..The basic structure of al-Ghazali's thought places God and His essential attributes of Will and Knowledge at the basis of all phenomena. This universe has two aspects: there is the natural physical world subdued to God's Will, called Mulk / 'Wordly-Dominion'; and a heavenly realm termed Malakut / 'Spiritual-Kingdom'. The Mulk is merely the shadow of the true realm of spiritual existence. Abu Hamid states: "the bodily world has no real existence, but is in relation to the 'World of Divine-Order' (alam al-amr) like the shadow of a body; the shadow of a man is not the real substance of that man, and so the individual being is not really existent but is a shadow of the real substance (in `Arba'in). Likewise, the human is basically composed of two aspects: the body and the spirit interpenetrating one another. The body is the 'riding-animal' for the spirit (ruh). The essential reality of the human lies in the spirit, also termed nafs "soul", qalb "heart", or 'aql "mind-intelligence".
http://www.ghazali.org/articles/heart-mind-kdc.htm