We affirm that some cultures operate on assumptions that are inherently better than those of other cultures because of the biblical truths that inform those worldviews that have produced these distinct assumptions. Those elements of a given culture that reflect divine revelation should be celebrated and promoted. But the various cultures out of which we have been called all have features that are worldly and sinful—and therefore those sinful features should be repudiated for the honor of Christ. We affirm that whatever evil influences to which we have been subjected via our culture can be—and must be—overcome through conversion and the training of both mind and heart through biblical truth.
We deny that individuals and sub-groups in any culture are unable, by God’s grace, to rise above whatever moral defects or spiritual deficiencies have been engendered or encouraged by their respective cultures.
I see the authors addressing two issues here. First, the popular notion that all cultures are equally good and that differences among them are a matter of legitimate diversity rather than better or worse. Second, that human beings are simply products of their respective cultures.
Let's take up the first issue. Richard Mouw and Sander Griffioen have isolated three kinds of diversity that characterize life in community. The first is directional diversity, or the plurality of ultimate and penultimate beliefs that characterize our society. The second they call contextual diversity, which describes the different ways that communities separated from each other by time and geography go about organizing their common life. The third they label associational diversity, but I prefer societal pluriformity, to describe the different sorts of communal structures existing in a differentiated society.
In speaking of culture, the second form of diversity—contextual—is most relevant. Because we are limited creatures spread across a wide swath of the earth's landmass, our local communities develop in different ways, speaking different languages and dialects, relying on different foodstuffs, singing different songs, playing different musical instruments, developing different modes of social intercourse, and so forth. At one time our forebears spoke of culture as though it were a singular process leading from savagery to civilization. Now we are more likely to speak of cultures or civilizations in the plural, recognizing the legitimate diversity in the ways people relate to their god(s), to each other, to their traditions and to their physical environment. No one can doubt that the Greeks and the French are quite different in many respects. Even inside France we find people speaking different dialects and languages, which the highly centralized French educational system has long attempted to suppress in the interest of national unity.
Are all cultures equal? Well, it depends on what sort of equality we have in mind. That people form different cultures is inevitable and, arguably, a good thing. In this respect one can say that multiple cultures are equally valid. There is little to be said for making Pacific islanders into Englishmen or Americans. Are some cultures superior to others? Once again, we would have to define superior. Some cultures are better than others in maintaining stable legal systems and incorruptible justice systems. There is such a thing as a culture of corruption which we do well not to emulate. Some cultures have high levels of interpersonal trust outside extended kinship communities and, because of that, are better able to join together in co-operative economic ventures for their mutual benefit. In other cultures, people do not generally trust each other beyond their own family networks, thereby rendering horizontal ties of solidarity more difficult to form and maintain. Such cultures are likely to remain impoverished in several respects, and not just economic. Robert Putnam's fascinating study of the Italian regions demonstrates that culture matters to the health of political institutions. Where dysfunctional personal and social habits are ingrained in a particular culture, it will be that much more difficult to secure constitutional governance and economic prosperity.
In short, some cultures are better than others at maintaining themselves over the long term and at facilitating the development of flourishing political, economic and other institutions.
Now to the second issue. The statement denies "that individuals and sub-groups in any culture are unable, by God’s grace, to rise above whatever moral defects or spiritual deficiencies have been engendered or encouraged by their respective cultures." Yes, but not everyone will do so. My own experience tells me that, when individuals are transplanted from one cultural environment into another, they generally function well within the second. Many Italian Canadians have origins in southern Italy, where the civic culture has been slow to develop and where vertical patron-client relations retard the building of horizontal ties of solidarity. Southern Italy is much poorer than the north because of this. However, once immigrants from the south come to Canada, they appear easily to adapt to the ways of the host country, running their own businesses and contributing positively to our common public life.
However, members of our First Nations on the reserves and African Americans living in the ghettos of Chicago and St. Louis generally find it difficult to escape their circumstances and to do well for themselves due to real obstacles in their way. By God's grace some are able to overcome the hurdles and contribute to the larger society. We rightly thank God for this. But very many do not, and these are the people we need to pay attention to and offer whatever assistance we can for the betterment of their lives.
Next and finally: racism.