One is increasing complexity. The other is increasing miniaturization. Put together the progression of life is existence of increasingly greater complexity in increasingly smaller packages. Paolo Soleri sees the city as the physical form of the social structure of humanity. In his view, equity is a uniquely human construct, while congruence is a state of being implicit in nature.
Equity is something that has grown out of the human capacity to do wrong.
Congruence is a measure of balance. In the context of the social, it is the balance between humans and the environment, something that can only be achieved through global equity and coherence of will. Humans cannot exist congruent to nature without equity, and equity cannot exist without congruence, since incongruence will destroy equity through imbalance. The only way, in his view, to ensure equity and congruence is through miniaturization, or creating the city in the image of man. This means creating an urban form that is congruent with humans and not with their machines.