Thanks for providing the source.
The original source appears to be Rimbaud the Son (available at amazon.com)
by Pierre Michon, whose first language appears not to be English,
so it’s a valid question to ask whether this is correct English.
I would add a comma: “if anything, less,”
and maybe change the comma after “less” to a semicolon
(and maybe also the comma before “if anything”).
I agree with snailboat’s answer, but let me approach it from a different angle.
I’m a mathematician at heart, and, mathematically, if X and Y are real numbers
(no imaginary component), then one of three conditions must be true:
Here X is how much “one one who writes them” knows, and Y is how much we know.
The author is saying that X is not greater than Y
(“the one who writes them does not know any more than we do”),
which leaves the other two possibilities:
X = Y (“the one” knows as much as we do) or X < Y (he knows less than we do).
The “if anything less” phrase means
that the author is not ruling out the X < Y possibility;
“the one who writes” [works of declared genius] may, in fact,
know less than we, the readers, do.
In case you’re still having trouble with the construction, here’s a simpler example:
John is not taller than six feet; if anything, less.
which is to be understood as
John is not taller than six feet; if anything, he is less tall.
Regarding the punctuation before “when fitting”, refer back to my first point.
I believe that this book was written in French, so
- maybe it’s a bad translation,
- maybe it’s a good (faithful to the original) translation,
and we should be asking about the rules of punctuation and sentence structure in French,
- maybe this is just the author’s style, and he doesn’t care about the rules.
In fact, the excerpt in The New Yorker (your primary source) misquotes the book.
The sentence actually doesn’t even end at “and it is over”;
it goes on for another 62 words, for a total of 146!
So, I guess we can conclude
that Michon really, really, really, really, really, really, really likes run-on sentences.