Earlier quoted context omitted.
With Objective-C, that will always come back "true." Even if you never use dynamic lookups, Apple's frameworks do. I suspect the same is true of other languages.
Interesting, I find that surprising due to the overhead involved. In most languages calling functions via string names is very expensive. PS: Do you have an example?
Due to the frequency of this, objc_msgSend (which handles dynamic method calls) is hand-written in assembly, with caching and "fast paths" to improve speed. The overhead can usually be brought down to that of a virtual function call in C++.