Aikins's 1902 Preface states, before any chapter begins, that his deductive-logic treatment deliberately omits 'the traditional rules of the syllogism' in favor of his own stated 'principles'

jingle-fallacyherbert-austin-aikinswilliam-stanley-jevonssyllogismhistory-of-logic

The Preface (p.iv) of Aikins's The Principles of Logic (1902) sets out, in his own words, the program his later syllogism-rule chapters instantiate: "Consequently I have omitted the traditional rules of the syllogism and put in their place a direct statement of the principles on which we reason in the different figures, adding certain 'cautions' that must be observed if the principles are not to be misapplied; and I have treated conversion and obversion in much the same way" (quoted here in corrected reading; the capture's OCR renders "statement" as ".statement", "must be observed" as "mu.st be ob.served", and "and I" as "anil 1" — the frontmatter source_quote preserves the OCR bytes verbatim, per the 2026-10-01 audit repair).

This is a programmatic, book-opening statement of correction and replacement, made before Aikins reaches the jingle-fallacy material in Chapter XVIII (see claim-aikins-1902-proposes-jingle-fallacies-as-class-name-in-chapter-xviii). It establishes that displacing the rule-based tradition — of which Jevons is Aikins's named representative in Chapter XI's conversion material and Chapter XVI's syllogism-figure material — is the organizing project of the deductive half of the book, not an incidental byproduct of the fallacy chapter written six chapters later.

Together, the Preface and the two chapter-level engagements answer a question the vault had left open since 2026-09-18: Aikins's own syllogism-rule chapters do correct and contest Jevons's stated rules directly and in his own words, independent of, and prior to, the shared jingle-fallacy chapter the vault had already captured.