An evidence of the immortality of the human spirit is the fact that it is not affected by changes in the body. The body is subject to various conditions. At one time it may be healthy; at another time it may be susceptible to some pathology. At one time it may be weak or ill; at another time it may be well and strong; or a member may become lost. However, the reality within the body -- the human spirit or mind -- is the same. If the body should become lean the spirit would not become lean. If the body should become corpulent the spirit would not become corpulent. If the body should be dismembered the spirit would not be affected. In brief, the spirit is independent of the body, and the disintegrations that take place in the body do not affect the soul, for the human reality or spirit is ever the same.
(‘Abdu’l-Baha, excerpt from a talk at Theosophical Society, San Francisco, October 11, 1912; Unpublished Manuscript by Ella Cooper) (To read the entire talk please visit Talks of ‘Abdu’l-Baha)