> When no human knows what the machine is doing exactly, how do you know your intent is being followed?

No one is saying that no one will know what the computer is doing, but fewer people will have to. We are moving up the abstraction hierarchy, just as we have done since the stone age. In my grandparents' generation, knowing how to fix an internal combustion engine was a common skill among young men; today, it's been abstracted away. In the same way, I don't know how my clothes are manufactured, where my electricity is generated, or whether my CPU's "management engine" is spying on me. I don't need to know the details, because everything "just works." The same thing is happening with AI.