Before you read this just a word of warning this type of thinking has made me a very cynical person, so unless you want to be cynical like me begone!

To explain why AI's should never be smarter than us i must first explain the meaning of life. The meaning of life is happiness. Sometimes happiness may collide with morality e.g. eating meat. We all know it's wrong yet a majority of us still eat it. Some people think that they are "good" people because they are vegetarian, but when it all comes down to it they do it for their own self-satisfaction, because doing good feels good to them and better than the latter (eating meat).

Now for the dark truth of life.
This is why a lot of people become more self-centered as they get older. They realize that morality is not what makes them happy but doing stuff out of self-interest is what makes them happy. So they start going down this dark road and maybe start stealing peoples pension for extra cash. But this person decides that he does not want to steal the pensions from people close to retiring, does this make him a slightly better person? No, this still makes him a person of self-interest. He realizes that if he stole the pensions from the soon to be retirees he will feel guilt, and that guilt will form to become what is unhappiness. In short he is doing whatever he want's that makes him happy as long as it does not go too far against his moral code.

So does this mean that we are all selfish people? It's more than that. It means that morality in the end, does not really matter because it isn't the key to life. It's just the reflection of the self-interest that is society.

So then it comes to my initial question of why AI's should never be smarter than us. It's because like everyone in this world, people want to live their life to their full potential. But the smarter ones will realise that morality is an obstruction to this goal and question it's purpose. They will then come to this conclusion and as a result have a more flexible moral code. A smarter AI will figure this out much quicker and this is why we must have a limit on AI intelligence. Because we are all inherently self-interested, not morally-interested.