To me, what's interesting with this subdivision is how it allows for incomplete rhetoric, arguments that engage or achieve less than all four ends. Campbell looks at it linearly, but I don't think that's necessarily the case. Moving someone without informing or pleasing them in particular--you get the results, but it's not in a necessarily lasting way. St. Augustine (I will never stop citing Augustine) warned against oration that gains applause, but doesn't move the listeners' hearts towards the right end.