I have sometimes been critical of “multiculturalism“. But it is clear that I use the word in a different way from many other people, and I have probably anyway been muddled about what I mean by the word. So I’ll try to clarify how I use the word, and what my opinions are about multiculturalism.
Culture and multiculture
Start with “culture“. I’ll go with Wiktionary, at least for the time being:
“The arts, customs, and habits that characterize a particular society or nation”.
“The beliefs, values, behaviour and material objects that constitute a people’s way of life”.
The single most important thing about these definitions is that “culture” is a totally different concept from “race“, which I use here in the biological (but still contentious) sense. So people of a single race (whatever that means) may have a number of cultures, and the people with a particular culture may be of a number of races. I always keep this separation in mind, and never use one word when I really mean the other.
“Multiculturalism” is used in different ways, but it should always be used in connection with having multiple cultures within a given domain. As with “culture”, it is a different concept from anything like “race”. “Multicultural” does not mean “multi-racial”. You can’t count the number of different skin colours (or other determinants of race) in a crowd and determine whether the crowd is multicultural. Multiculturalism may refer to a policy to have multiple cultures, or the methods of having a successful society with multiple cultures. These should overlap anyway.
So, can there be good or bad cultures? Of course there can! But the judgment will depend on the values used to make the judgment. I use the “Dimensions of Enlightenment” to judge whether a culture is enlightened, and consider that enlightened=good and unenlightened=bad. (There is more to it than that! In particular, it depends on whether all people concerned treat cultural practices as hobbies. If so, good! But if they demand privileges for their culture than other hobbies don’t have, conflict is likely).
Multiculturalism that includes unenlightened cultures is likely to be undesirable. But is multiculturalism always OK if all the cultures are enlightened? I think “not necessarily”. It depends on whether they are integrated constructively so that they can coexist peacefully. Cultural groups should be integrated, not isolated. The target should be to have at least two (preferably more) of the following, including the first:
Able to speak English (or optionally Welsh in Wales)
Lack of English imposes a translation cost on government services, inhibits employment which adds further burden on taxes, increases suspicion (both ways), and tends to disenfranchise people. In fact, generous provision of translation services is supporting ghettoisation by removing the motivation to learn English, and should be restricted to emergencies involving visitors and recent immigrants. Lack of English often primarily affects women.
No fixed principle is provided here, but areas where schools take children mostly from a single culture other than the surrounding, perhaps majority, culture are a concern, as are “no-go” areas.
Inter-trading with other groups
This is perhaps one of the most visible success stories of some earlier immigrant cultures. People who are trading with one another have reasons not to be in conflict with one another. There are obvious benefits from having employment and not being a burden on the state. And the UK is a better place as a result of what various cultures imported: perhaps a third or more of my meals had such origins!
Inter-partnering & inter-marriage
For some cultures this is problematic. But the reasons behind these problems may show that there are deeper conflicts.
Given the definitions of culture and religion they obviously overlap a lot. Religion often dictates aspects of a culture. And aspects of a culture influence the religion(s) it originates.
Most of what I am saying here applies to having multiple religions (plus atheism, of course) within a domain.