Q. This is a two-part question if you don’t mind. I’m editing academic writing and would like to (a) insert nouns when an adjective is being used alone, for example “Medievals think . . .” (I would prefer “Medieval philosophers think . . .”), and (b) insert “and” when an author left it out of a series, for example, “of discerning true from false, good from evil, just from unjust.” (I want to insert “and” before “just.”) Am I being too picky?
A. Yes, maybe a bit too picky. Neither construction is incorrect, and in (a) you risk changing the writer’s meaning by filling in the word you think she meant. If you think a phrase is unclear, press the writer for clarification. If the context makes the meaning obvious, however, I would respect the writer’s preference for brevity and variety. As for (b), such constructions can have a pleasing rhythm that would be wrecked by adding “and,” so use your ear before you meddle.