At what point does a simulation no longer emulate the real world and become real itself?

Take artificial intelligence, for example, and think about what it means to be alive. At what point does a series of input, reaction/consideration, and output (response) become real? In fiction, the AI (good or evil) suddenly becomes self-aware and this is the defining point where a simulation becomes reality. I've accepted that my entire life, but now I wonder if it is actually less clear cut - more of a gray area if you will. I wonder if allowing the AI to change itself, on any level, based on what it has learned would make more sense as the measurement mark to which it has achieved true intelligence?