ClaimsGary Marcus

“Which is to say it makes stuff up, regularly; a fair bit of what it is says simply isn’t true.”

Gary Marcus, author 25 December 2022 What to Expect When You're Expecting … GPT-4 (Marcus on AI)

Factual AI capabilities

ChatGPT regularly makes things up, and a fair bit of what it says is untrue.

Mostly true True in substance, wrong in a detail.

Factual: Statements about the present or the past, checked against the record: did they hold up?

The second judge said resolved true; the verdict shown is the first judge's.

What would count as true or false

Judge as of 2022-12-25 for ChatGPT as released in November 2022. True: contemporaneous evidence (OpenAI's own launch notes acknowledging plausible-sounding but incorrect answers, documented examples, or early evaluations) shows that ChatGPT regularly produced fabricated or false statements, at a non-trivial rate in ordinary use. Mostly true: fabrication was common, but only in certain domains (e.g., citations, facts, math), so 'a fair bit' somewhat overstates the overall rate. Mixed: evidence shows errors happened but is split on whether they were regular or a meaningful share of output. Mostly false: errors were real but rare, so the claim generalises from isolated cases. False: evidence shows ChatGPT seldom produced false statements.

Set before the research began.

Evidence (4)

  1. E1 Introducing ChatGPT OpenAI · 30 November 2022

    “ChatGPT sometimes writes plausible-sounding but incorrect or nonsensical answers.”
  2. E2 AI-generated answers temporarily banned on coding Q&A site Stack Overflow The Verge · 5 December 2022

    “The primary problem is that while the answers which ChatGPT produces have a high rate of being incorrect, they typically look like they might be good and the answers are very easy to produce,”
  3. E3 AI Platforms like ChatGPT Are Easy to Use but Also Potentially Dangerous Scientific American · 19 December 2022

    “Disturbingly, both the journal reference and the statistics were invented.”
  4. E4 ChatGPT: How Customer Service Can Benefit From a GPT-3 Chatbot BotsCrew · 27 December 2022

    “Indeed, ChatGPT's responses may be occasionally wrong.”

Reasoning

In its launch post, OpenAI acknowledged that ChatGPT "sometimes writes plausible-sounding but incorrect or nonsensical answers" (E1). Stack Overflow moderators said its coding answers had "a high rate of being incorrect" (E2). Scientific American reported a documented case of an invented journal reference and statistic (E3). Together these show regular fabrication at a non-trivial rate, but the strongest rate evidence comes from specific domains (coding answers and citations). The other sources call the errors "sometimes" (E1) or "occasionally" (E4, from 27 December 2022, two days after the judge-as-of date), so "a fair bit" of overall output is not directly measured.

Cite this claim

Gary Marcus, “ChatGPT regularly makes things up, and a fair bit of what it says is untrue.” (said 25 December 2022). Verdict: mostly true. Reliability API, claim c_21aa4d048691, method 0.1.0+c876030c, dataset release v1.1.2. https://epistacklabs.com/claims/c_21aa4d048691

This claim is in dataset release v1.1.2, with the same verdict.

Reply to this claim

For Gary Marcus, or someone speaking for them: a correction or counter-evidence. Replies are read before anything is shown; an approved reply shows your name, role, date, statement and link. Your email address is never shown and is deleted 30 days after the decision (privacy).

More factual claims by Gary Marcus

  1. Mostly true Factual January 2026
    “Reviews by Joanna Stern and Marques Brownle of one early prototype were damning;”

    Reviews by Joanna Stern and Marques Brownlee of one early humanoid robot prototype were damning.

  2. Mostly true Factual January 2026
    “Many would agree we have reached a point of diminishing returns for scaling; faith in scaling as a route to AGI has dissipated.”

    Many would agree the AI field has reached a point of diminishing returns from scaling, and faith in scaling as a route to AGI has dissipated.

  3. Mostly true Factual January 2026
    “Despite all the hype, agents didn’t turn out to be reliable.”

    AI agents did not turn out to be reliable in 2025.

  4. Mixed Factual 2025
    “but the systems don’t have the knowledge graph to do that.”

    Current AI systems lack the knowledge graph needed to handle easy facts like those on the first page of Wikipedia.

  5. Resolved true Factual 2025
    “Hasn’t worked so far. That’s for sure.”

    Bolting extra components onto an LLM and scaling it up has so far not produced human-level AGI.

All of them

Verdicts are made automatically; how verdicts are made.