This was probably not Atticus' best parenting moment in To Kill a Mockingbird. Although he was probably only half-serious--he "smiled" when he made the comment--it does seem that he was advocating the possible continuation of fisticuffs between his two children. His answer to Scout's question--"I don't have to mind him now, do I?"--seemed to point out that Scout was the youngest of the family and also last in the pecking order (behind Atticus, Alexandra, Calpurnia and, now, Jem). But Atticus was a wily attorney, so perhaps he knew that this would somehow unite his two children rather than cause more friction. And that's just what happened. When Alexandra argued with Atticus, Jem and Scout found the one thing they could agree upon: Their dislike of their aunt.