The true mechanism of social cohesion is neither love nor hate, but knowledge. The greater at least two individuals know each other’s personalities, the greater the bond between them. This seems to be the case, even where the operative emotions within the circle, are predominately negative: hence the “love-hate” relationship.
“Knowledge” comes the same root as “gnosis”, of course. Knowing is a part of any social relationship. There is no relationship, if one does not know another. Indeed, the limits of any community are measured by how well each member knows the others — and how much they share knowledge in common about the outside world.
Social knowledge is essential to human society, because of the inherent limitations of self-knowledge, the inability of a knower to totally know him- or herself. Here the shared roots of “knows” and “gnosis” are most evident. The bond of knowledge that holds people together is, to a great extent, ineffable. It is understood, but cannot be fully explained. Social knowledge is “subjective”, where emotion and intuition are intertwined with abstraction. But the faculty of abstraction was totally essentially to hominid evolution, just because of the need for the members of the tribe to know one another.
The evolutionary theorist Will Calvin calculated that human brain capacity would have to expanded, from the time of the “Lucy” primate two-and-a-half million years ago, by a third of a percent each millennium, to reach size of the brain of the modern human. Language was the articulation of knowledge, which was in turn objectified in writing. The latter permitted the separation of abstraction from emotion, and other subjective states, in regard to the acquisition of knowledge. With applied knowledge, the living environment has become so engineered, that people do not know their neighbours.