> In naive OO examples (Animal -> Cat) it does. An inheritance hierarchy consists of three things: a taxonomy, behavioural inheritance and structural inheritan

> In naive OO examples (Animal -> Cat) it does. An inheritance hierarchy consists of three things: a taxonomy, behavioural inheritance and structural inheritance. The first is only useful on occasion, and the last two don't even apply to Animal → Cat; "animal" is not a behavioural constraint, and a cat certainly doesn't have a platonic ideal of an animal hidden somewhere inside its gut.