This is essentially the approach taken by functional languages (they also include ways to collect functions into logical units). Object-oriented programming is

This is essentially the approach taken by functional languages (they also include ways to collect functions into logical units). Object-oriented programming is all about mutating the state of an object with private methods, though, so I think the author is trying to make his OO programming style look / feel more functional. If you're still convinced that OO and mutable state are a good idea, read this essay by the author of Clojure, it might change your mind: http://clojure.org/state http://clojure.org/state