Whereas Quotes - page 31
Denying miracles, the Teacher pointed out the concealed powers of human nature which, when developed, can produce the so-called miracles.
The method of developing these powers is interpreted in Buddhist books and is known under the name of the science "Iddhi-Vidhanana,” which points out two forms of manifestation of these powers and two ways to attain them. One, the lower, is reached by way of various ascetic and other physical practices; the other higher one, embracing all possible manifestations, is attained by the power of inner development. The first method of developing these powers is not lasting and may be lost, whereas inner development can never be lost. Its mastery is attained by following the noble way indicated by Buddha. All these hidden powers gradually unfold in man, usually of themselves, in proportion to man's mastery of the lower expressions of his nature in a whole series of previous lives.
Helena Roerich