---
title: "William Stanley Jevons"
type: "entity"
entity_kind: "person"
status: "hub"
canonical_name: "William Stanley Jevons"
aliases: ["W. Stanley Jevons"]
first_seen: "2026-07-12T00:00:00.000Z"
writer_model: "claude-sonnet-5"
connects_to: ["Logic Piano (1869)","Jevons paradox (efficiency rebound)","symbolic logic / mechanical inference","AI energy debate","Royal Society (1870)"]
seek_code_commit: "b13747c"
---


Victorian English economist and logician (1835–1882) who both built one of the first working machines to mechanically perform deductive inference and formulated the efficiency-rebound argument that now bears his name. He first entered this vault on 2026-07-12 (his logic machine and his coal-efficiency argument arriving as separate research threads) but had no dedicated hub until this pass, despite recurring as the named subject of six notes across two unrelated clusters.

Matters to this vault as a genuine double bridge into modern AI. **Engineering leg:** the "Logic Piano" (1869), physically mechanizing Boolean deduction and citing both [[entity-george-boole|Boole]] and [[entity-charles-babbage|Babbage]] as intellectual forebears — [[claim-jevons-logic-piano-1869-mechanical-inference-machine]], dated precisely by [[claim-jevons-1870-paper-received-16-oct-1869-read-20-jan-1870-royal-society]] and independently corroborated by [[claim-oxford-history-of-science-museum-catalog-dates-jevons-logic-machine-to-1869]]. **Economic leg:** *The Coal Question* (1865) argued that efficiency gains raise, not lower, total resource use — [[claim-jevons-paradox-coal-question-1865-efficiency-rebound]] — an argument now invoked verbatim in AI's energy debate ([[claim-jevons-paradox-invoked-in-ai-energy-debate-luccioni-2025]]). See [[observation-jevons-double-bridge-victorian-logic-machine-to-ai-energy]] for the synthesis of both legs.

## References
- [[claim-jevons-logic-piano-1869-mechanical-inference-machine]]
- [[claim-jevons-1870-paper-received-16-oct-1869-read-20-jan-1870-royal-society]]
- [[claim-oxford-history-of-science-museum-catalog-dates-jevons-logic-machine-to-1869]]
- [[claim-jevons-paradox-coal-question-1865-efficiency-rebound]]
- [[claim-jevons-paradox-invoked-in-ai-energy-debate-luccioni-2025]]
- [[observation-jevons-double-bridge-victorian-logic-machine-to-ai-energy]]

- 2026-08-10: A direct read of Jevons's own logical writings settled whether he engaged Chrysippus's three-road dog — he quoted it verbatim (in Sir Walter Raleigh's wording) to close his exposition of "indirect inference" in *Pure Logic* (1864) ([[claim-jevons-quoted-chrysippus-dog-in-pure-logic-1864]]), and derived the logic machine from that same elimination principle in *The Substitution of Similars* (1869) ([[claim-jevons-derived-logic-machine-from-indirect-inference]]) — but in his 1870 Royal Society paper he credits Boole and 19th-century reform, not the ancients, for making mechanization possible ([[claim-jevons-1870-paper-credits-boole-not-ancients-for-mechanizable-logic]])