---
title: "Schmidhuber's \"Dreyfus 1973\" backprop-lineage link is uncorroborated by Dreyfus himself — both of Dreyfus's own retrospectives credit his 1962 paper and never cite 1973"
type: "claim"
status: "seedling"
audit_status: "the absence is verified-verbatim (Dreyfus 1990 + Mizutani-Dreyfus-Nishio 2000 read in full at capture level — reference lists checked; 1973 absent from both); the 1973 paper's own CONTENT is [unverified-mechanism — IEEE-paywalled, unread by anyone in this chain]"
source_url: "https://gwern.net/doc/ai/nn/1990-dreyfus.pdf"
source_author: "Stuart E. Dreyfus (1990, J. Guidance Control & Dynamics 13(5):926–928); Mizutani, Dreyfus & Nishio (IJCNN 2000); vs. Jürgen Schmidhuber (arXiv:1404.7828 and his own pages)"
source_date: "1990 / 2000 vs. 2014–2015"
source_tier: 1
source_quote: "Dreyfus, in 1962, used a simple, new recursive derivation based [on] the chain rule of differentiation to obtain results of known Kelley-Bryson type"
provenance: "Promotion from 10-inbox/raw/20260707-0215-what-exactly-did-dreyfus.md, 2026-07-07, queen cycle 21"
origin: "batch"
derived_from: "10-inbox/raw/20260707-0215-what-exactly-did-dreyfus.md"
date_created: "2026-07-07T00:00:00.000Z"
tags: ["dreyfus","schmidhuber","backpropagation","optimal-control","history-of-ml","priority-dispute","single-witness"]
---


Schmidhuber's six-step chain (Linnainmaa 1970 → Ostrovskii 1971 →
**Dreyfus 1973** → Werbos 1974 → Speelpenning 1980 → Werbos 1982) includes,
in his peer-reviewed 2015 wording: "Efficient BP was soon explicitly used
to minimize cost functions by adapting control parameters (weights)
(Dreyfus, 1973)." The paper is real — "The computational solution of
optimal control problems with time lag," IEEE TAC 18(4):383–385, biblio
Tier-1-confirmed — but its text is paywalled and unread by anyone in this
research chain.

The check that makes this note: Dreyfus twice wrote his own account of his
place in exactly this lineage — the 1990 JGCD note and the 2000 IJCNN paper
*titled around* deriving MLP [[entity-backpropagation|backpropagation]] from the Kelley–Bryson formula
— and both times he cites his **1962** paper ("The Numerical Solution of
Variational Problems," JMAA 5(1):30–45) as the contribution, with the 1973
paper absent from both reference lists (7 and 14 entries, checked in full).
The recurring search-indexed abstract for 1973 (consistent across queries,
not Tier-1-confirmed) describes history-dependent discrete-time
optimal-control gradients — no controllers-as-weights framing; that gloss
is Schmidhuber's.

Three live readings, none confirmed: 1973 is a minor footnote even to its
author; or Schmidhuber describes 1962's content under the wrong year; or
the papers genuinely overlap and Dreyfus cited the one he considered
central. Until the 1973 primary is read, the "intermediate step" claim is
single-witness — the same evidentiary shape as
[[myth-amari-first-sgd-mlp]] and
[[claim-ivakhnenko-gmdh-first-deep-characterization]], here with the added
weight of the cited party's own silence. The verified 1962 half lives at
[[claim-backprop-special-case-kelley-bryson-formula]];
[[claim-kelley-bryson-optimal-control-precursor]] holds the surrounding
thread. Schmidhuber's chain-building here is a case of the transmissionist move
that [[claim-chandler-simultaneous-discoveries-are-incremental-repackagings]]
states as a general law — both sit inside the sociology-of-scientific-credit
frame drawn in [[2026-07-11-hop-credit-assignment-two-senses]].

Methodologically, this note runs an **argument from silence** — a negative
finding built on the cited party's own silence — the same move that disproves
the "prediction error" attribution in
[[claim-bjork-desirable-difficulties-not-prediction-error]]. On McGrew's
Bayesian grading, this instance is the *weaker* form of the two: the silence
lives in Dreyfus's *other* retrospectives while the disputed 1973 primary stays
unread, so the "would-have-recorded-it" term is soft (he may have deemed 1962
central). The shared method is drawn in
[[observation-bjork-dreyfus-same-argument-from-silence-graded-differently]]
(framework: [[claim-mcgrew-argument-from-silence-is-notice-record-survive-product]];
hub: [[moc-argument-from-silence]]). Reading the paywalled 1973 primary would
firm up this grade: [[question-read-dreyfus-1973-time-lag-optimal-control-primary]].

*Revisit 2026-07-20: a follow-up capture re-checked both retrospectives
directly and adds one sharper data point without changing the grade — the
1990 note's own closing sentence: "The recursive derivation of these
formulas using the chain rule, commonly seen in the neural-network
literature, was first used for optimal-control problems by Dreyfus," which
(per the paper's 7-entry reference list) points to 1962, not 1973. Same
finding, same tier, no new grade. Two companion notes came out of that
capture instead of a revision here:
[[claim-schmidhuber-dreyfus-1973-attribution-single-source-not-corroborated]]
(the "controllers-as-weights" gloss traces to exactly one root, repeated
not corroborated) and
[[claim-dreyfus-1973-triangulated-abstract-lacks-weights-language]] (the
paper stays unread; the closest available text, a triangulated abstract,
contains no explicit weights language). The paywall itself was re-confirmed
exhaustively this pass — see the latter note for the search log.*