Caveat: what follows are only some rough, preliminary notes, made at the beginning of serious inquiry into the debates on this subject.
Let’s imagine culture X in which a certain worldview, X1, predominates. Let’s imagine also that a member or members of culture X assert that X1 is superior to all other worldviews, including the worldviews of other cultures.
Here are some arguments against that assertion.
These argument apply to assertions of the superiority of any culture. The logical implication is not that all cultures are equal, but that hierarchical ranking of cultures (even to rank them all as equals) is meaningless.
The Intrinsic Argument
One can argue that worldview X1 rests on categories of perception and thought which are universal to the human mind, which therefore makes X1 universally valid.
Such arguments would be valid if the categories of human thought were determined solely by our shared physiology.
This is not the case, however. Basic categories of thought and perception, including time and space, involve a mix of physiologically determined and culturally constructed elements.
Therefore no worldview X1 can be universally valid on intrinsic grounds.
The Extrinsic Arguments
The supremacy of a a cultural worldview is sometimes argued on grounds of the perceived extrinsic consequences of that worldview. The assumption is that if practice Y is linked to worldview X1, then X1 has caused Y and the value of Y translates “back” to the the value of X1. This is a problematic assumption. But but even if we grant it for the sake of argument, we can rebut its various applications.
The Argument from Linear Evolution
Evolution is sometimes portrayed as a linear process of overall improvement. This is a mistake. Evolution is a nonlinear process in which permutations of a system (whether physical, biological, or social) spread outwards from one niche to occupy available adjacent niches.
A human culture is a complex multidimensional system, full of internal conflicts and contradictions as well as harmonies and complementarities.
Cultures, like other complex systems, develop through a process of adaptation to their environments. This process is nonlinear: what is adaptive for one environment is maladaptive for another. It is also nonlinear in that the culture itself modifies its environment, creating recursion and blurring the culture/environment boundary.
We cannot use time to place cultures on a linear track. All living human cultures have been evolving for the same amount of time and in this narrow sense are ‘equally evolved’.
The Argument from Pragmatic Progress
One can argue that culture X has, on the basis of worldview X1, produced pragmatically superior technology and/or social organization.
For instance, Westerners can point to the superior efficacy of modern medicine, the superior productivity of industrial technology, etc.
This argument is intuitively appealing, but commits one of two fallacies:
A) a fallacy of composition, generalizing from one aspect of a culture to the culture as a totality.
Specific cultural practices can have the property of linear development, but a culture as a whole cannot have this property. This is because cultures are complex multidimensional systems, adaptively specialized for different environments. Fitness for one environment does not equal fitness for other environments; often, fitness for one environment entails lack of fitness for certain other environments. Cultural change cannot be validly reduced to progress or lack thereof along a single dimension.
B) a fallacy of cherry picking, choosing only those aspects of a culture which can be construed as superior and ignoring those which cannot.
For instance, the same modern Western culture that has produced industrial technology has also produced anthropogenic global climate change, which threatens the survival of the entire human species. There is no valid way to balance these two against each other quantitatively to determine that one outweighs the other.
Cherry picking could be justified if one could objectively value certain aspects of a culture over others. However, any such value-judgment is itself culture-dependent.
The Argument from Moral Progress
One can argue that culture X has, on the basis of worldview X1, produced morally superior outcomes: piety, human rights, etc.
The same fallacies of composition or cherry picking apply here, especially the latter. Moral goods can emerge as one pole of a contradiction within a culture. For instance, modern human rights ideology has emerged in the contexts of struggles against slavery, genocide, and state authoritarianism. The same culture that produced the UDHR also produced the Holocaust, and again there is no valid way to balance these two against each other quantitatively to determine that one outweighs the other.
In addition, the value of a moral good, its very status as a moral good, is culture-dependent. Asserting the superiority of a culture on the grounds of its superior moral values is, ultimately, a circular argument.
If we allow the extrinsic applications of a worldview to count towards its value, then to be consistent we must also allow the extrinsic applications of the argument for cultural superiority itself to affect the value of making that argument.
Arguments for cultural superiority have many negative consequences. Such arguments have been used, historically, to support military aggression, conquest, slavery, colonialism, and genocide.
It is currently still used to justify cultural genocide of indigenous peoples, and to feed into the fallacious belief in a “clash of civilizations”.
Conversely, arguing the superiority of one’s own or another culture has only one very limited positive consequence. If the argument is made on behalf of a culture that has been subordinated and pressured towards extinction, the argument might help push back against that genocidal impetus, at the cost of being vulnerable to the refutations above.
Otherwise, the argument has no positive consequences that I can see.