William Stanley Jevons is a double bridge from Victorian science to modern AI: the same polymath built an early mechanical logic machine and coined the efficiency-rebound paradox now framing AI's energy appetite

A hop chain that began at Peirce's typology of logical inference terminated on a single Victorian polymath, William Stanley Jevons (1835–1882), who turns out to anchor two independent threads running into modern AI — an unusually clean cross-time double bridge.

Leg one — the logic machine. Jevons built the "Logic Piano" (1869), an early machine that mechanically performed deductive inference (claim-jevons-logic-piano-1869-mechanical-inference-machine). It inspired Allan Marquand's logic machine, and it was to Marquand that Peirce proposed building such devices from electrical switching circuits in 1886 — placing Jevons near the head of the proto-computer / inference-engine lineage the vault tracks under claim-inference-classic-ai-engines.

Leg two — the efficiency paradox. The same man, in The Coal Question (1865), argued that efficiency gains raise rather than lower total resource use (claim-jevons-paradox-coal-question-1865-efficiency-rebound). That argument is now invoked verbatim in AI's energy debate: Luccioni, Strubell & Crawford (FAccT 2025) use it to argue that more-efficient models may consume more total energy, not less (claim-jevons-paradox-invoked-in-ai-energy-debate-luccioni-2025).

The observation is that these are not two people or two coincidences but one polymath sitting at the root of both the hardware ancestry of computing and the economic law now used to explain why more-efficient AI chips may burn more total energy. The vault already held both endpoints separately — the inference-engine / logic-machine cluster on one side, and the economics-of-compute cluster (including MONIAC and the grid-load and GPU-power notes) on the other. Jevons links them through one biography.