Oh, my. Read it again. It doesn’t get better, does it?
Now, I have nothing against double negatives. They come in very handy in expressing shades of meaning: “I don’t not like him; I just don’t want to date him”; “The sensation is not unpleasant.” More time in thought might produce other ways of making the point—other words, other structures—but those ways might not necessarily be better, especially for conveying attitude or establishing tone.
In informal, vernacular, or dialogue writing they can also be great for emphasis: “I don’t NEVER want to see your face NO MORE.”
I think, though, that my student wasn’t actually purposeful when he wrote his sentence. I think he just got lost.
He was commenting on an entry in Dorothy Wordsworth’s Grasmere Journals. She observed that although she herself noted and appreciated the small changes in the countryside from one day to the next, people for whom the landscape was merely the environment—people like the postman, for instance, who walked the same route every day in the course of working—were often oblivious to the changing life around them. But what his comment is meant to convey I cannot with any certitude say. Therefore I couldn’t even suggest changes to help him convey it.
If we assume that “two negatives make a positive” (which outside of arithmetic they often don’t, but let that go), does he mean most people ARE familiar with Wordsworth’s idea—it’s a concept that most people are familiar with? If his point was that her observation is nothing new, then why did he dedicate his own Journal entry to it?
But if we try to read the two negatives as somehow introducing subtlety or attitude, we can’t come up with much. “This isn’t a concept that most people aren’t familiar with, but it’s a concept that some people aren’t familiar with”? Why not say that, then?
That leaves the explanation I believe to be THE explanation: He started off wanting to say that this concept (presumably that people overly accustomed to a thing don’t really notice it anymore) is probably new to most people, and therefore wrote “This isn’t a concept that most people….” Not a great beginning: wordy and clumsy. I generally advise student writers to try to avoid negating the verb with “not,” but instead to make the sentence negative through vocabulary choice, and this sentence is one example of why. Couldn’t he have written “This is a concept that few people…,” or even “Few people are familiar with this concept”? Be that as it may, this student ignored that advice as he began his sentence. So far, so (kind of) good.
But then something happened. Did some friend text him, or phone him, or email him, or otherwise intrude into his concentration? Did he fall asleep? Did he suddenly realize he was hungry, and leave his computer to get a snack or go to dinner? Did he have a moment of insanity?
Whatever it was, when he brought his mind back to the screen he didn’t really read what he had already written; he just went forward with his intention to point out the originality of Wordsworth’s insight. “Most people aren’t familiar with” it. Hang that “aren’t familiar with” on, type another vaguely enthusiastic sentence or two, and so to bed.
People who take pleasure in putting the language through its paces sometimes decide to violate a “rule of grammar” to say what they mean with precision and effect. People who don’t really pay attention to what they’re writing—like postmen trudging down the spring lane intent only on reaching the end of their route—miss all the fun, and sometimes don’t even wind up where they meant to go.
And I ain’t got NO patience with them!