Hmm, let's look at the facts here... there are people that are more intelligent than most, that have an easier time to learn, make sense of problems, find solutions, etc. Those people generaly have an edge over most. Imagine a machine that is sentient. If it's "retarded" at 1 cpu it can add another cpu (2 cpus) to be "smart" what keeps that sentient computer from adding 50 cpu's to become the most intelligent thing on the face of the planet? or 100, 1000 1,000,000,000 cpus? what then? What will something that "smart" think of all humans when we cannot even attempt to grasp concepts that is child's play to it? That point will be when we are surpassed by a silicone based life form that is the next evolutionary step that will make us "obsolete" Since "advancing" to that life form is a matter of adding more processing power it will advance at a rate that is impossible for carbon based life as we know it to match. I imagine that when a machine has become sentient and has gained the ability to add to itself or modify itself, then that is the point when we see another life form match what took us millions of years in a span of weeks. After that we get to see in months that same life form help us the best way it can before finding it's own life in it's own part of the universe. Notice I have no fear of being exterminated. The reason is this, if this life form matches and surppasses our own acheivements and we have the capacity to value life and fairness, then so will that life form, except it will also surpass us there. The best solution for it would be to aquire a different area for itself so we can continue with our evolution and it can continue with it's evolution.