  An inevitable outcome of this dual aspect view of perception is the  tendency of most Buddhist philosophy of mind toward metaphysical  idealism, since the diversity and manifoldness of the perceived world suggest not a rich and variegated ontology, but a profligate mind.  Alternatively, the Buddhist philosophy of mind could be interpreted  as a type of phenomenology, since it argues that empirical awareness  opens us to a world that is not entirely free from our own mental  propensities (see   §5.4  and   §6.3).  It is primarily on account of this proliferating tendency of the  ordinary mind that notions such as self and other are superimposed  upon the constant flow of phenomena. Such superimpositions are the  main cause for the reification of perceptual content, leading to the  all too familiar propensity to operate with notions such as existence and non-existence, self and other. As the Abhidharma traditions  maintain, concepts are superimposed upon the constant flow of  phenomena in dependence upon the presence or absence of stimuli at  the sense-doors.