The entire chapter is about how crucial relationships are to our awareness and consciousness. The last stage, Interdependence, is about allowing and celebrating the diversity in unity, or the unity in diversity, much like in Scott Pecks' development from pseudocommunity into full-fledged community where everyone is allowed to be who they are.
The four stages:
"Dependence: In this stage similarities are stressed. Couples experience this as their initial stage of being 'in love'. They feel euphoric because they see themselves in the mirror of the other person. Culturally this manifests as tribal life where the individual is expected to behave in a certain way in exchange for the tribe's support.
Co-dependence: Some individuality is expressed, but there is still a strong desire to identify with each other and no one steps too far out of 'the box.' Many tribal members in North America are in this stage, where they live in the city, but retain strong ties of dependence with the tribe.
Independence: In personal interaction each individual becomes almost desperate to find his or her own identity. Differences now are emphasized. In the modern, mechanized societies all types of insurance are needed since there is no tribal support. In apartments people live without knowing their neighbor's name.
Interdependence: If stage 3 can be survived, this stage brings stability. The individuals are secure in their relationships and supportive of each others' differences. This is the template for communal living for the future: a group lives together because of a common goal, voluntarily commits certain contributions and is free to express and grow in diversity."
Other quotes I resonated with:
"These stages lead from uniformity to unity within diversity."
"Tribal societies that remain in sameness are painfully pushed into change. Diversity produces more chances of exploring the unknown."
"In the stage of unity within diversity [interdependence] the chances are maximized for individual growth to contribute to the growth of the group within a stable environment."
You can download a copy of this chapter Alchemy of Relationship, by Almine, here.