Human Prose

Human prose

Write for a reader who processes one clause at a time. Each rule below removes a documented processing cost. The evidence base with full citations is references/evidence.md; load it only when a rule is questioned or amended, or when a full citation must be quoted.

The rules

1. One idea per sentence, kept short. Comprehension falls as sentence length rises (Flesch 1948). Split rather than subordinate.
2. No mid-sentence interruptions. An em-dash aside or a nested parenthetical suspends a clause the reader must hold open (Gibson 1998). Write a second sentence instead. A short parenthetical label (like this one) is fine; a clause-length intrusion is not.
3. Active voice; verbs over nominalizations. Passives verify slower than actives (Gough 1965). Nominalized prose reads worse than its active-verb form (Coleman 1964).
4. Given before new. Open each sentence from material the reader already has, then add the new (Haviland & Clark 1974). No inverted openings ("Nor was X a one-off").
5. No decorative emphasis. Emphasis works by selectivity (Schneider et al. 2018). Flourishes are seductive details, and those measurably hurt learning (Rey 2012). One signal per scope, chosen deliberately.
6. Plain register. Jargon appears at most once, as a parenthetical label on the plain phrase it names. (User rule, 2026-08-01: write in plain language.)
7. Name the referent. An abstract noun standing for something else in the document ("this cost", "that discipline", "the price") makes the reader search for what it names, and they resolve it against the nearest candidate rather than the intended one (Haviland & Clark 1974). Write the thing itself, and say where to look at it. (User rule, 2026-08-02, after a paragraph built from four such nouns was reported as unintelligible.)
8. Say it once, then stop. Length is a cost the reader pays whether or not the words earn it. Cut restatements, preambles, hedges, and sentences that announce what the next sentence will do. A sentence that survives deletion without loss should be deleted. (User rule, 2026-08-03: be verbose only when necessary, and only when the extra words carry genuinely useful information.)

The pass

Apply the rules as a dedicated pass after the content is complete, not while drafting. Rule 8 goes first: cut whole paragraphs before polishing sentences, or the pass polishes text that should not exist. Keep verbatim material untouched: quotes, compiler error text, signatures, citations. In Lean files, verify afterwards that the diagnostic set is unchanged; in Lean files all commentary goes in /- ... -/ blocks, never -- line comments.