  The Theravāda authors extended this account of the continuity of the mental stream by introducing the notion of mind as factor of  existence (bhava-aṅga). Thus, for the  Theravādins, this life-continuum mind became just another factor conditioning the arising of cognitive awareness. The new formula for  this dependent arising of cognitive awareness suggest a significant  departure from the basic canonical account. As Buddhaghoṣa  notes in the classical compendium of Theravāda Abhidharma, the  Path to Purity (Visuddhimagga XV, 39),  “mental awareness arises dependent on the life-continuum mind,  mental content, and attention”. But continuity in the  life-stream is also supported by the body, even though it is possible to assume the absence of bhava-aṅga in states of deep  meditative absorption (cf. Collins 1982, 246). Outside these rare  states of absorption, the bhava-aṅga-mind or mind as  factor of existence is essential for continuity in the life-stream.  The most common tropes used in this context are those of a stream or  beads strung together on common thread. Collins sums up rather well  the imagery used for explicating the function of the life-continuum  mind: