[ddimitrov]

>> There's an interesting point to be made here, though - "wrapping everything up in one type" is essentially what dynamic type systems do, except that it's baked into the language instead of being implemented by the programmer on an as-needed basis.

This is imprecise - a dynamic language does not really need to "wrap everything in one type" - look at Dart or Groovy. What makes it 'dynamic' is the dynamic dispatch. All dynamic languages I know dispatch based on runtime argument types, but this is only one particular form of dynamic dispatch. Declaring types in dynamic language typically is used at runtime merely as an assertion, that at this point the argument must conform to the said type.

Dynamic dispatch differs from Polymorphic dispatch in the way that polymorphic dispatch takes in account the runtime type of the target (the object whose method you are calling), but the types of the parameters are fixed at compile time.

Many dynamic languages also provide a way to customize the dispatch logic (i.e. call a default handler if no match exists) - typically via some form of Meta Object Protocol. Often the dynamic languages provide features like higher order functions, continuations, pattern matching, etc. but this has nothing to do with their dynamicity - same features are available in some static languages as well.