Differentiation always entails the positing of phenomena i.e. is based on the isolated fixing of reference frames so that the positive (conscious) direction is thereby experienced.
However, as in dynamic (unconscious) terms the positive direction is balanced by the negative, this means that when the negative is not recognised it thereby becomes split off from the positive becoming repressed in the unconscious.
Thus in the most fundamental sense the positing of phenomena - though which differentiation takes place - always entails corresponding (unrecognised) negation which thereby becomes repressed and buried in the unconscious.
Putting it another way the rigid differentiation (i.e. positing) of phenomena - which is always associated with a corresponding degree of rigid attachment - equally implies rigid negation where the opposite pole is thereby unrecognised and repressed in the unconscious.
Thus before integration can properly take place the rigid (one-sided) positing of phenomena must cease.
This requires the explicit unfolding in experience of dynamic negation, which helps undo this rigid identification to one isolated pole at a time (thus eroding possessive attachment).
The capacity for this dynamic negation is itself dependent on growing spiritual awareness (where both poles are reconciled in awareness).
In spiritual terms it is referred to as purgation, purification (cleansing) of faculties, the dark night, knowing by unknowing etc.
When dynamic negation (i.e. purgation) is successfully undergone, a considerable lessening in rigid attachment to differentiated phenomena results. Because the positive pole is no longer posited in a rigid one-sided manner, greater fusion with the complementary negative pole is possible leading to a consequent deepening in (unconscious) spiritual awareness. This also leads to a lessening in repression with a greater facility to unearth hidden and unrecognised elements in the unconscious.
This in turn is associated with a significant growth in bi-directional understanding i.e. where every linear (asymmetrical) interpretation is understood to have a mirror image opposite explanation (which is equally valid).
Thus it is the continual reconciliation of these opposite explanations - which from a dualistic perspective are deeply paradoxical - that leads to a great growth in nondual spiritual awareness.
Though the problem relating to possessive attachment ultimately resides in the will with its desire for a limited form of good, it is always associated with a significant distortion in understanding. So one-sided (rigid) emphasis is placed on unambiguous dualistic notions of truth (i.e. defined in terms of isolated polar reference frames).
However because volitional and intellectual understanding necessarily interact, the attempt to remove such distortions (at an intellectual level) can significant assist the desire of the will for a purer spiritual experience of meaning.