Spelling irregularities where there was no obviously preferred version were left as is. Variants include: "cotemporary" and "contemporary;" "commonplaces" and "common-places;" "dependents" and "dependants;" "dreamed" and "dreamt;" derivatives of "enclose" and "inclose;" "e. g." and "e.g."; "i. e." and "i.e."; "misestimate" and "mis-estimate;" "recal" and "recall" (and derivatives); derivatives of "paraphrase" and "periphrase;" "subclass" and "sub-class" (and derivatives).

Volume I. contains "το ὄν," while Volume II. spells it "τὸ ὄν." The spellings were left as is, in each case.

Changed "Phemomena" to "Phenomena" on page xv: "Successions of Social Phenomena."

Changed page reference for section 4 of Chapter XI on page xv of the Table of Contents from "539" to "540."

Changed "oberved" to "observed" on page 17: "the observed facts."

A closing double quotation mark is missing on page 17. It was added after the sentence that ends with "object of the inquiry."

Changed "neverthless" to "nevertheless" on page 104: "phenomena would nevertheless."

For the mathematical formulas appearing on pages 152 and 153: parentheses were added to make the linear form of the formula correct. The equal sign was preserved in "arc (sin = x)," although it makes more sense without it.

Page 240 contains the word "'Squire." It intentionally begins with an apostrophe, not an unmatched single quotation mark, and was left as originally printed.

Changed "eupiditatibus" to "cupiditatibus" on page 401: "de cupiditatibus finiendis." And shortly thereafter, changed "eupiditas" to "cupiditas:" "An potest cupiditas finiri." And then a bit further on, changed "hæe" to "hæc:" "hæc desideria naturæ."