It's unlikely that a single AI system or application could become powerful enough to conquer the world. No, AI won't take over the world. Movies like Me, Robot are science fiction, with an emphasis on the word fiction. The list of jobs that Artificial Intelligence will take on is extensive and includes tasks that were previously thought to be exclusively human, such as writing, journalism, graphic design and law.
Even jobs that require creativity and critical thinking are vulnerable to AI being done with control.
