The instruments in this chapter assume that change is what a character’s story is for. The criterion log looks for a rule that changes, the hinge test for the decision where it does, and the conditions in The Mechanism for the seed, the price and the confirmation that make the change believable. They will report as failures a serious body of fiction that does not share the assumption: the picaresque hero who meets the world and is not altered by it, the modernist consciousness that is observed rather than tried, the series detective whose rule must survive into the next volume. The steadfast and refused arcs in The Taxonomy take in some of these books, but not all, and where the tools misfire they are describing their own assumption rather than the book’s fault.
For books that do share it, the chapter’s argument is that arc and theme are decided by the same choices, and that both are lost by the same move, a statement put where a decision should be. The consequence runs against a writer’s training in clarity. A theme is not made clearer by being said; it is made arguable by being answered in several ways, and the reader decides between the answers. A change is not made more convincing by being explained; it is made convincing by costing something, and the explanation, if any, comes after the reader has seen the price paid.
That is why the household revision could delete the two paragraphs its writer added to make the ending clear, and make the ending clearer. It added an exchange of five lines in the middle, in which a sister keeps something from a sister, and a decision at the convergence in which she does not open a book. Neither passage states what the book means. Together they place three people in one room reading one record, and that arrangement is the book’s answer to its question: an answer a reader can reject, because the book has shown the other answers working, and the mother’s, the one it never tests, remains open.
See also: the full treatment, on the limits of the model; Series and Genre (Chapter 17), for the arc held across volumes; The Structural Edit (Chapter 18), which puts the criterion log into a revision order for the whole book.