  Now, in the canonical literature consciousness  (vijñāna) is treated as a synonym of apperception  (saṃjñā) [see Sutta Nipata, 538,  806]. This lack of clear dissociation between apperception,  understood here as the empirical apprehension of phenomena, and  consciousness as the apprehending faculty, is made obvious by  frequent references to saṃjñā as being the  cause of attachment to agreeable physical objects and mental states.  Furthermore, apperception is often contrasted with wisdom thus  suggesting that what is meant by it is not sensory activity proper  but rather the awareness that bears upon it. Likewise,  vijñāna does not denote consciousness as a  cognitive phenomenon distinct from sense perception. Rather, it  refers to the consciousness of a specific sense modality (e.g.,  visual-awareness, auditory-awareness). Because the mental faculty is  also regarded as a sensory system, the type of awareness that bears  upon it is termed mental or ‘introspective awareness’  (manovijñāna). The arising of consciousness, thus, depends on sense perception, but it also depends on attention, since  sensory activity alone does not give rise to perception. The latter  activity requires attending to the stimuli: the amorphous mass of the sense data gives rise to a percept only when sensation is coupled  with attention. In the formula of dependent arising that we encounter at several places in the canonical literature, consciousness is said  to arise in dependence upon the sense and the physical object. But  the appearance of phenomena itself depend in turn upon this empirical awareness. Thus, the Buddha declares: