Novelist: Any author who thinks a sentence is ungrammatical will not write it down in the first place, and thus will have no need to use a grammar book. On the other hand, any author who is sure a sentence she or he has written is grammatical will not feel a need to consult a grammar book. Thus, grammar books are useless as reference sources for authors. The reasoning in the novelist's argument is flawed because the argument ['presumes, without providing justification, that grammar books cannot have any use except as reference sources', 'infers, from the claim that an author does not mistakenly think that a sentence is ungrammatical, that the author will feel sure that it is grammatical', 'ignores the possibility that there is a middle ground between being sure that a sentence is grammatical and thinking that it is ungrammatical', 'infers, from the claim that authors should not consult grammar books, that they will not in fact do so']