Actually, no matter the achievements of people, they are really very humble. Consider a quadriplegic. There isn't any known way that he can think his body back into proper operation. And if there is brain damage, he might not be able to think at all.
If we hadn't been given our bodies and minds for free, we couldn't get them by our own exertion. Sure, we can strengthen them and improve them somewhat. But there are limits to this. Try growing a second set of arms below the ones you already have. If you can do it, you are the only one.