Some time ago I put an item on my blog in which I quoted several people saying that the difference in viewpoint between prescriptivists and descriptivists reflects a much deeper division regarding world view.
Here is a point at which I see such a division and my articulation of that gap in between world views:
The use of “their” as a kind of place holder for an indefinite item regardless of its number: thus “Every student should place their backbpacks outside” demands correction by the prescriptivists to “his” rather than “their” based on the misperception that the possessive adjective must reflect the number of its antecedent: if the antecedent, “student” is singular, the adjective must be “his” or “his or her”; “their” is admitted only for a plural antecedent, as in “All students should place their backpacks outside”.
Linguists and other observers of language have explained over and over that “their” marks an indefinite antecedent and is not restricted to plural antecedents. (I may not be explicating this all that well but I don’t want to take the time now to quote more detailed and clearer explanations)
Here is my wording of the prescriptivist view: while speakers may wish to use “their” with a singular antecedent and this may reflect some sort of “drift” in the language, and moreover the vast majority of speakers may follow this usage, people of rectitude and good mental discipline will follow the prescribed usage. Some loosen up to the degree that they allow the proscribed usage in informal, colloquial speech but not in formal speech or writing. Some prescriptivists go so far as to indicate the “popular” usage as a reflection of decay and mental laxity in the society. Anyone questioning this is not engaged on a linguistic level but on a moral level, engaged as an enemy of order, of high standards, of the best of civilization, and so on.
Linguists and what we might call “liberals” on the issue of usage argue that a survey of languages and of the history of English show many examples of such usages which have not led to any failure in communication or “corruption” of the language. Prescriptivists strike back by declaring that the languages descriptivists often cite are not bearers of major high civilizations and therefore do not reflect a high level of thought. In addition, they cite what they consider to be the moral corruption in current society brought about, in part, by lax standards in behavior and education, including language.
Given this deep divide, one must ask how likely it is that there will ever be a rapprochement in which an agreed upon curriculum can be designed.