Identity is Scale
Identity is a question of scale.
X can be -Y as X with both as Z and neither as -Z.
There is opposition degree of difference, while the harmony is the containment of the contrast that allows identity to occur.
The difference of X and -Y can be observed as X and -Y while the absence of difference is the synthesis as Z and the absence of either is -Z.
Identity becomes emergence scale the relation of contexts themselves.