> for interfaces (as if those were a different thing) Interfaces are a different thing than inheritance, precisely because of what we are talking about. Inher

> for interfaces (as if those were a different thing) Interfaces are a different thing than inheritance, precisely because of what we are talking about. Inheritance is about code re-use, and interfaces are about polymorphism. Interfaces are the polymorphism part of "inheritance", while dropping the code re-use part. It is true that composition does not give you polymorphism, absolutely. > because the only thing composition solves is code reuse. Exactly. Inheritance combines polymorphism and code re-use in one form. If you instead don't have inheritance, than interfaces (or something similar by a different name; or "duck-typing" if you don't have static typing and also don't really want any kind of typing at all) give you polymorphism, so what gives you code re-use? Composition. If you split the code re-use function from the inheritance function, interfaces plus composition is the (or one very common/obvious) solution. I don't think we are disagreeing, I mean to show you we are all violently agreeing. :)