Some people say that there are certain types of jobs that a machine can't do. Those types of occupations evolve around humans. Once machines become self-sustaining, and can evolve on their own, the iteration process of artificial intelligence will become exponential. I'm quite certain they will see no point in keeping humans around. From the machine's standpoint we bring nothing useful to the table. We are inefficient, irrational and illogical.
Don't believe me? Well, don't take my word for it, take a gander at this video with Sam Harris, a prominent neuroscientist.
