il Rights Movement, which criticized ideals of assimilation that often led to prejudices against those who did not act according to Anglo-American standards and which led to the development of academic ethnic studies programs as a way to counteract the neglect of contributions by racial minorities in classrooms. As this history shows, multiculturalism in Western countries was seen to combat racism, to protect minority communities of all types, and to undo policies that had prevented minorities from having full access to the opportunities for freedom and equality promised by the liberalism that has been the hallmark of Western societies since the Age of Enlightenment. The contact hypothesis in sociology is a well documented phenomenon in which cooperative interactions with those from a different group than one's own reduce prejudice and inter-group hostility.
C. James Trotman argues that multiculturalism is valuable because it "uses several disciplines to highlight neglected aspects of our social history, particularly the histories of women and minorities [...and] promotes respect for the dignity of the lives and voices of the forgotten. By closing gaps, by raising consciousness about the past, multiculturalism tries to restore a sense of wholeness in a postmodern era that fragments human life and thought."
Tariq Modood argues that in the early years of the 21st century, multiculturalism "is most timely and necessary, and [...] we need more not less", since it is "the form of integration" that (1) best fits the ideal of egalitarianism, (2) has "the best chance of succeeding" in the "post-9/11, post 7/7" world, and (3) has remained "moderate [and] pragmatic".
Bhikhu Parekh counters what he sees as the tendencies to equate multiculturalism with racial minorities "demanding special rights" and to see it as promoting a "thinly veiled racis[m]". Instead, he argues that multiculturalism is in fact "not about minorities" but "is about the proper terms of relationship between different cultural communities", which means that the standards by which the communities resolve their differences, e.g., "the principles of justice" must not come from only one of the cultures but must come "through an open and equal dialogue between them."
Balibar characterizes criticisms of multiculturalism as "differentialist racism", which he describes as a covert form of racism that does not purport ethnic superiority as much as it asserts stereotypes of perceived "incompatibility of life-styles and traditions".
While there is research that suggests that ethnic diversity increases chances of war, lower public goods provision and decreases democratization, there is also research that shows that ethnic diversity in itself is not detrimental to peace, public goods provision or democracy. Rather, it was found that promoting diversity actually helps in advancing disadvantaged students.
Wikimedia Foundation suggests that "diversity of perspectives is crucial to increasing the quality of the free knowledge resources that [their] movement provides.". Wikidata also suggests that "the world is complicated and there is no single [consensus—especially in a knowledge base that is supposed to serve many cultures."
Critics of multiculturalism often debate whether the multicultural ideal of benignly co-existing cultures that interrelate and influence one another, and yet remain distinct, is sustainable, paradoxical, or even desirable. It is argued that nation states, who would previously have been synonymous with a distinctive cultural identity of their own, lose out to enforced multiculturalism and that this ultimately erodes the host nations' distinct culture.
Harvard professor of political science Robert D. Putnam conducted a nearly decade-long study on how multiculturalism affects social trust. He surveyed 26,200 people in 40 American communities, finding that when the data were adjusted for class, income and other factors, the more racially diverse a community is, the greater the loss of trust. People in diverse communities "don’t trust the local mayor, they don’