You don’t understand. As Dmitri said, this Katya is in love with her own virtue. That sort of love is cold, and it will break a man. Far better the insect’s sting of sensuality! That’s what moves a man. Remember what he said: “I am that very insect, brother…and all of us Karamazovs are like that, and in you, an angel. The same insect lives and stirs up storms in your blood. Storms, because sensuality is a storm, more than a storm! Beauty is a fearful and terrible thing! Fearful because it’s un-definable, and it cannot be defined, because here God gave us only riddles. Here the shores converge, here all contradictions live together. I’m a very uneducated man, brother, but I’ve thought about it a lot. So terribly many mysteries! Too many riddles oppress man on earth. Solve them if you can without getting your feet wet. Beauty! Besides, I can’t bear it that some man, even with a lofty heart and the highest mind, should start from the ideal of the Madonna and end with the ideal of Sodom. It’s even more fearful when someone who already has the ideal of Sodom in his soul does not deny the ideal of the Madonna either, and his heart burns with it, verily, verily burns…No, man is broad, even too broad, I would narrow him down. Devil knows even what to make of him; that’s the thing! What’s shame for the mind is beauty all over for the heart. Can there be beauty in Sodom? Believe me, for the vast majority of people, that’s just where beauty lies – did you know that secret? The terrible thing is that beauty is not only fearful but also mysterious. Here the devil is struggling with God, and the battlefield is the human heart” (108).
Here’s how it seems to me: Katya is beautiful to Dmitri at first because of the contradiction in her soul. She is an institute girl who will sell herself to a man! The devil struggles with God. But Katya’s beauty fades when she fails to see her own contradictions. She loses Dmitri precisely because she hates the contradictions in her nature and seeks to conceal them behind the roles of sister and saint. What do you think of that theory?