Miracles can be defined as
"Surprising acts or happenings that can't be explained by law of nature. They are the extra ordinary or unusual things in nature." Fortheringay himself describes miracles as
"Something contrawise to the course of nature by power of will something which could not happed without being specially willed." Thus, he tells that the central power of performing miracles is nothing but will power. It was will power with Fortheringay could perform miracles. At the end, when he willed to lose powers, he immediately lost it.