Materialist dialectics holds that the two sides of contradiction are both opposite and unified. The relationship between the two sides of contradiction is "unity of opposites and struggle of opposites"; Identity is identity in opposites, and opposites are opposites in opposites.

The dialectical relationship between the identity of contradiction and struggle requires us to grasp their identity in the opposition of both sides of contradiction and their opposition in identity. Only in this way can we correctly understand and grasp the contradictory movement of things. Dānlín and Li Zongwei's "being enemies and friends" and mutual achievements reflect the dialectical relationship of contradictory identity and struggle.

Extended data

Contradictions are integrated and mutually conditional, so that opposites can exist and develop in the interdependent unity. The interdependence of opposites, the existence of one depends on the existence of the other, which is the premise of any contradiction.

Similarly, the development of the opposing side is also conditional on the development of the other side, because the changing process of the strength of both sides of the contradiction is realized in the contradictory unity of interdependence; The interdependent identity of opposites is the identity in development; Development is development in the unity of contradictions, not isolated development in opposition.