Which is an annoying use of the term “artificial intelligence,” to start with, and sounds pretty iffy in general. Polish your prose, eh? Let’s just see how this is supposed to work:
The Hemingway App … promises to do just that. “Hemingway makes your writing bold and clear,” the site claims, so that “your reader will focus on your message, not your prose.” If you listen to the app’s advice, it will rid your writing of run-on sentences, needless adverbs, passive voice, and opaque words. There’s no guarantee you’ll crank out the next Farewell to Arms — but the goal is to get you closer to Ernest Hemingway’s clear, minimalist style.
Ah! It will rid your writing of the passive voice! How useful! That way instead of writing something like, “Worst morning ever! My poor dog was hit by a car! She ran away crying and limping and it took me four hours to catch her. Thank God she was all right.”
Now you can write: “I had the worst morning ever! Someone hit my dog with their car! I mean, his or her car. Anyway, my poor dog ran away …”
And for all I know, the Hemingway app would also be offended by your exclamation points.
I see it costs $20 to get the app, and I don’t see a way to try it out for free, so the above sentences are just guesses about what the app might do. This is just an example of passive voice that shows how perfectly appropriate it can be when you actually do want to emphasize the object rather than the subject. Who cares about the car or the driver? The dog is obviously the important thing in the sentence. Passive voice allows that to be expressed.
Anyway, it turns out this app is not brand new. Here is an article from The New Yorker, written in 2014: Hemingway Takes the Hemingway Test
Take this description of Romero, the bullfighter, in “The Sun Also Rises”:
Afterward, all that was faked turned bad and gave an unpleasant feeling. Romero’s bull-fighting gave real emotion, because he kept the absolute purity of line in his movements and always quietly and calmly let the horns pass him close each time.
This breaks several of the Hemingway rules. The passive voice loses points, as do the two adverbs at the end. But “quietly” and “calmly,” are, of course, essential to the point. Bullfighters, masterly or not, avoid the horns most of the time. Only the artists like Romero manage it quietly and calmly. And that word, “quietly,” which is not quite literal, is a little surprise. Regarding the passive voice, it injects emotional uncertainty into the scene. “All that was faked turned bad,” scans like a melody, and in its passivity and slightly odd tense, feels like an elegy. It is not exactly clear. But it’s bold.
Amusing example! Also, an apt observation: I think we can assume that any app that zealously applies rigorous rules is going to produce text that lacks poetry.