Different orders of Polymorphism

When most computer science texts refer to polymorphism (in the context of object oriented programming) they are referring to either refining the implementation of a method via subclasses overriding that method, OR, by defining more than one behavior (method) with the same name. The former case (hopefully) preserves the semantics of the method name, the latter overloads multiple semantics on the same name. In either case, it is only the method that is multifaceted, not the entire object much less the class hierarchy.

With Existential Programming, a different order of polymorphism (i.e. "a single entity can take on multiple forms") is at work. Here a single entity in its entirety can take on multiple forms. Heck, it can take on multiple ontologies (aka class hierarchies). This means either supporting multiple (albeit, fundamentally similar) views/conceptions of an entity, OR, trying to knit together very different models where the object instance is in some sort of oscillating Schrodinger's Cat-like state (except that we can look at it and not affect its state :-).