Rice's theorem

Rice's theorem states that for any non-trivial property of the behavior of computer programs—meaning any characteristic that some programs have and others don't—it’s impossible to create a universal method that always determines whether a given program possesses that property. In other words, no general algorithm can reliably decide how programs behave regarding such properties, making it fundamentally undecidable to automate certain kinds of program analysis. This underscores the inherent limitations in predicting or analyzing program behavior in a complete and automatic manner, especially when the properties relate to the program's output or function.