly national censuses and large surveys, covering 201 countries and territories. They count identity: what people say they are when asked. That choice shapes the result in three ways.

First, the unaffiliated are not all atheists. Pew notes that many people who claim no religion still believe in God or spirits, or pray. Second, questions differ between countries, and some countries don't ask at all. China, with about a sixth of the world's population, decides much of the global total: under the Chinese survey measure Pew used, only about 10% of Chinese adults claim a religious identity, even though far more take part in practices such as honoring ancestors at their graves. Count those practices and the world looks more religious. Third, belonging, believing and practicing can come apart: a person may identify as Jewish or Christian by heritage without believing, or practice Buddhist meditation without identifying as a Buddhist.

So the figures answer one question well, how people describe themselves, and others less well. They are estimates, not a census of belief.

Why does the definition matter?

The definition has real effects. Laws on religious freedom, tax exemption and religious discrimination need some idea of what counts. Courts have had to decide, for instance, whether a sincerely held ethical belief with no god qualifies for a religious exemption. And how religion is defined decides what the study of religion studies, a question that connects it to philosophy, anthropology and history.

Check yourself

• Without looking back: give Tylor's definition and Durkheim's, and name one tradition each would struggle with.
• Why do some scholars say the very idea of "a religion" is a European invention, and what is the strongest reply?
• Why are the "religiously unaffiliated" not the same as atheists?

Sources

• The Concept of Religion — Kevin Schilbrack, Stanford Encyclopedia of Philosophy, 2022
• How the Global Religious Landscape Changed From 2010 to 2020 — Pew Research Center, 2025
• The Elementary Forms of the Religious Life — Émile Durkheim, translated by Joseph Ward Swain, Project Gutenberg
• Definition of religion — Wikipedia
• Religion — Wikipedia