The symbolism of the premise
The premise of this novel is that an elderly woman is given a last confession of the unadmitted sins of her life, so that the book takes on a moralistic feel. This is an allegorical response to the threat of death, not only to the human body but to the human soul. There is something about dying which makes this life-time author and artist, Iris, want to confess the secret truths which always underpinned her art. The premise symbolizes the curious psychological reflections that death brings up as a meditation; as she contemplates her death, she wants to make a full admission about her life.
Art as a symbol
This novel is meta-narrative because the author writes about an author who write about an author. That means that within the artistic substance of the material, parallels can be drawn to the real process of creative the narrative itself. That means art itself can be treated as a symbol in the book. The use of art in the book is an expression of sacred pains which—like the scandalous affairs of the novel—are socially unacceptable to mention, but are acceptable in art. Art here is seen as a place of truth beyond what is socially acceptable.
The husband rapist
Eventually, Iris realizes that her husband is a serial rapist who has made a victim of her own sister. That horror is symbolic, because it allows Iris a chance to truly admit the depth of her husband's evil and corrupt character. That is an experience that breaks innocence, just like the sins of her husband take innocence away from women whom he molests or rapes. She is symbolically connected to his evil by marriage, which means that her despising of him is held in tension with her sacred oath to love and forgive him. He is a symbol for human malice and evil.
The single mother motif
The motif of the single mother is so incredibly packed full of meaning that one might say it is a transcendental principle. In this universe, life exists because beings can beget other beings, so in response to the experience of her husband's evil, this archetypal artist-hero escapes his domain to live alone as a single mother. Together, they form a portrait of how earth operates; she sacrifices tremendously to give her child an opportunity to have a good life, putting her own life as a lower priority. That symbolizes love as a response to evil and human suffering, just like the Madonna and Christ motif.
The affair
The symbolic scandal of this novel is that this bereaved and confused wife whose husband is angry and aloof, secretly hiding sexual sins against her own sister, explored other relationships besides her relationship to her tyrannical husband. The scandal is that she found love in a forbidden place, making the affair into a symbol. Where does the artistic meaning and beauty of Iris's artwork stem from? As the premise suggests, it stems from her admission of "sin," participating in what is forbidden. The morality of her life is symbolically called into question. Perhaps a defense could be made for her in essay.
