This post deals with common culture-based arguments people use to defend the "we need to close our borders for immigration"-position. Much of the anxiety involved here, I believe, stems from a lack of understanding for how cultures work. That has been explored in-depth in both sociology and anthropology, but the findings have apparently not been disseminated successfully.
Culture arguments"Refugees/immigrants are too different from 'our own' people, if they get to enter the country, our society will suffer from this difference."
First of all, research shows that migrants, regardless of "cultural distance" (whatever that means) can settle just fine in the host society. A conservative think tank has published the "assimilation index" (which seems to be really about integration, not assimilation) showing that migrants from countries like Vietnam and the Philippines do very well in terms of labour force participation, income levels and military service. This has not gone down with increased immigration, but rather the opposite. There is also this report that says roughly the same thing.
Second, the argument assumes that difference is bad. It thus builds on a long tradition of "us vs. them" that has been fueled by the idea that the "nation has to be ethnically homogeneous". That idea is a relatively recent one, emerging primarily in the 1800s. It argues that the state should be the vehicle for the self-determination of "the nation", and thus that borders should be created between nations, so that each nation gets its own state. See here an overview of nationalism as an ideology:
The problem is that nationalism idealizes the "magic line in the dirt", i.e. border-making. In reality, it's impossible to draw borders that creates homogeneous nation-states. Attempts to do so have led to disaster (see the ethnic cleansing during the wars after the collapse of Yugoslavia).
Also, a culture does not stop where the line on the map is drawn. I used to do an exercise where I challenged my students to name a country that was ethnically homogeneous. Just about any country that people usually think of as nation-states actually have a demographic reality that conflicts with the image of the ethnically homogeneous nation. A contemporary case in point is France, framed as a nation-state (some might say the original nation-state). Historically, the nation-state project was strong there, with heavy centralization from Paris. Just recently, the people in the Catalan region in Spain voted for separatist parties. Notably, the region with Catalan culture extends into France, but the way the borders have been drawn, the nationalist would expect that the Catalans of Southern France have more culturally in common with the Alsatians in Eastern France than they do with the Catalans in Northern Spain.
Japan also comes up often in this context, as it is a country many perceive as homogeneous, mostly because the Japanese government maintains this image to avoid acknowledging the ethnic minorities that do exist in the country. These include indigenous peoples in both the north and on Okinawa, as well as guest workers from China, Korea and the Philippines. Notably, the country's very restrictive border policies continues to block its economic development - the demographic challenge of an aging population that confronts all rich countries is most severe here, and as a consequence it experiences significant labour shortages. That could be solved if it opened up the borders to more immigration. So far, Japanese governments have refused, because of the strong pressure in the political culture to maintain the myth of nation-state homogeneity. Thus, the problem persists.
The most recent incarnation of the idea that difference is bad is Huntington's "Clash of Civilizations", which argues that the defining conflict in the post-Cold War era will be one between Western and other civilizations, particularly the Muslim world. This theoretical framework has been thoroughly picked apart. I even used to pick it apart together with my students to demonstrate the inconsistencies in Huntington's conceptualization of "civilization", but that's a subject for a blog post on its own. Suffice to say is that many politicians and pundits seem to have found Huntington to be deeply inspirational and keep using "Clash of Civilization"-style framing to argue that some cultures are "incompatible with others" and use that as a rationale to close borders.
Conflicts, instead, flare up when ethnic difference are politicized. That has happened in many places in the past, but in that case, bigotry is to blame, not ethnic difference in itself. Consider the Chinese, Korean or Japanese communities in the US. I would say that racism from the mainstream population have been a bigger barrier in their settlement than their "cultural difference". Conflict on a societal scale only tends to emerge when political leaders work hard to make them happen by blaming an ethnic group for things that go wrong in society (i.e. scapegoating). We could see that in Rwanda, in Yugoslavia, and so on. In that sense, it's a self-fulfilling prophecy, difference will lead to conflict when someone makes it a problem.
This argument is closely related to the previous one, but focuses more on the maintenance of "us as similar" rather than on "them as different". It is based on the idea that sameness is inherently good, which can be contested. Also, it assumes that culture is something static, and that it has always been there and somehow was more "pure" in the olden days, before we "mixed with others". This view is called primordealism and has problems. The idea that culture was "pure" once assumes that people didn't mix back in the day, but they did. People have always moved and cultures have always changed over time. This is most easily identifiable in how languages change: English today is not what it was 1 000 years ago, or 500 years ago or even a century ago.
Those governments that tried to stop cultural change have done poorly. Governments in both Imperial China and Japan tried to isolate those countries from the rest of the world precisely based on this idea - both felt that their own cultures were superior to all other cultures in the world. China implemented that policy in the early 1400s, at a time when China was the global superpower in just about every sense of the word - culturally, economically, technologically, militarily. 400 years later, the Chinese government discovered the consequences of the policy the hard way when it found how the Western European countries had passed it by entirely. Loss of innovation is the price of isolation. The Chinese population has paid a high price for that policy over the last couple of centuries and are only now, when the Chinese government has opened up the Chinese economy, starting to recover from it.
To take an opposite example, the United States accepted many migrants from diverse countries in the late 19th century. That did not destroy American culture, but rather contributed to the country's economic and cultural success in the 20th century.
Such examples call to mind research on group-think done on organizations. Such studies show how organizations that are too internally homogeneous lose the capacity to innovate, because there are too few perspectives, too few ways to challenging what is taken for granted. I don't think such experiences should be dismissed in this context.
Interestingly, when this "preserving our values"-argument comes up, it proves very difficult for its advocates to present a comprehensive overview of what those values are. Now, this is not to argue that ethnic identities do not exist, they do. A Swedish person does not have the same outlook on the world as someone from China or Brazil. Rather, cultures are diffuse, and also internally heterogeneous, and thus they resist attempts at codifying them for the purposes of legislation. For example, when the government of the UK tried to put together a document intended to demonstrate "British values"for immigrants, it ended up turning to the European Charter of Humans Rights. The European Charter of Human Rights is, of course, European, not specifically British. Also, Human Rights are not even specifically European, but much more universal. That's how it usually goes - the document becomes something very vague along the lines of democracy and human rights are important. They are, but they are not values that are unique for any particular nation-state, but rather shared by people globally.
"Their culture is primitive/backwards/heathen"
This is another argument inspired by a Huntingtonian worldview. Instead of saying "difference is bad" or "sameness is good", it says "we are better than those people in particular", which is a classic driver behind the racialization of ethnic groups. Notably, the hierarchy still is colour-coded. On top can always be found the "whitest" peoples, who are framed as "more civilized", and as we descend through the ranking, the peoples are increasingly coloured, where the bottom of the hierarchy is "the most primitive". Essentially, it creates a hierarchy of "good people" vs. "bad people", repeating the statements made by racial biologists a century ago, only, now it frames the ranking in terms of culture instead of race.
In Sweden, that ranking would have ethnic Swedes on top, as "the most enlightened, democratic, civilized and developed". After that come peoples from neighbouring areas, with Norwegians and Danes first, Finns and Sapmi last (they've always been at the bottom of the Nordic rankings). Then come other Western, Central Europeans and Anglo-Saxons, with Protestants higher and Catholics lower. Then comes the Mediterranean peoples and Eastern Europeans. After that come Latin Americans, followed by Asians and then Middle Eastern peoples. Africans come last, particularly Somalis. This hierarchy is not just a matter of perception, but so entrenched that it is found in the labour market. Swedes have the highest employment numbers, Somalis the lowest.
"Immigrants may bring homophobia, sexism or other bigotry"
Yet another way of invoking Huntington's "Clash of Civilization"-argument. This is a spin of the former argument, and equally targeted at racialized immigrants (mostly Muslims). Only, in this case it has been reframed and dressed with key values that most people in democracies will find anathema. The irony is that many nationalist parties tend to be weak when it comes to protecting the rights of non-ethnic subaltern groups. Their track records when it comes to women's rights, the protection of sexual minorities or those of disabled people are not impressive. Another irony is that the person who argues this effectively stereotypes a whole group of people, which is bigotry itself. Like all other categories of people, immigrants are diverse. Many migrants are actually moving because they have been persecuted by bigots and because they are pro-democracy and human rights activists.
Furthermore, if we are to take values like freedom of thought and freedom of speech seriously, this argument is impossible to sustain. You can't have a border control based on political opinion for a country that says that all citizens have the right to hold whatever political opinions they want. Notably, some countries have tried adopting policies that would "educate" newcomers about "acceptable values" in the host society, for instance the Netherlands and France. The data I've taken part indicates that integration outcomes for the Netherlands actually have taken a turn for the worse, so apparently the policy isn't working. That doesn't surprise me much, as the policy strongly signals that newcomers are not trusted. That is a poor way to welcome them.
"We should treat them like we would be treated in their country"
"They are radical and anti-democratic and will destroy our democracy and replace it with their totalitarian theocracy"
This one is usually used about Muslims who get stereotyped as radical fundamentalists. I'll let this man respond: