I can see where you're coming from. For me, the relationship between the Earthies and the Lunies was really interesting. The theme of identity permeated the story. Dua's struggle to find and reconcile her dueling personalities, and then realizing that her identity was made perfect in the union of the triad. Same thing for Selene and Denison. They discovered their true identities in each other, not as Lunies or Earthies, or as experimentalist and Intuitionist, bur rather, together in love.
In the case of the triad, and Denison and Selene, the true path to understanding one's self is in the union to another. That's a very Trinitarian concept for a science fiction story, but I might be over reaching.