Correctness during the Enlightenment

What fascinates me most about this period—and annoys me—is the obsession with correctness. Blair particularly writes in detail about how development of “proper taste” leads to improvement of character, that when one speaks and writes properly, one is morally superior. This isn’t a new idea: I think Aristotle was one who touched on the idea of developing the mind’s faculties and becoming more virtuous, but during the Enlightenment period, something different was happening. After hundreds of years of the feudal system, two factors—as I understand it—played into shifting power out of the hands of the nobility. One was the black plague. Thousands and thousands died, mainly those who were responsible for working the land and growing food (little access to good food and doctors). Suddenly, the peasant class had a little bargaining power since healthy workers were hard to find. Secondly, the industrial age had begun and a true middle class began to arise. I’m really oversimplifying it, but basically, during the Enlightenment, the merchant class had burgeoned into a consuming public. The population centers were shifting as well, with people flooding into cities looking for work in the new factories as many landowners, faced with a dearth of workers, turned to sheep farming.
With the rise of a middle class which wasn’t sure where they stood in a world that valued those with power and wealth (oh, like that’s any different), a concern over class identification also arose. In earlier centuries, you were a member of the class you were born into, and there was little room to move upward: you were noble, or you were a peasant. Many rules applied to help keep the population pegged into the right holes: only the King could wear a certain type of fine fabric or fur such as ermine, a lesser noble could wear fox-fur, and peasants could only wear homespun wool, etc. These rules applied to education as well. Ruling class or working class. Now, with a prosperous middle class of “common” birth, the question arose as to how one could tell what class a person belonged to. How could you tell who had privilege? You could say that this middle class was extremely class-conscious, and they had serious nobility-envy. They wanted to speak as the members of the ruling class did.
Also, to keep oversimplifying because I don’t want to write hundreds of pages, we see the development (after the printing press) of a desire to standardize English just as French and—I think—Italian had been. These latter languages had universities and committees devoted to preserving the language. The idea was that change in a language meant deterioration, thus rules must be set in stone as to what was correct. Also, a language only has status when it is used by those with power, can be taught, and has rules of usage to follow. A dictionary is vital to this. Samuel Johnson produced the first substantial dictionary, and he felt strongly that language should be fixed and not be “polluted” by a haphazard introduction of foreign words. Unfortunately for him, English is a language that adapts easily and quickly to foreign words, having its own roots in old German, but many other languages as well, all blending together into a fantastically flexible system. Believe it or not, our “unpredictable” methods of spelling can be predicted by a computer programmed with just a few guidelines to follow.
I apologize for focusing so much on linguistics, but I think this is important to understanding why there is such an obsession with correctness in the way writing is taught even today. What surprises me most about the Enlightenment period, however, is that the birth of the study of language truly blossomed here, whether anyone in influence over the universities took notice or not. Sir William Jones (page 801 of BH) noticed through intense study that Latin, Greek and Sanskrit had to have had a common source. This realization led to the understanding—at least on the part of linguists—that language does change and grow, just like everything else on earth.
One last point: Cicero made a comment that he felt that rules of usage should be based not on ancient, fixed rules, but on common usage of educated, respectable people in society. George Campbell (801 of BH) also felt that “prevailing custom” should set the standards. These are, unbelievably, issues still under passionate debate. There was a fantastic show on PBS just last year about language use and dialect in the USA, and prescriptive (rules of usage) grammar versus descriptive (how do people use language?) grammar.
My question: I’m having a lot of trouble with page 799-800 which details concepts talked about on page 792: espistemology, semantics, other scientific theories in play. Anyone with a logical brain who can help me understand these ideas?