The irony of religious upbringing
One institutes a child into a religious upbringing with the hopes of giving that child a happier, more morally competent life, but this novel explores the adverse and ironic effects that often arise instead. Because of a chronic contrast between "real" life and their insulated cult indoctrination, these young women swing into dramatic young adulthoods where they each reverse the effects of religion, one intentionally, and one through lengthy reckonings.
Kate's ironical similarity to Baba
Kate is the one who resists chaos more. Baba is comfortable with chaos naturally, so when Baba leaves religious boarding school, she is unscathed. She hates religious authority structures the same way she hates all imposed kinds of order. Kate, on the other hand, has created a nice like house for herself in the sand. Her identity is rooted on a cognitive dissonance that is shaky at best; she acts like she wants to be married and in love, but really, she wants permission to be sexual. Baba helps show that irony by encouraging her to have sex with a series of single men in London.
The pain of delusion
Kate is riddled by delusion. It is not so much that she forgot she lied to herself; it is actually more like she created a schism between two mutually-exclusive, yet still true versions of herself. When she's diving into bed with the sexy men of London, she is not any less "Kate," than when she is keeping her virginity for "the one." The truth is that Baba has aspects of Kate's character, and vice versa. The real ethical punishment comes when Kate makes decisions based on delusional points of view.
Eugene as an irony
Eugene is a perfect example of what is ironic about Kate's endeavors. Eugene is a serial monogamist. To someone like Kate, there is just enough evidence of attraction and chemistry for Kate to spiral off into absolute delusions about Eugene's intentions. Of course he doesn't want to settle down and marry her—one look at his friend group would show that plainly. But Kate's character has a hubris that demands tragic reckoning; she pretends to be more morally good than she is because she feels ashamed of her own sexuality. She uses hubris as a defense mechanism against her own desire to have sex.
Sexual shame and paradox irony
The motif of sexual shame is common enough that the tone of the novel is essentially a commentary on this irony. Shame leads to an experience of reality that is ironical paradoxical and counter-intuitive. Baba's sense for moral goodness is not rooted in shame, so secretly Kate thinks less of her. This dramatic irony is chronic, but eventually Baba catches on that deep down, Kate thinks less of herself when she acts like Baba. Secretly, shame makes Kate judgmental and deeply hypocritical, with religious hypocrisy—the most unsavory kind of all.
