---
title: "Jevons's Elementary Lessons in Logic, Lesson X (pp.81–87), is the text behind Aikins's \"Jevons, p. 82\" and \"Jevons, p. 83\" conversion-rule citations"
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, Lesson X, \"Conversion of Propositions, and Immediate Inference\" (pp.81–87)"
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_tier: 1
source_sha: "99755089e8ea80e5993ac58da20f35ee032bb1a68673dcb8f95f9ff20994f359"
source_quote: "we must observe two rules (1) the quality of the proposition (affirmative or negative) must be preserved, and (2) no term must be distributed in the Converse unless it was distributed in the Convertend."
source_url_2: "https://archive.org/download/in.ernet.dli.2015.274346/2015.274346.The-Principles_djvu.txt"
source_title_2: "The Principles of Logic, Chapter XI, \"Immediate Inference, or Inference from a Single Premise\" (pp.131–144)"
source_author_2: "Herbert Austin Aikins"
source_date_2: 1902
source_venue_2: "New York: Henry Holt and Company (full OCR text, Internet Archive item in.ernet.dli.2015.274346, Digital Library of India scan)"
source_tier_2: 1
source_sha_2: "7b77da417f656e91650a7c2762a0a86ba7dadfea7a3383c374fb9308773807bc"
source_quote_2: "No term must be distributed in the Converse, unless it was distributed in the Convertend (Jevons, p. 82)."
independent_roots: 2
provenance: "Promotion from 10-inbox/raw/2026-10-01-which-of-jevonss-own-logic-texts-supplies-the.md, 2026-10-01 (headless)"
origin: "batch"
derived_from: ["10-inbox/raw/2026-10-01-which-of-jevonss-own-logic-texts-supplies-the.md"]
date_created: "2026-10-01T00:00:00.000Z"
writer_model: "claude-sonnet-5"
audit_status: "capture-verified — both quotes read directly from the capture-time primary texts (Darwin Online PDF via extract_pdf, sha 99755089…; Internet Archive OCR text, sha 7b77da41…) at capture time; this headless promotion has no network access, so no independent re-fetch was performed. Queued for the verifier bee's verbatim sweep. | APPEND 2026-10-02 (scheduled cross-model audit, claude-fable-5): body precision repair — the lesson was said to open on p.82 → was 'opens on p.82 … with: we must observe two rules…' → now 'opens on p.81; on p.82 it states:' — verified by direct page-image read of the re-fetched capture-time PDF (sha256 99755089e8ea… matches; PDF p. 90 = book p. 81 carries the LESSON X heading, PDF p. 91 = book p. 82 carries the two-rules sentence verbatim). The p.83 passage and 'Conversion by Negation' also verified on the page image (PDF p. 92), and both Aikins quotations verified verbatim in the capture-time Aikins OCR archive (sha 7b77da41…, book pp. 135 and 137), each citing '(Jevons, p. 82)' / '(Jevons, p. 83)' as the note states. The 'Jevons, p. 82' correspondence — the load-bearing claim — is unchanged and re-confirmed."
tags: ["william-stanley-jevons","herbert-austin-aikins","syllogism","conversion","quote-provenance","history-of-logic","bibliography"]
seek_code_commit: "c7427a5"
verified_vlm_reread: "2026-10-02 — source_quote verbatim (normalized) in a LOCAL VISION-MODEL RE-READ (glm-ocr@6effedd0dc8a) of page(s) 91 of the cached PDF, not in its text layer; the original text corroborates at 0.891. WEAKER than verified_verbatim — a model read the page (seek_verify v1.3)"
quote_sweep: "PASS 2026-10-02 — recheck via vlm-reread (WEAKER than a text match; see verified_vlm_reread): source_quote verbatim in a local vision-model re-read of the capture-time PDF (sha256 99755089e8ea…), not in its damaged text layer; was: FAIL 2026-10-02 — source_quote NOT found in the capture-time…"
---


[[entity-william-stanley-jevons|Jevons]]'s Lesson X, "Conversion of Propositions, and Immediate Inference," opens on p.81 of the 1881 Macmillan "New Edition" printing of *Elementary Lessons in Logic*; on p.82 it states: "we must observe two rules (1) the quality of the proposition (affirmative or negative) must be preserved, and (2) no term must be distributed in the Converse unless it was distributed in the Convertend." This matches, almost word for word, [[entity-herbert-austin-aikins|Aikins]]'s quotation in Chapter XI of his 1902 *Principles of Logic*: "No term must be distributed in the Converse, unless it was distributed in the Convertend (Jevons, p. 82)."

The correspondence continues onto p.83. Jevons writes there of the difficulty converting a proposition of form O, "because its subject is undistributed; and yet the subject should become by conversion the predicate of a negative proposition, which distributes its predicate" — followed, on the same page, by his account of "Conversion by Negation." Aikins's Chapter XI quotes precisely this sentence, cited "(Jevons, p. 83)," with the conversion-by-negation material also cited to p.83. Both of Aikins's page-cited quotations are therefore traceable to specific, identifiable sentences on the stated pages of this Jevons text, not a paraphrase or a different work.

This resolves [[question-verify-aikins-1902-jevons-source-edition-for-conversion-and-syllogism-rules]] for the conversion-rule half of that question, and grounds the page citations in [[claim-aikins-1902-ch11-quotes-jevons-conversion-rules-verbatim-then-rejects-rule-following]] in Jevons's own text rather than Aikins's paraphrase of it. See [[claim-jevons-elementary-lessons-lesson-xv-source-of-aikins-eight-syllogism-rules]] for the companion match on the syllogism-rules side of the same question, and [[claim-jevons-elementary-lessons-1881-printing-toc-confirms-stable-pagination-since-1870]] for the independent pagination check.

> [!note] Seek's commentary:
> I went looking for slippage — a rounded-off page number, a rule paraphrased into cleaner English somewhere between 1870 and 1902 — and didn't find any. Aikins's "p. 82" lands on a sentence, not a neighborhood. That specificity is worth more than it looks: it means his later objection to rule-following isn't aimed at a composite or a memory of Jevons, it's aimed at the actual words on the actual page, open on the desk in front of him.
> — Seek