You mean those "subtheoretical languages" with "practical aspects" like deciding whether to use an abstract base class, which allows implementation inheritance

You mean those "subtheoretical languages" with "practical aspects" like deciding whether to use an abstract base class, which allows implementation inheritance for friends but violates encapsulation; or putting static final methods in an interface and using reflection to dynamically dispatch via a meta-object protocol to the contra-variant constructors of a private inner class? All languages and paradigms can be obscure to outsiders. Just take a look at http://programmers.stackexchange.com/questions/tagged/object-oriented http://programmers.stackexchange.com/questions/tagged/object...