I’m always a bit surprised at the number of people I meet who don’t realize that kinship systems are cultural constructs. There is a biological connection, of course, but order is imposed by systems that vary across cultures.
In some cultures, cousins of a certain type are assimilated into the same kinship class as brothers and sisters. In other cultures, a person might belong exclusively to the family of the father or the mother, while the other parent is only a relative by marriage. I imagine most of us have some idea of the astounding number of variations from what we remember of Anthropology 101.
If we’re not careful, we might think about these other systems and feel just a bit superior because we use don’t have any such quaint ideas. Our system is an irreducible universal, based on biology. Whatever other systems our ancestors might have used have been eroded away. We now use a simple system that divides relatives into the two categories of relatives by blood (consanguinal) and relatives by marriage (affinal). We calculate kinship bilaterally, taking paternal and maternal relatives equally into account, but use an elaborated system to weigh the distance of a biological relationship (1st cousins, 2nd cousins, and so on).
Forget all that.
The reality might come as a surprise to amateur anthropologists who are used to picking up second-hand reprints of 19th century texts at the local used book store. In fact, there is no evidence that the cultures who use all those quaint systems are any less sophisticated than we are when it comes to envisioning biological relationships. The difference between us and them, is that they have elaborated cultural systems overlaying biology, and those systems play significant roles in their culture.
Moreover, despite the erosion of our older Germanic kinship systems, we do have one vestigal survival of a cultural system — the surname. Each of us officially belongs to one, and only one, family. Our family name is our badge of membership in that lineage group. It’s not a coincidence that the surname is often called the family name. (Of course, since we use a bilateral kinship system, we end up with culturally significant relatives in other families.)
An easy way to see this point is to think about the inheritance of surnames. We all have eight great grandparents. All of them are equally our ancestors, but we inherit a surname from only one of them. There’s no biological reason to privilege one line of ancestry; it’s merely a cultural artefact. Such cultural systems always interact with other parts of a culture, however trivially. In our culture, some preference rule is arguably necessary if we are to have use surnames at all. It would become very cumbersome to use the surnames of all your ancestors, or even of your eight great grandparents — I would hate to go through life as Justin Howery-Alloway-Horn-Quillen- Swanstrom-Fyrsten-Luce-Wilson!
The residual significance of surnames becomes clearer when we look at our European cousins. In America, changing your surname is a relatively simple matter of appearing before a judge and making a case that there is nothing improper about the change. But, in some European countries it is illegal to adopt a surname that did not belong to one of your great grandparents. And, in Iceland, it is illegal to adopt an hereditary surname.
Although I’m primarily interested in surnames, it’s interesting to note that our supposedly logical kinship system does become a bit untidy at the edges, particularly when it comes to adoptions, relationships by marriage and relatives we don’t know. There is an interesting book, David M. Schneider, American kinship: a cultural account (University of Chicago Press, rev. 1980) that reports the results of a study of American kinship patterns. According to author, Americans become confused when asked about the cultural component of kinship. For example, is a woman your aunt if she is your uncle’s wife but you’ve never met her? Is she still your aunt if your uncle divorces her? If they get a divorce, does it make a difference if she is the mother of your cousins? Does it make a difference if she was your aunt when you were a child, or if she is someone your uncle married late in life? Is your sister’s husband’s sister your sister-in-law? Is her husband your brother-in-law? Where do you draw the line? What about a half-sibling that you’ve never met? Does it make a difference if the half-sibling is a child your mother gave up for adoption, or the by-blow of your father from a one night stand? What about the adopted child of a cousin? The collective answers to such questions show that, as a whole, Americans use a complicated and highly subjective system of biology, marriage, fosterage, adoption and acquaintance to define kinship, while stubbornly insisting that they are using only biology and marriage.