# Conjunction fallacy

*Also called: Linda problem*

- **Cluster:** Evidence and sampling — The data that was gathered, and the data that was not
- **Page:** https://fallacy.wiki/fallacy/conjunction/
- **In Arabic:** https://fallacy.wiki/ar/fallacy/conjunction.md
- **Licence:** CC BY 4.0 — https://creativecommons.org/licenses/by/4.0/

## What it is

Judging a detailed, specific scenario as more likely than the broader one that contains it.

## In the wild

> She is more likely a banker who volunteers than just a banker.

## How to answer it

Remember that adding detail can only lower probability, never raise it.

## Origin and naming

Documented by Amos Tversky and Daniel Kahneman in 1983 through the 'Linda problem': told that Linda is bright and outspoken, most people rated 'Linda is a bank teller and feminist' as more likely than 'Linda is a bank teller'. The finding held even with statistics students, which is what made it famous.

## More places it shows up

- A jury thinks it more likely the defendant 'planned the fraud and covered it up' than just that he 'planned the fraud' — the second story is more damning but strictly less probable.
- An investor judges 'the startup will succeed because it rides the AI wave with a brilliant team' as more plausible than 'the startup will succeed'.
- A football commentator says the striker is 'more likely to score and celebrate toward the ultras' than just 'more likely to score'.
- A dating profile reader concludes a match is 'more likely a surgeon who rescues stray cats' than just 'a surgeon'.

## How to spot it

- Adding detail makes the story feel truer — that feeling is exactly the trap. Probability does not reward narrative richness.
- The conjunction always contains one 'representative' element that fits the description you were given, and that fit is doing all the work.
- If you strip the extra clause out and the claim feels suddenly blander, you were sold a story, not a probability.

## Nearby

- [Base rate neglect](https://fallacy.wiki/fallacy/base-rate.md)
- [Texas sharpshooter](https://fallacy.wiki/fallacy/texas-sharpshooter.md)

## Read more

- [Wikipedia](https://en.wikipedia.org/wiki/Conjunction_fallacy)
- [The Fallacy Files](https://www.fallacyfiles.org/conjunct.html)

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From fallacy.wiki — a bilingual field guide to 91 logical fallacies, published by phi holdings. Licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/): reuse freely with attribution to fallacy.wiki.