Well, separating computation into messages and methods and binding the message to the method at run time, based on the class of the receiver, may seem like a small change from an ordinary procedure call, but it is a small change that makes a big difference.
q: how oop makes big difference?
diff: message vs method:
Message(call in traditional oops languages) is what is being sent to the receiver. Method is what message gets binded to in the receiver.
