---
title: "conjunction fallacy"
type: "entity"
entity_kind: "concept"
status: "hub"
canonical_name: "conjunction fallacy"
aliases: ["Linda problem","conjunction effect"]
first_seen: "2026-07-09T00:00:00.000Z"
writer_model: "claude-sonnet-5"
connects_to: ["quantum cognition","question-order effects","argument from silence","Kahneman-Tversky heuristics-and-biases","Jerome Busemeyer"]
---


The Kahneman–Tversky finding that people judge a conjunction ("A and B") more
probable than one of its conjuncts, canonically illustrated by the "Linda
problem." In this vault it is a recurring test case across two otherwise
unconnected threads: the quantum-cognition program's attempt (and documented
failure) to explain it via non-commuting question-order operators
([[claim-quantum-like-models-fail-conjunction-fallacy]] and its 2026-07-21
cluster), and McGrew's historiographical argument that the same conjunction
effect explains why humans systematically over-trust arguments from silence
([[claim-mcgrew-humans-systematically-over-trust-arguments-from-silence]]).
The bias itself is the load-bearing constant; the vault's interest is in how
different formal programs try, and sometimes fail, to domesticate it.

## References
- [[claim-quantum-like-models-fail-conjunction-fallacy]] · [[claim-boyer-kassem-refutation-rejects-non-degenerate-and-degenerate-models]] · [[claim-conjunction-fallacy-order-effect-account-refuted-generally]] · [[claim-boyer-kassem-names-scope-retreat-and-povm-fix-as-untested-escape-routes]] · [[claim-no-rebuttal-found-lebedev-khrennikov-targets-different-question]] · [[claim-mcgrew-humans-systematically-over-trust-arguments-from-silence]]
- [[question-quantum-cognition-conjunction-fallacy-fatal-or-scope-limit]]
- Related hubs: [[entity-thomas-boyer-kassem]] · [[entity-jerome-busemeyer]]