 Because according to Wundt’s principle of “actuality [Aktualität]” consciousness is purely an activity, it is impossible to render his theory in terms of “structures”. It consists in constantly interacting processes: on the one hand, there are associative processes that fuse sensations into elemental representations. These stream into and thereby constitute a fluctuating field of attention: flowing and broad, it is called “perception;” ebbing and concentrate, “apperception”. As an activity, attention is an expression of will; since consciousness just is attention in its shifting forms, it is the activity of will manifested in the selection, combination, and separation of disposable representations (PP II: 564). These representations are constantly “worked over” by apperception, which through its synthetic and diaeretic activity constructs them into ever “higher developmental forms of consciousness”, such that in the end their origins in sensation and perception might be completely erased. In other words, as the apperceptive activity becomes increasingly intense it seems as it were to rise above the field of perception, above the field of its own constructs, becoming aware of itself as pure activity, as pure self-consciousness: