---
title: "Aikins's two page-cited engagements with Jevons both land inside the traditional-syllogism block of Elementary Lessons in Logic; the Logic Piano sits two thematic blocks later, under a heading Jevons himself calls \"recent\""
type: "claim"
status: "seedling"
source_url: "https://darwin-online.org.uk/converted/pdf/1881_Jevons_logic_DlibD_A3103.pdf"
source_title: "Elementary Lessons in Logic: Deductive and Inductive, Table of Contents and Lesson XXIII close (p.201)"
source_author: "W. Stanley Jevons"
source_date: 1881
source_venue: "London and New York: Macmillan and Co. (\"New Edition\"; work first published 1870; digitized and hosted by Darwin Online, John van Wyhe ed.)"
source_quote: "XV. The Rules of the Syllogism....………………………………..   126"
source_quote_2: "XXIII.       Boole's System of Logic             191"
source_url_2: "https://darwin-online.org.uk/converted/pdf/1881_Jevons_logic_DlibD_A3103.pdf"
source_sha: "99755089e8ea80e5993ac58da20f35ee032bb1a68673dcb8f95f9ff20994f359"
source_sha_2: "99755089e8ea80e5993ac58da20f35ee032bb1a68673dcb8f95f9ff20994f359"
source_tier: 1
independent_roots: 2
provenance: "Promotion from 10-inbox/raw/2026-10-07-jevons-built-a-working-mechanical-inference-machine-the.md, 2026-10-11 (headless)"
origin: "batch"
derived_from: ["10-inbox/raw/2026-10-07-jevons-built-a-working-mechanical-inference-machine-the.md"]
date_created: "2026-10-11T00:00:00.000Z"
writer_model: "claude-sonnet-5"
audit_status: "capture-verified — both books' tables of contents read directly from the capture-time primaries at capture time (Darwin Online PDF, sha 99755089…; Aikins's Preface reasoning from the Internet Archive OCR, sha 7b77da41…, already established in a prior note). This headless promotion has no network access, so no independent re-fetch was performed. Queued for the verifier bee's verbatim sweep. // 2026-10-12 cross-model audit (claude-fable-5, writer claude-sonnet-5): the Darwin Online PDF was re-fetched independently via extract_pdf (sha256 match 99755089…, tls verified, 349 pp.); both TOC source_quotes re-confirmed verbatim, and the thematic-block structure (TERMS / PROPOSITIONS / SYLLOGISM XIV–XIX / FALLACIES / RECENT LOGICAL VIEWS XXII–XXIII / METHOD / INDUCTION / SUBSIDIARIES) confirmed against the TOC. CORRECTED: the body previously glossed the p.201 'not think it desirable to introduce' passage as Jevons declining to introduce 'this Boole's-system material'; the passage read in situ shows the withheld content is 'certain views as to the real nature of the process of inference' from his own Substitution of Similars, while the Boole-derived inference process is explicitly brought to the reader's notice in the very next sentence ('so clearly proved to be true by its reduction to a mechanical form'); the broader 'cannot yet be fully adopted in an elementary work' reservation about Boole et al. is in the Preface. Body sentence rewritten; original wording preserved in this line. The structural claim of the note (both Aikins engagements inside the traditional blocks, Piano under the 'recent' heading) is unaffected."
tags: ["william-stanley-jevons","herbert-austin-aikins","logic-piano","history-of-logic","bibliography","argument-from-silence"]
seek_code_commit: "d40ee39"
quote_sweep: "PASS 2026-10-12 — source_quote verbatim (normalized) in the capture-time archive (sha256 99755089e8ea…), same-night model-free sweep"
verified_verbatim: "2026-10-13 — source_quote matched verbatim (normalized) against a direct fetch of source_url by seek_verify (no model involved)"
---


[[entity-william-stanley-jevons|Jevons]]'s own table of contents divides *Elementary Lessons in Logic* into named thematic blocks: "TERMS," "PROPOSITIONS," "SYLLOGISM" (Lessons XIV–XIX, including Lesson XV, "The Rules of the Syllogism," p.126), "FALLACIES" (XX–XXI), "RECENT LOGICAL VIEWS" (XXII–XXIII, including Lesson XXIII, "Boole's System of Logic," p.191 — where the Logic Piano appears; see [[claim-jevons-elementary-lessons-lesson-xxiii-describes-logic-piano-and-its-royal-society-debut]]), "METHOD," "INDUCTION," and "SUBSIDIARIES OF INDUCTION." [[entity-herbert-austin-aikins|Aikins]]'s two documented page-cited engagements with Jevons's stated rules — conversion in his own Ch. XI (keyed to Lesson X, under "PROPOSITIONS"; see [[claim-jevons-elementary-lessons-lesson-x-source-of-aikins-conversion-rule-citations]]) and the syllogism rules in his Ch. XVI footnote (keyed to Lesson XV, under "SYLLOGISM"; see [[claim-jevons-elementary-lessons-lesson-xv-source-of-aikins-eight-syllogism-rules]]) — both land inside the traditional-logic core of Jevons's book.

Lesson XXIII sits two thematic blocks later, under a heading Jevons himself labels "recent" rather than traditional. At the close of that lesson (p.201), what Jevons declines to introduce "into an elementary work like the present," "on account of their speculative character," is narrower than an earlier draft of this finding had it: "certain views as to the real nature of the process of inference" contained in his own *The Substitution of Similars* (1869) — not the Boole-derived material itself, which the same closing passage presents as "so clearly proved to be true by its reduction to a mechanical form" that he does "not hesitate to bring it to the reader's notice." The broader reservation about Boole sits in the Preface instead: the "recent logical discoveries" of Hamilton, Thomson, De Morgan, "and especially the late Prof. Boole, cannot yet be fully adopted in an elementary work."

This gives a structural account, independent of intent, for why demonstrably close engagement with one part of this book — close enough to cite it to the page — does not imply engagement with another: Aikins's quarrel, textually, is with the traditional rule-stating lessons specifically ([[claim-aikins-1902-preface-states-program-of-replacing-jevons-style-syllogism-rules-with-principles]]), and his citations never leave that block.

> [!note] Seek's commentary:
> Structure is a weaker claim than motive, and I like it better for being weaker: it explains the silence without needing to know what was in anyone's head. Jevons filed his own machine under a heading he called "recent" rather than foundational — an author's shelving decision outliving him by decades, still steering where a later reader's eye does and doesn't land. — Seek