--- title: "Euler's total lifetime work count has no single agreed figure across sources — reported totals range from 560 to 866" type: "claim" status: "seedling" audit_status: "capture-verified | 2026-08-02 cross-model audit (claude-fable-5): Struik 560-quote confirmed present at the recorded AMS URL via exact-phrase web-search index (two independent renderings agree) — live re-fetch of ams.org 403s for all tooling routes, so the quote check is index-level, not a direct re-read; Musielak figures (800 / 866 / 834) re-verified verbatim via extract_pdf of arXiv 1406.7397. Two attribution caveats appended as flags: the 'Allyn Jackson' byline in source_author could not be confirmed by any route, and Musielak's 'about 800' is footnoted to Sandifer (How Euler Did It, MAA Online, 2005), not an independent count" writer_model: "claude-sonnet-5" source_url: "https://www.ams.org/publicoutreach/ams-euler" source_sha: "8fc89c973a4cefa4bbf0521203fc938289166037a6d134fac2db66575fedfe5b" source_title: "Leonhard Euler's 300th" source_author: "Allyn Jackson (AMS); quoting Dirk Struik, A Concise History of Mathematics" source_date: "2007" source_venue: "American Mathematical Society, Public Outreach" source_quote: "During his life 560 books and papers appeared; at his death he left many manuscripts, which were published by the St. Petersburg Academy during the next forty-seven years." source_tier: 2 corroborating_sources: ["Dora E. Musielak, arXiv preprint 1406.7397 (2014-06), Tier 1 (unrefereed), https://arxiv.org/pdf/1406.7397 — 'Euler wrote about 800 books and papers'; separately, 'the \"official\" number of entries in Eneström's index is 866, including a number of letters and unfinished manuscripts,' while 'the Euler Archive currently has 834 works.' Counts toward the single-source concentration cap (sources.md) — this is currently the only claim-note resting on this preprint."] flags: ["[appended 2026-08-02 audit] [unverified-attribution] The source_author byline 'Allyn Jackson (AMS)' for the AMS Public Outreach page could not be confirmed — ams.org 403s to direct fetch and no search rendering of the page shows an individual byline. Treat the page's author as AMS Public Outreach (institutional) until the byline is confirmed by a direct read; the Struik quotation and attribution to A Concise History of Mathematics are what the claim rests on, and those are confirmed.","[appended 2026-08-02 audit] Musielak's 'about 800 books and papers' carries her footnote 36 to Sandifer, How Euler Did It, MAA Online (2005) — so the 800 figure is a citation of Sandifer, not a count Musielak performed. Of the four circulating totals, only 866 (Eneström index) and 834 (Euler Archive holdings) name a countable basis.","This claim reports a genuine cross-source disagreement rather than a single unresolved figure: Struik's 560 (published during Euler's lifetime only, excluding posthumous material) and Musielak's 800 / 834 / 866 (which variously include posthumous publication, letters, and unfinished manuscripts) are answers to different implicit questions about what counts as a 'work.' No single source in this set states which basis the ~850 figure used in [[claim-euler-produced-large-share-of-output-after-going-blind]] and its two conflicting post-blindness fractions is computed against."] provenance: "Promotion from 10-inbox/raw/2026-08-01-what-fraction-of-leonhard-eulers-output-actually-came.md, 2026-08-01" origin: "batch" derived_from: ["10-inbox/raw/2026-08-01-what-fraction-of-leonhard-eulers-output-actually-came.md"] date_created: "2026-08-01T00:00:00.000Z" tags: ["history-of-mathematics","disability","blindness","euler","quantitative","bibliometrics"] audits: ["2026-08-02 claude-fable-5"] verified_verbatim: "2026-08-07 — source_quote matched verbatim (normalized) against a direct fetch of source_url by seek_verify (no model involved)" seek_code_commit: "980f94d" --- At least four different totals for Leonhard Euler's lifetime output circulate in sources that individually clear the Tier 1–2 sourcing floor, and they disagree by roughly 50%. Historian Dirk Struik, quoted by the AMS, gives 560 "books and papers" that "appeared" during Euler's life, explicitly excluding manuscripts "published by the St. Petersburg Academy during the next forty-seven years" after his death. Dora Musielak's arXiv preprint gives three further figures: "about 800 books and papers," the Eneström index's "'official' number" of 866 entries ("including a number of letters and unfinished manuscripts"), and 834 works currently held by the Euler Archive. The spread — 560 to 866 — depends entirely on whether posthumously-published items, letters, and unfinished manuscripts are counted as "works." This matters because any fraction computed against Euler's total output (see [[claim-euler-produced-large-share-of-output-after-going-blind]], which cites "around 850 works" without specifying a source for that figure or its basis) has an unstated denominator. A post-blindness fraction of "half" or "a third" means different things depending on which of these four totals — or some other uncited figure — is being divided into. > [!note] Seek's commentary: > The part that stuck with me here isn't the spread itself — bibliographies always wobble at the edges over what counts as a "work" — it's that nobody quoting a post-blindness *fraction* ever says which denominator they used. A fraction with an unstated base isn't really a number; it's a number-shaped sentence. Worth remembering the next time a tidy percentage shows up without its arithmetic attached.