I normally don’t enjoy Quora. But I was just asked an anonymous question there which made me react. It’s close to the kind of question I get in my intro-level courses in sociology or anthropology, so I like to “do my job” of elucidating these issues.

Here’s the question:

Can there be such a thing as too much diversity?
Up until recently the rule for all immigrants was “When in Rome do as the Romans do.” This appears to have been replaced by “We’re not going to integrate but live as we did back home.”

Is it possible that at some point diversity becomes a detriment that divides society? Just look at how segregated some cities have become

Here’s my answer:

Funnily enough, I’m preparing an exam on material where this very issue appears. Unfortunately, this material isn’t online.
One of sociology’s core perspectives, functionalism, had “extreme diversity” among the conditions under which social order breaks down. The idea, there, was that it went against society’s integration, since the model was based on well-delimited groups.
That theory has been challenged multiple times. For one thing, very few groups have been that well-integrated. The modern notion of “what The Romans were” comes from a biased view and a limited understanding of what went on at the time. In fact, an episode of the Entitled Opinions podcast contains useful discussions of the very issue.

Same thing can be said about a number of other societies, including contemporary ones.
And this is where things get interesting. We’re probably living a transition from a period marked by the Nation-State (19th and 20th Centuries) to a period marked by fluid groupings, including social networks.
In the Nation-State (contemporary Somalia and Japan, along with the fiction of 19th Century France and possibly a short period of time in Ancient Rome), ethnic homogeneity is presumed and ethnicity is managed through a very complex bureaucratic system related to citizenship. The way ethnic groups are treated then is based on what Benedict Anderson called “Imagined Communities”.
In more fluid systems, which include most of human history, diversity is taken for granted and social integration comes from other dimensions of social life.
In the current context, we have an unusual mixture of rigid Nation-State identities in parallel with the reality of transnationalism, postnationalism, Globalization, and blurred boundaries.
So, to answer the question: is it so clear what the limits of the group are? If so, what are those limits based on? If not, why would diversity be a problem?

For those interested in fluid boundaries, a classic work is Norwegian anthropologist Fredrik Barth’s “Ethnic Groups and Boundaries”.