How does society move from one distinction to another? Good/evil is one traditional distinction, but, over the last century or so, it is has decreased in influence. Under the influence of sociology, it has been supplanted by normal/deviant. But a distinction is not a social system. Social systems use distinctions to observe whatever they observe. One issue is that in switching from good/evil to normal/deviant, communication shifts from morality to science.
But to address the how or maybe why question, evolution in communication happens when a contradiction arises, or when an undecidable decision arises. So if a communication system cannot determine whether an action is good or bad or no longer really cares whether it is good or bad, communication, if it is to continue, can draw a new distinction, such as normal/deviant, normal/abnormal, normal/exceptional, etc.
Evolution is marked by a discontinuity, or a break from business-as-usual, which is the condition under which expectations are confirmed or disappointed. As long as expectations are either confirmed or disappointed, then an expectation scheme works. If confirmation or disappointment of expectations no longer contribute to meaning, then the expectation must be dropped.
Body/soul is one distinction that is no longer very useful. We are more likely now to speak of life and death, and death is just the absence of life. Or can use the body/mind distinction or the brain/mind distinction. But the idea is that when the body dies the mind dies also. The concept of the soul is tied to the ancient ontology of essences, but it no longer works in a functionally differentiated society. The idea was that the soul doesn’t change; it’s a pure essence, but qualities of a soul (e,g., pure/corrupt, saved/damned) were changeable.
Another example of a distinction that has fallen into disuse is virgin/non-virgin. The question used to be asked (or at least thought about), is a person, particularly a woman, a virgin when she marries? Now that question isn’t really asked, except in cultures or subcultures that are still resisting modernity. In general, it’s not a useful distinction because it doesn’t add much to communication. If the question of a bride’s virginity is raised, the communication is likely to come to a halt because it’s seen as an irrelevant, antiquated, or stupid question, sort of like asking if a person a noble or a commoner.
The noble/common distinction declined not because it was untrue or even true; it’s not a question of true or false, it’s about the production of new information. Communication is driven by the need for information, and the noble/ common distinction ceased to yield information. There is no meaningful difference. To gain knowledge is to see difference, something new. When accused of crime, it doesn’t matter if you are a nobleman or a commoner. If you have money to spend or access to credit, it doesn’t matter if you are nobleman or a commoner. Under functional differentiation, the noble/common distinction doesn’t yield any real information.
Here is a Google Books ngram for the word nobility from 1700-2008. What’s interesting is that the use of the word was its highest at the time (1760s) when the the relevance of the nobility/commoner distinction was facing a serious challenge. As long it the distinction was taken as common sense, there wasn’t much reason to discuss it.
The 1760s was the decade of Rousseau’s most important work.