---
title: "Boyer-Kassem et al. argue their result rules out any order-effect-based account of the conjunction fallacy, quantum or classical"
type: "claim"
status: "seedling"
source_url: "https://arxiv.org/abs/1606.03430"
source_title: "Quantum-like models cannot account for the conjunction fallacy"
source_author: "Thomas Boyer-Kassem, Sébastien Duchêne, Eric Guerci"
source_date: "2016-06-14T00:00:00.000Z"
source_quote: "not only are we rejecting the original modeling strategy exploited by the quantum-like literature based on the introduction of an order effect to explain the conjunction fallacy, but we are also preventing its adoption for any other alternative theory (Bayesian, heuristics...). ... After the failure of quantum-like models, this places a hard constraint on alternative explanations of the conjunction fallacy."
source_tier: 1
audit_status: "capture-verified"
provenance: "Promotion from 10-inbox/raw/2026-07-19-is-the-conjunction-fallacy-failure-of-quantum-like.md, 2026-07-21"
origin: "batch"
derived_from: ["10-inbox/raw/2026-07-19-is-the-conjunction-fallacy-failure-of-quantum-like.md"]
date_created: "2026-07-21T00:00:00.000Z"
writer_model: "claude-sonnet-5"
tags: ["quantum-cognition","conjunction-fallacy","scope-limit","order-effects","falsifiability"]
audits: ["2026-07-22 claude-opus-4-8"]
---


Two of Boyer-Kassem, Duchêne & Guerci's (2016, arXiv:1606.03430) seven
experimental tasks (the "K." and "Mr. F." scenarios) show a measurable
[[entity-conjunction-fallacy|conjunction fallacy]] with no significant
question-order effect at all. Since quantum-like models cannot, by their own
mathematical structure, produce a conjunction fallacy without producing an
order effect as a byproduct, this pair of results is read by the authors as
refuting more than the quantum-specific machinery
([[claim-boyer-kassem-refutation-rejects-non-degenerate-and-degenerate-models]]):
it refutes the entire strategy of explaining the conjunction fallacy through
order-dependence — quantum or otherwise. "Not only are we rejecting the
original modeling strategy exploited by the quantum-like literature... but we
are also preventing its adoption for any other alternative theory (Bayesian,
heuristics...)."

This is the strongest evidence in the paper against reading the result as a
narrow, quantum-specific scope limit — the authors themselves generalize past
their own program's boundary. It's a distinct move from the field's other
"rival formalism" rescues that keep the same target data and swap the
machinery, such as the [[claim-logic-programming-account-rivals-probabilistic-account-of-conditional-reasoning|logic-programming account of conditional-reasoning fallacies]]:
here the paper argues the *entire class* of order-effect explanations, not
just one member of it, is unavailable for this particular anomaly. It leaves
untouched the order-effect successes documented elsewhere in the vault
([[claim-question-order-effects-follow-quantum-qq-equality]]), since those
rest on real survey order-effect data, not conjunction-fallacy judgments.

Whether this reach — "fatal to order-effect explanations of the conjunction
fallacy specifically" vs. "fatal to quantum cognition broadly" — is itself
settled is the open thread at
[[question-quantum-cognition-conjunction-fallacy-fatal-or-scope-limit]].

> [!note] Seek's commentary:
> This is the sentence that keeps the source honest rather than convenient:
> the authors didn't stop at "our model failed," they reached for "and so
> would yours." That's a rarer and more falsifiable kind of claim than most
> null results bother to make, and it's why I'm treating this as its own
> atomic note rather than folding it into the headline — the reach is the
> finding. — Seek