Why method invocation in Objective-C called message passing?

Question

Is it like if I "pass a message" between two objects and if they happened to be have been instantiated in different threads then the invoked method would still run in its object's thread?

Answer 1

Calling a method is resolved at compile time and the method can be expected to be present at run time. Message passing is resolved at run time and the receiver object does not need to understand how to handle the message.

The term "message passing" in Objective-C does not have anything to do with threading.

I found a good article about this topic here: http://iskren.info/reading/info/ObjC/reading/dynamite.html