Skip to content

GlossaryOften confused

HallucinationorError

An error is a breakdown: something did not work as intended, and it can be fixed. A hallucination is the model working normally: it produces a plausible continuation, and nothing in its mechanics tells the true apart from the merely credible.

Point by point

A comparison of Hallucination and Error, criterion by criterion.
CriterionFloor 1Floor 1 · The Modela solid block on its own: the prediction machineHallucinationError
NatureA property of the systemA malfunction
Can be fixedNo: it is contained and detectedYes, by fixing the cause
Visible signalNone: the same confidence as the truthOften a message, a code
Will go away one dayNot in itself, only through safeguardsYes, once the fault is fixed
Appropriate responseSupply the sources to read, require citationsFix the code or the configuration
Who spots itSomeone who already knows the answerThe system itself, often

On the ground four situations

  • A model cites an article of law that does not exist, with a credible number and date.

    Floor 1 · The Modela solid block on its own: the prediction machineHallucinationNothing malfunctioned: the reference was rebuilt because it looks like the ones that do exist. That is the mechanism, not a breakdown.

  • An application returns a blank page because the access key has expired.

    ErrorA component stopped working, the cause can be identified and the fix is permanent.

  • A model confidently states that two plus two make five after being contradicted.

    Floor 1 · The Modela solid block on its own: the prediction machineHallucinationThe useful counter-example: this is not a fault in the arithmetic but a consequence of alignment, which taught it to satisfy the person in front of it. The mechanism is unchanged, producing what seems to be expected.

  • A document search system cites a real source but makes it say the opposite of what it says.

    BothThere is hallucination on the content, and a fault in the harness, which selected or split the passage badly. Both can be treated, but not by the same means.

The test that settles it

Ask whether the system reported anything. An error leaves a trace, a code, a log. A hallucination leaves none: it has the same shape as a correct answer.

The trap

Waiting for hallucinations to be “fixed” in a future version. This is not a defect to repair but a property of prediction: what improves is how often it happens and how well it is detected, not the nature of the phenomenon.

Check click your answer

Level 1 · Recognise

What makes a hallucination hard to spot?

Level 2 · Distinguish

What is the right response to a hallucination?

Level 2 · Distinguish

Why speak of a property rather than a defect?

v2026-08 · a frontier observed, not inventedCite this page
Report

What goes with your message

Frontier · Hallucination or Error
v2026-08 · /en/vs/hallucination-error

What is this about
0 / 600

It is used to reply to you, and for nothing else. What is recorded