arth (solidity), liquid, heat, and wind (motion). Three of them–liquid, heat, & wind–are potentially active. When they are aggravated, agitated, or provoked–the Pali term here, pakuppati, is used also on the psychological level, where it means angered or upset–they act as the underlying cause for natural activity. When the provocation ends, the corresponding activity subsides. Although §44 lists two nibbṅna properties, these two properties are distinctive in that the experience of nibbṅna is not caused by their provocation. Because true release is not caused by the provocation of anything–a fact that is known immediately after the experience itself–it is not subject to change. - --> - - - -