This small but important section, "Of the Influence of Custom and Fashion upon the Sentiments of Moral Approbation and Disapprobation", addresses two major sources of mental stratification across different cultures. In a parallel to his discussion of utility, Smith believes that both custom and fashion affect aesthetics. To a lesser degree, he argues, they also affect morality.
Custom is the association one makes between two things which routinely accompany each other. Smith argues that this simple matter of association creates a sense of aesthetic pleasantness: if one is accustomed to certain architectural elements being seen together, these elements come to constitute a style, and one is pleased to see these elements all together. Seeing a style with an element missing would actually be unsettling because of the influence of custom.
Fashion, on the other hand, is derived from our admiration of people of status. Any particularity of aesthetics which these people adopt -- for example, a certain style of dress or appreciation for a certain artist --becomes valued by virtue of being associated with people of status. It follows, of course, that when people of status abandon a given style, it is no longer fashionable.
Because our moral sentiments are somewhat inherent, they are much more resistant to custom and fashion than our sense of aesthetics is; however, our moral sentiments are not immune to these influences. Where they coincide with our natural moral sentiments, custom and fashion only serve to heighten and enhance these sentiments; however, where they are opposed, they serve to make us less aware and more accustomed to what would otherwise be regarded as breaches of moral duty. Smith's words remind us that the conscience is quite impressionable -- at times, dangerously so.
It is this influence of custom and fashion, Smith argues, which accounts for major differences across cultures -- particularly across continents. While European countries disagree on issues of courtesy, other countries differ in more extreme ways: Smith refers to Native Americans as members of a "savage" society, one in which people are trained to endure the worst tortures in the event of capture, all the while expressing no pain (204-205). He similarly looks down on the infanticide which was reportedly practiced in ancient Greece.
In the case of aesthetics, Smith cites one Father Buffier in suggesting that beauty lies in the average appearance of things (196-197). This makes sense, Smith argues, because the average form is the form most often chosen by nature. Yet he concludes that standards of beauty are very different across cultures, with none of these standards being morally wrong. After all, different averages can occur within different populations: the average length of a human foot in England, for instance, is not equal to the average length of a human foot in China.
Smith makes no such corollary for the case of moral sentiments, because moral sentiments are designed by God; therefore, they are expressions of absolute truth, which is merely distorted by such things as custom and fashion. Yet Smith insists that true moral atrocities would never be accepted by people, regardless of their cultural dispositions, on account of this inherent sense of morality. Morality, he believes, is the most resilient part of human nature.
Although Smith is very biased towards his own culture, he uses this section to arrive at a compromise between two overarching moral belief systems, known as "moral relativism" and "moral absolutism." The former is a pedagogy which claims that morality is a construct established and enforced by the norms of one's culture; thus, there is no real "right" or "wrong" in an objective sense. The latter says just the opposite: there exists an absolute concept of moral goodness, which we are somehow able to access and know to varying degrees. Under the pedagogy of moral absolutism, all actions have definitive moral content regardless of culture.
It is clear that Smith is a moral absolutist, as is evident from his conviction that our moral sentiments are imparted to us by God. (God is arguably the most absolute concept which a philosopher can employ.) However, Smith also allows that morality is capable of being warped based on culture, even though morality cannot be completely destroyed because of its absolute foundation. To put the case clearly, Smith thinks that such distortion is typically a departure from true moral good, an entirely different position from the moral relativist's stance. Yet, unlike the most dogmatic moral absolutists, he acknowledges that a culture has a complex influence on the moral convictions of its people. Smith describes the corruption of morality by custom and fashion as a departure from natural propriety. He believes all people have inherently moral sentiments; those in barbaric cultures have simply had their worldview distorted, like a window that has been smudged but can still be cleaned.
This section also suggests the basic conflict between different societies: varying customs and fashions can cause populations' convictions to diverge, thereby creating friction. Depending on the degree of difference, this can result in a simple incompatibility in etiquette, or a source of violent conflict. Yet there seems to be no apparent remedy: as Smith says, what is average in nature varies across societies and across parts of the globe. So how could one truly reconcile, say, the accepted average standards in America and in Russia?
To pose another question, do the ways in which civilized nations diverge from moral truth resemble the ways in which certain aesthetic standards deviate from what is average? After all, Smith's language of nature choosing the most typical form of something invokes the notion of God's design. If that is the case, then the difference between aesthetics and morality would not seem to be as great as Smith suggests it is.