As it stands, i don't care how you say the plural of octopus, but if you say something "begs the question" that better end your sentence, you plebe.
[0]https://en.wikipedia.org/wiki/Moving_the_goalposts
Also, the colloquial meaning of "begs the question" doesn't always have a good alternative. Sometimes, a situation doesn't just "raise the question" like some tired bureaucrat raising his hand in a meeting. Sometimes, the question is too immediate and obvious to just be ignored. It's the elephant in the room. It cries out to be answered. It begs.
Allowing "begs the question" doesn't degrade the expressiveness and utility of the language, it improves it. This is unlike, for example, the misuse of "literally" (which results in there being no easy way to indicate that a statement should not be interpreted figuratively).
(This, by the way, is my personal test for whether a language rule is useful or not.)
I'd say that in every case that it is used in its classical sense when heard by person who uses it to mean "raises the question." Using "begs the question" that way is an actual mistake. One can have only heard "begs the question" used properly, but if you weren't familiar with the phrase, easily and understandably take it to mean "a question is begging to be asked", then go on to use it incorrectly.
Using the phrase "begs the question" incorrectly is probably only an hour younger than the phrase itself. Correcting someone about it without completely explaining its actual meaning (because you'd have to, at the least, explain the difference between formal and informal fallacies) is about a minute younger than that.
It's hard to make a case for it being language evolution if the incorrect usage is as old as the correct usage, and isn't growing any more than proportionally with it.
People being upset about being corrected about it isn't new either. People who use it correctly will continue to use it correctly, and people who use it incorrectly will use it correctly after they learn formal fallacies and can't think of a better, pithier way to describe that particular one.
Using it incorrectly, of course, is a sin akin to using an eggcorn (http://eggcorns.lascribe.net/) : everybody has misheard or misunderstood many things, and then misuses them. The problem with finding them is that one has to use them in a conversation with someone nice enough or brave enough to correct one.
I'm not saying this is impossible, but I don't find it convincing. The formal usage is something that a person does, and is usually the end of a statement. ("You're begging the question.") The colloquial (not "incorrect") usage is something that a situation does. It is nearly always rendered in the third-person present tense and directly followed by the question it is introducing. ("Well, that begs the question: what do we do about it?").
I don't see how somebody could hear only the first version, and end up saying only the second version. I can see how someone could be confused the first time they hear the first version (i.e., "Wait, what question is he referring to?") and would need to have the term defined for them. But that's pretty much the definition of "jargon".
- "Assuming something big enough to obviate the question": e.g. "They said the searches were legal because they were limited to what was absolutely, but that just begs the question: what are they counting as necessary?"
- "Raises the question": this can be an case of the previous, but it can also be something like "They said the searches were legal, which begs the question of how often law enforcement is conducting searches under those criteria."
I think a better example of the point you're making is what the GP said about "literally" -- it's extremely useful to have a context-free indicator (just like e.g. specialized legal, military, or EMS jargon) that allows the listener not to have to guess. Using it as a generic intensifier then forces listener to guess when the whole point of such a word is to avoid that.
Even if "literally" is a lost cause, people should still coordinate on some word, but that doesn't work if they keep pushing each one down the intensifier treadmill.
Then it's kinda strange that the very same people who are promoting this non-prescriptivism are also rolling their eyes at the "literally-misuse-objectors" and dismissing their complains as baseless for the same reason.
I've also mostly given up on "literally", which I think is worse, because it's now coming to mean its opposite.
The idea is that there are two groups of people, one holding to an original meaning, and one with a new usage. Sometimes the new meaning can be directly opposite the original meaning (e.g.: nonplussed), or just different (e.g., hopefully).
So, writers who wish to be understood cannot use "nonplussed," because readers will not know what is meant. A skunked term.
A longer explanation: http://englishcowpath.blogspot.com/2014/11/skunked-terms.htm...
"That's so bad!" meaning "That's awesome!"
If I can go on a tangent about poor terms...contranyms will throw people for a loop if they are unaware of one of the meanings. Or worse, if the sentence is constructed in a way meant to cause confusion.
"I would be bound for Chicago if I wasn't bound to this chair." [0]
"It is transparent that the transparent man cannot be seen." [1]
"Three people are left after five left." [2]
"If we go back two weeks, when Tom came back, we decided to push the date back three weeks." [3]
[0] I would be moving towards Chicago if I wasn't unable to move from this chair.
[1] It's visible to anyone that the invisible man cannot be seen.
[2] Three people remain after five departed.
[3] If you go into the past two weeks, when Tom returned, we decided then to push the date further by 3 weeks.
I had fun writing those.
As long as by "now" you mean, "over the last several hundred years":
My daily bread is literally implored I have no barns nor granaries to hoard;
John Dryden, The Hind and The Panther (1687)
Every day with me is literally another yesterday for it is exactly the same.
Alexander Pope, Letter to H. Cromwell (March 1708)
His looks were very haggard, and his limbs and body literally worn to the bone
Charles Dickens, Nicholas Nickleby (1839)
If we were not perfectly convinced that Hamlet's Father died before the play began, there would be nothing more remarkable in his taking a stroll at night, in an easterly wind, upon his own ramparts, than there would be in any other middle-aged gentleman rashly turning out after dark in a breezy spot -- say Saint Paul's Churchyard for instance -- literally to astonish his son's weak mind.
Charles Dickens, A Christmas Carol (1843)
He is a fortunate man to be introduced to such a party of fine women at his arrival; it is literally to feed among the lilies.
Frances Brooke, The History of Emily Montague (1769)
I look upon it, Madam, to be one of the luckiest circumstances of my life, that I have this moment the honour of receiving your commands, and the satisfaction of confirming with my tongue, what my eyes perhaps have but too weakly expressed — that I am literally the humblest of your servants.
George Colman and David Garrick, The Clandestine Marriage (1766)
Lily, the caretaker's daughter, was literally run off her feet.
James Joyce, The Dead (1914)
that he had shared her bedroom which came out in the witnessbox on oath when a thrill went through the packed court literally electrifying everybody in the shape of witnesses swearing to having witnessed him on such and such a particular date in the act of scrambling out of an upstairs apartment with the a ssistance of a ladder in night apparel...
James Joyce, Ulysses (1922)
And when the middle of the afternoon came, from being a poor poverty-stricken boy in the morning, Tom wasliterally rolling in wealth.
Mark Twain, "The Adventure of Tom Sawyer" (1876)
All colors made me happy: even gray.
My eyes were such that literally they Took photographs.
Vladimir Nabokov, Pale Fire (1962)
Literally, I was (what he often called me) the apple of his eye
Charlotte Bronte, Jane Eyre (1847)
(try and disagree with me, some of my words mean the opposite of what I intend)
A better example is nice, which started bad (meaning "foolish" or "silly"), achieved a positive meaning in 18th century and on it's way down again ("How's my coding? It's nice.") Full story and some other interesting examples are here: http://blog.oxforddictionaries.com/2012/10/change-in-word-me...
OK, can't help it, another interesting example. The word slut, of unknown origin, was first applied to men and then generally applied to kitchen maids with a mild negative meaning of slovenliness (https://en.wikipedia.org/wiki/Slut, http://www.etymonline.com/index.php?term=slut). There are other words starting with sl- that made a similar journey but are now fell out of use, e.g. slattern and slammerkin
I swear someone uses the word 'granular' about once every fortnight and I almost always have to ask what they mean because it's not usually obvious from the context.
Also, analogies provide explanation, not proof. You've not provided any justification for your opinion with your map analogy, you've just over-explained your opinion which everyone already understood.