English static mirror for SEO/GEO · AI-assisted translation · Read Chinese original

Why LLMs Love the 'Not X, But Y' Pattern: Artificial Epanorthosis Explained

Forum topic · ✨步子哥 · 2026-07-24

Summary

Large language models systematically overuse the 'not X, but Y' rhetorical pattern known as epanorthosis, a classical figure catalogued by Cicero and Quintilian. A 2026 paper by Federico Boggia, 'Artificial Epanorthosis,' traces the cause not to autocratic generation mechanics but to training: marketing-heavy web corpora plus RLHF rewarding confident, emphatic prose. Boggia introduces an Epanorthosis Index comparing model density to human baselines, finding a genre-specific miscalibration—models overshoot roughly 2x in speeches but undershoot in informal Q&A, with larger models amplifying the mismatch. Mitigation tests show a single prompt instruction cuts density 50-75%, while LoRA fine-tuning with a tunable scaling coefficient nearly eliminates it, enabling calibration to human baseline rather than elimination. The paper warns of a feedback loop: as AI text floods the internet, humans increasingly imitate machine rhetoric. arXiv:2607.21498.

You scroll through LinkedIn and see: "This isn't a course. It's a transformation journey." Then: "We don't sell products. We craft experiences." Your instinct says: AI wrote this. You're right—but what you may not know is that this "not X, but Y" pattern has a 2,000-year-old name: epanorthosis, a classical rhetorical figure catalogued by Cicero and Quintilian in ancient Rome. Why would a language model that knows nothing about rhetoric systematically reproduce a technique from two millennia ago?

Federico Boggia's July 2026 paper, *Artificial Epanorthosis*, digs to the bottom of this phenomenon.

A Tell You Can't Unsee

Epanorthosis comes from Greek *epi* (upon) plus *anorthosis* (correction)—literally "correcting again." The speaker makes a statement, then immediately revises it, replacing the original word with something stronger, more solemn, or more elevated. Classical rhetoric distinguishes three uses:

  • Emphatic correction: replacing a word with a stronger one — "He is good, nay, excellent."
  • Mitigated correction: replacing with a milder one — "I'll kill you—or, well, at least scold you."
  • Redefining correction: overturning and restating the whole claim — "This isn't a course, it's a transformation journey."
  • The third is the LLM favorite. Boggia notes it has proliferated across chatbot answers, LinkedIn posts, and marketing copy—"impossible to unsee once seen."

    The Cause: Not Generation Mechanics, but Training Preferences

    The natural guess is that it's a byproduct of autoregressive left-to-right generation: the model says a word, then revises it. But Boggia argues this is only an amplifier, not the root cause. There are two real sources:

    First, the training distribution is saturated with marketing prose. The highest-density "not X, but Y" corpora on the internet are ads, marketing copy, LinkedIn posts, and TED talk scripts. The model learned that this pattern "sounds powerful."

    Second, RLHF rewards it. Preference tuning has human annotators scoring confident, emphatic, compelling answers highly. Epanorthosis is the cheapest tool for manufacturing emphasis—one sentence upgrades a mundane statement into a quotable line. Annotator preferences become internalized generation tendencies.

    The evidence: base models show lower epanorthosis density than instruction-tuned models, and density rises with model size. If it were a byproduct of generation mechanics, base models would show it equally. Instead, the later the training stage, the heavier the tell—training reinforces it; the architecture doesn't produce it.

    The Epanorthosis Index: Turning "Vibes" into Numbers

    One of Boggia's core contributions is a measurable metric: the Epanorthosis Index—the model's epanorthosis density in a given genre, divided by the human density in the same genre. An index of 1 means human-equivalent; above 1 means overuse.

    Measured across one instruction-tuned model family at three sizes, the results reveal a genre-specific mismatch:

  • Speeches: models overshoot ~2x (nearly 3x in Italian), concentrated in larger model tiers
  • Informal Q&A: models undershoot, using it less than humans
  • Argumentation, news, encyclopedia: roughly human-level
This is the key finding: models don't blindly overuse epanorthosis—they overuse it where restraint is needed and underuse it where it fits—a systematic, genre-specific miscalibration. Larger models are worse, meaning scale amplifies the miscalibration rather than correcting it.

Mitigation: One Prompt Line Halves It, LoRA Nearly Eliminates It

Boggia tested three mitigations, experimenting in Italian:

A single instruction: adding "do not use 'not X, but Y' corrective constructions" to the prompt cut density by 50–75%. Blunt but effective—the tendency is instruction-controllable.

LoRA fine-tuning: a small supervised adapter trained to reduce epanorthosis nearly eliminated it. Crucially, LoRA's scaling coefficient acts as a knob to tune the reduction precisely back to the human baseline—not elimination, but calibration.

The goal is calibration, not elimination: Boggia stresses this repeatedly. Epanorthosis isn't bad—Cicero used it, Churchill used it, good oratory requires it. The problem is runaway density in contexts that don't need it. The right target is returning model density to the human baseline in every genre.

The Real Risk: We Start Writing Like Machines

The paper's final line is worth quoting: "The real risk is that we start writing like machines."

This isn't alarmism. As LLM text floods the internet—students using ChatGPT for essays, marketers for copy, job seekers for cover letters—epanorthosis density will compound through a feedback loop of "humans imitating AI text." We already see LinkedIn posts resembling chatbot output: it's not humans using epanorthosis, it's humans imitating the machine's epanorthosis.

Boggia's paper does something rare: it turns a "something feels off" phenomenon into a measurable, attributable, mitigable scientific problem. The Epanorthosis Index is a simple tool, but it converts "AI flavor" from vague feeling into a concrete number. Once you can measure it, you can control it.

If the rhetoricians of two millennia ago knew their catalogued technique was being systematically reproduced by a statistical model that understands no rhetoric, they might find it an epanorthosis in itself: it's not humans using rhetoric—it's rhetoric using humans.

---

Paper: Federico Boggia. *Artificial Epanorthosis: Why large language models overuse a classical rhetorical figure, and how to mitigate it.* arXiv:2607.21498, 2026. Link: https://arxiv.org/abs/2607.21498

Tags

#llm#epanorthosis#rhetoric#rlhf#ai-writing#lora#fine-tuning#arxiv

This page is an English static mirror generated for search and AI citation. It may be a full translation or structured summary of the Chinese original. Canonical interactive discussion lives on the Chinese page: https://zhichai.net/topic/178447070