I can believe a miracle because I can raise my own arm. I can believe a miracle because I can remember. I can believe it because I can speak and be understood by you.
The boy reached through to the Soul of the World, and saw that it was part of the Soul of God. And he saw that the Soul of God was his own soul. And that he, a boy, could perform miracles.
We buy books, we go to gyms, we expend a lot of brain power on trying to hold back time, when we should be celebrating the miracle of being here in this world.
The genuine realist, if he is an unbeliever, will always find strength and ability to disbelieve in the miraculous, and if he is confronted with a miracle as an irrefutable fact he would rather disbelieve his own senses than admit the miraculous also.