How do I stop a theme from turning into a sermon, in particular when characters state the theme in dialogue?

Baker identifies the thesis or problem play's characteristic fault as dialogue in which "the author himself is speaking", gives a worked example (Senator Morse speech) and a repair rule (rewrite until the speaker would say it). Archer says Brieux's theme-first plays suffer from "obtrusive predominance" of the abstract element and recommends openly declaring a moral apologue. Chekhov argues the writer should not judge, and that a sermon plus art is hard because maintaining the characters' tone is needed. Together: three fixes: voice the idea in the speaker's character, declare the fable, or withhold the verdict. These are literary-historical sources; no test of audience effect exists. Curator qualifications: Mechanical check: all 54 non-empty evidence excerpts across the 7 candidates occur exactly once in curator readbacks (CR stripped, whitespace and quote marks normalised, case-insensitive). Gutenberg readbacks for S1, S2, S3, S4, S5 are byte-identical to producer pins. Spot phrases: Baker 'the author himself is speaking' 1, 'Morse' 4; Archer 'obtrusive predominance' 1. Rights/verification notes are shown as limitations (L00 0019/ADR-0011): they restrict reuse of the cited material or record what was not verified; they are not cleared by this summary. Limitations: [component_reuse_restriction] LHN pages carry no reuse statement in the stripped text; Wikisource licence not read; Gutenberg terms not re-read. Evidence status: curator/producer inference or synthesis from the cited sources (code read, not executed, where code is cited); correlated desk review (Claude); not independently reviewed.

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      "note": "see curator disposition"
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