The most recent usage thread led to two comments that I think might shed some insight into prescriptivist — or ostensibly logic-based — arguments about language:
[1] [T]here’s times when you want a prescriptivist. My daughter works at a fruit processing plant. They produce beverages and premixes for beverages. Besides checking the incoming and outgoing product for quality, she checks it for safety — swabbing tanks for microbial growth, logging pasteurizer temperatures, and so on; and she’s in charge of kosher certification too. Her employers need, and the consumers need, her to be fairly compulsive about things being just so. It’s hard to be that way about some things and not others.
[2] Funny to base one’s word usage on popularity, and it’s a good thing that medicine, engineering and other real thinking doesn’t work that way.
And I’d heard other such arguments before, sometimes analogizing a descriptivist approach to language to perceived retreats from an objective attitude towards science, history, and the like. Here’s why I think these arguments are mistaken.
In many fields of endeavor, the goal is to discover (or implement) some truth that is independent of people’s attitudes, and of social convention. In fact, the highest achievements in these fields often consist of proving something that is directly contrary to conventional wisdom. Physics, mathematics, medicine, and engineering are classic examples. The realities of physics, and the logic of mathematics, are out there independently of us and our society; we seek to discover the hidden law, which “takes the atom and the star and human beings as they are, and answers nothing when we lie.” Social convention may influence how we present our findings, how we organize our research teams, and other factors, but we’re ultimately trying to uncover or implement something true that is unrelated to its popularity.
But there are other fields of endeavor in which the rules are different. One field contains art, including the so-called fine arts, interior decoration, and esthetic design. There the goal is to find something that moves us or our listeners; to the extent we’re looking for “truth” in esthetics, that’s really poetic license for “something that we see as beautiful and that resonates in our minds with what we understand to be something true about the world.” Art that aims purely at popularity tends to be banal, but art that ignores the conventions of the genre and the tastes of its audience usually tends to be inaccessible and not very interesting to most observers.
Another field contains market research and similar disciplines. There the goal is precisely to figure out what the public likes, or what new things it might like. A business that wants to make product packaging isn’t looking for packaging that is “just so” in the sense of complying with objective rules, or that aims at the truth independent of popularity. It’s looking for packaging that will appeal to the public. I give these examples not because they’re identical to word usage, but just because they clearly (and, I hope, relatively uncontroversially) illustrate the difference between different fields.
On then to word usage. Language, unlike physics, is entirely a social convention. As I mentioned, the work of physicists is molded by social convention — the units they use, the way they write their papers, the credentials they expect from people they hire, and more — but there is an underlying reality to physics that is independent of society. But the English language is just a set of conventions used by English speakers, just like the Russian language is a set of conventions used by Russian speakers. The conventions are of course molded by physical reality, certainly as to the limits of the human mouth and ear, but also possibly by shared human psychology, which may go so far as influencing grammatical rules; but they are nonetheless social conventions. No-one (at least no-one reasonable) would talk about whether English, Russian, or Swahili most closely corresponds to some “true language,” the way doctors might ask which medical theories most closely correspond to the truth about human physiology. When people choose between languages that they can use, they generally choose based simply on what is likely to be most effective with their audience.
The same is true within what is generally understood as a language. Which is right: “color” or “colour”? It depends on the social convention of the particular subclass of English speakers with whom you are interacting. If you’re in America, “color” is the idiomatic choice, and if you want to communicate without distracting your audience, you will generally use that. If you’re in Britain, you’ll generally use “colour.” The right and wrong of the thing turns entirely on “popularity” in the sense of the expectations of the people with whom you are communicating. “Being fairly compulsive about things being just so” in the sense of following logical rules won’t get you far in this field, except when the rule you follow is “speak consistently with the linguistic conventions of your audience.” (I should note that the result may not turn entirely on majority vote; but it is certainly influenced by the views of the audience, and — returning to the subject matter of the original post — a usage that is highly uncommon is likely to not be effective.)
And the same continues to be true within a dialect. Why is “colonel” pronounced “kernel”? Why is it “ice cream” and not “iced cream”? Why is it “himself” (objective+”self”) but “myself” (possessive+”self”)? The acceptance, over time and throughout much of society, by the speaking, reading, and writing public.
No natural law dictates this (though some realities of human speech may influence it). No authoritative pronouncement of an official body dictates it, at least in America. Dictionaries help mold this, but they are themselves molded by it. Changes occasionally stem from concerted spelling reform campaigns, but only occasionally; and which such campaigns succeed and which fail itself turns on the acceptance by the public. “Prescriptivism” makes sense when it comes to food safety. The rules of microbial growth are “prescribed” by nature. It may make sense when it comes to following employer’s orders; the orders are prescribed by the employer, who has the authority to do so. There is no entity that has such authority when it comes to the English language.
So just separate these fields in your heads. Language doesn’t operate according to the same rules as physics or engineering, and it’s a mistake to bring certain attitudes from one of these fields to the other. You can seek objective truth in science that transcends the limitations and expectations of your society, but the only objective truth about usage consists precisely of what the relevant linguistic group does and expects. There is actually a lot of such objective truth out there: Google “I home walking” and you’ll see an example of just how rigid some rules of English grammar (which is to say the grammar actually used by people who write in English) can be. But it is objective truth about what is popular.