Gary Marcus Causal claim First said 2023-02-03

“A subtler problem that I emphasized in 2001, an inability to keep track of knowledge of instances independently of kinds, seems to underlie the rampant hallucinations that allow large language models to say things like “Elon Musk died in a car crash in 2018”, even when nothing in the corpus says so, and massive amounts of data contradict the claim, because they blend together information about kinds with information about specific individuals, in haphazard ways.”

Happy Groundhog Day, The AI Edition, paragraph 5. The full statement is at the source.

Our reading, the sentence that was checked:

LLM hallucinations appear to stem from an inability to track knowledge about individual instances separately from kinds, so the models blend the two haphazardly.

Assessment: Can’t be checked Not checked against evidence

Where and when Gary Marcus wrote it

Marcus on AI, Happy Groundhog Day, The AI Edition, paragraph 5.

Said: 2023-02-03
Source observed: 2026-10-29live page, full text, public
Evidence: Not checkedboth screens found it cannot be checked
Assessment recorded: 2026-10-29assessment marcus-happy-groundhog-day-the-ai-edition-fc0e37-a1

We recorded 12 claims from this post. See every claim from this post.

The wording above is the version this site observed on 2026-10-29. The source may have been edited after 2023-02-03. This page does not claim the wording was captured then.

What the claim commits to

Kind: Causal claim
Deadline, as the speaker wrote it: None stated. This site does not add one.
Deadline state when assessed: No horizon
Deadline state on 2026-10-29: No horizon (the release’s reference date)

From the speaker

Nothing beyond the statement itself.

Our interpretation

None added.

This claim is not graded on evidence. The record checks that the words are quoted correctly and attributed to the right person, and that the claim is classified correctly.

Current assessment

Not graded on evidence

Outcome: Can’t be checked

Both AI providers screened this claim on their own and found that public evidence could not settle it. It is recorded and attributed, not scored.

Why it can’t be checked

Both screens gave the same reason:

Stated as a chance or a possibility, or at medium or low confidence.

Evidence: Not checked
Deadline state when assessed: No horizon
Assessment recorded: 2026-10-29
Policy version: 2026-10-28.7

Rationale

Not checked against evidence. Two independent screens, one from each provider, both found this stated as a chance or a possibility, or at medium or low confidence.

Limitations

None recorded.

Evidence (0 items)

No evidence was searched for. Both screens found that public evidence could not settle this claim.

This claim was not checked against evidence. claude-opus-5-5 (Anthropic) extracted it from the post and wrote the sentence at the top, our reading of the claim. claude-opus-5-5 (Anthropic) and gpt-6-astra (OpenAI) then screened it independently, without seeing each other’s answers. Both confirmed that the sentence says what the author said, and both found that public evidence could not settle the claim. No model wrote the assessment: code composed its text from the two screens, so there was no separate check of the final text. Code, not a model, decided whether it could be published.

Agreement between models is a check on the record, not proof that the assessment is right. Anthropic and OpenAI make these models, and some claims on this site are about those companies. How the method works.

Where it was said (1)

Said once in the sources this register covers.

2023-02-03: Marcus on AI, Happy Groundhog Day, The AI Edition
A subtler problem that I emphasized in 2001, an inability to keep track of knowledge of instances independently of kinds, seems to underlie the rampant hallucinations that allow large language models to say things like “Elon Musk died in a car crash in 2018”, even when nothing in the corpus says so, and massive amounts of data contradict the claim, because they blend together information about kinds with information about specific individuals, in haphazard ways.
Where
paragraph 5
Published
2023-02-03
Source observed
2026-10-29, live page
Access
full text, public

History

Assessment versions

Assessment marcus-happy-groundhog-day-the-ai-edition-fc0e37-a1: Current. Outcome: Can’t be checked. Not checked against evidence. Public date not recorded.

Recorded events

2026-10-29
Assessment publishedBy this site
First assessment published after both reviews and the final-text check passed.
About assessment marcus-happy-groundhog-day-the-ai-edition-fc0e37-a1.