Is Heart of Darkness AI-generated? 1 of 7 AI detectors said yes
Heart of Darkness is Joseph Conrad's 1899 novel, and almost no detector thought otherwise. Only 1 of 7 free AI detectors flagged its opening as AI-generated, and that was TMR, which flagged every human fiction passage in our main test. Fakespot gave the passage a 0.7% AI probability and Desklib 0.1%. Fast-DetectGPT and MAGE passed it as well.
Tested
What each AI detector said
| Detector | Verdict | AI probability |
|---|---|---|
| Fast-DetectGPT (Qwen2.5-1.5B) | Human | raw score only |
| Desklib AI text detector | Human | 0.1% |
| Fakespot AI text detector | Human | 0.7% |
| MAGE | Human | raw score only |
| E5-small LoRA detector | Human | 34.9% |
| OpenAI RoBERTa detector | Human | 0.0% |
| TMR (Target Mining RoBERTa) | AI-generated | 97.3% |
The passage we tested
The Nellie, a cruising yawl, swung to her anchor without a flutter of the sails, and was at rest. The flood had made, the wind was nearly calm, and being bound down the river, the only thing for it was to come to and wait for the turn of the tide. The sea-reach of the Thames stretched before us like...
Only TMR flagged it
TMR called the opening of Heart of Darkness AI-generated at a 97.3% AI probability, and no other detector agreed. Fakespot put it at 0.7%, Desklib at 0.1%, the OpenAI RoBERTa detector at 0.0% and E5-small LoRA at 34.9%, and MAGE and Fast-DetectGPT both passed it.
The TMR verdict says little about Conrad. TMR flagged all 24 human fiction passages in our main test and 83.3% of human texts overall, and our test with paragraph breaks removed showed that line breaks drive most of its AI calls. The Conrad passage has four paragraphs.
Why a famous novel can still pass
Heart of Darkness is a famous, much-reprinted novel too, so familiarity alone does not seem to decide the result. What the opening has is a strange, dense way with words. The sea and the sky are “welded together without a joint”, the barges carry “gleams of varnished sprits”, the gloom over London is “brooding motionless”, and the Accountant is “toying architecturally with the bones”. There is sailing jargon too: a yawl, the flood that “had made”, a mizzen-mast.
A language model would rarely guess any of those phrases. Fast-DetectGPT flags text whose words a model finds predictable, so Conrad’s choices are a likely reason it passed this passage while flagging other famous novel openings such as Dracula. The trained classifiers probably react to something similar, since AI-written fiction tends to reach for more familiar images than these.
Fiction with unusual language
For anyone writing fiction with unusual, specific language, these results are mildly reassuring. Desklib, Fakespot and the OpenAI RoBERTa detector gave Conrad AI probabilities of 0.7% or less, and Desklib and Fast-DetectGPT flagged none of the human fiction in our main test. TMR is the exception, and a TMR flag on a story with paragraphs should be ignored. Read the TMR results for the details, or compare all 30 texts on the famous texts page.
Questions people ask
Do AI detectors think Heart of Darkness was written by AI?
Almost none do. TMR flagged it at a 97.3% AI probability, but TMR flags nearly all fiction with paragraph breaks. Desklib, Fakespot, E5-small LoRA, MAGE, Fast-DetectGPT and the OpenAI RoBERTa detector all called it human.
What makes Conrad's prose look human to detectors?
Probably its unusual word choices. Conrad describes the sea and sky as "welded together without a joint" and a man "toying architecturally with the bones" of a domino set. Language models are unlikely to predict phrases like these, and unpredictability is what several detectors read as human.