Most animals are born knowing much of what they need to survive. Humans are born with a capacity to learn, and then must learn almost everything else from the people around them. That learned inheritance is what anthropologists call culture, and it is the central idea of the discipline.

What culture is

The first widely used definition came from the English anthropologist Edward Burnett Tylor in Primitive Culture (1871): "Culture or Civilization, taken in its wide ethnographic sense, is that complex whole which includes knowledge, belief, art, morals, law, custom, and any other capabilities and habits acquired by man as a member of society." The key word is acquired. In Tylor's definition, culture is what a person acquires as a member of society, not what they inherit through their genes. A baby born in Tokyo and raised in Nairobi will speak, eat and joke like a Nairobi child. Learning one's own culture while growing up is called enculturation.

Anthropologists add several features to Tylor's list. Culture is shared, though never perfectly: within any society people disagree, rebel and invent. Culture is symbolic, built on meanings that are agreed upon rather than natural. Nothing in the color white means mourning or purity, and different societies have read it both ways. Culture is integrated, which returns us to holism: its parts fit together, so a change in one tends to ripple through the others. And culture is always changing, through invention and through diffusion, the spread of ideas and practices from one society to another. Chili peppers, now central to cooking in India, Thailand and Korea, came from the Americas and spread across Asia only after 1492.

Boas and the end of the ladder

Tylor and many of his contemporaries also believed in what is now called unilineal evolution: the idea that all societies climb the same ladder of stages from "savagery" to "civilization", with Victorian Europe near the top. The American lawyer and ethnologist Lewis Henry Morgan set out such stages in Ancient Society (1877). The scheme flattered Europeans and was used to justify colonial rule over peoples labeled as lower on the ladder.

Franz Boas attacked this view. He argued that each society has its own history, shaped by its environment, its contacts with neighbors and its own inventions. The approach became known as historical particularism: each society must be understood through its own particular history, not ranked on a single scale. Boas also tested the claim that racial types were fixed. In a study published in 1911, Boas found that head shape differed between immigrant parents and their American-born children, a sign that even a trait once treated as a racial marker responded to environment. The study has been reanalyzed and debated since, but his broader point, that culture rather than race explains most differences in behavior between groups, became a pillar of modern anthropology.

Two kinds of relativism

From Boas came cultural relativism: understand a practice in its own context before judging it. Anthropologists distinguish two versions. Methodological relativism is a research tool: suspending judgment long enough to understand. Moral relativism is a much stronger claim: that no practice can be judged right or wrong except by the standards of the culture that holds it.

The difference matters. In 1947, as the United Nations drafted the Universal Declaration of Human Rights, the American Anthropological Association's Executive Board warned that a universal declaration might impose Western values on other peoples. The statement, drafted largely by Melville Herskovits, came from a real worry about colonial arrogance. But it was soon criticized, including by anthropologists, for seeming to leave no ground from which to condemn oppression carried out in the name of tradition. Over the following decades the discipline changed course. In 1999 the AAA adopted a Declaration on Anthropology and Human Rights committing the association to human rights, while urging that they be understood broadly enough to include collective and cultural rights.

The limits

Defenders of a careful relativism point out that cultures are not single voices. Inside every society people argue about their own customs, and the strongest critics of a harmful practice are often members of that society. Respecting a culture does not mean siding with its most powerful members against its weakest. Critics of strong relativism add a sharper point: if right and wrong were only whatever a culture approves, then reformers who opposed their own majority, from abolitionists to the Chinese campaigners against foot binding, could never have been right. Most anthropologists today hold two ideas at once: understand first, and still defend the dignity of every person.

Worked example: a disputed custom

A researcher studies a rural district where some families arrange marriages for daughters as young as fourteen. Using methodological relativism, she sets aside her shock and learns why: scarce land, alliances between families, fear of poverty and ideas about family honor. She records the views of fathers, mothers, elders and the girls themselves, and finds that many young women and several local teachers oppose the practice. Her understanding lets her explain the custom fairly. It does not oblige her to call it right. Her report describes the reasons behind the practice and the harm it does to girls' health and schooling, and it gives space to the local voices already working to change it.