Aren't subtypes just your type adapting to situation in which the assistance of one function is required more than the other function?
If that is true, then doesn't that mean that subtypes don't actually exists?
If you are mostly faced with situations demanding one function more than the other, then you use one function more than the other. But if suddenly, you are faced with a situation demanding assistance of the other function, then you use that function more.
What do you think?