It is regrettable that Dostoevsky did not more often include Nastasya in The Idiot's middle sections. Without a doubt, she is the novel's most dramatic and most complex character; it is she who steers the course of this novel and the fate of Prince Myshkin and Rogozhin. Structurally, perhaps, Dostoevsky neglected Nastasya to show us Myshkin's attempt at living among the bourgeois — as completely a failure as his experiences with such extraordinary types as Nastasya and Rogozhin. But even when Nastasya is absent from the action of the novel, her presence is felt; this is particularly true of the novel's beginning. Long before Nastasya Filippovna makes an entrance and we see her in action, we listen to Lebedyev's gossip about her; we hear Rogozhin's confession concerning his ungovernable passion for her that drove him to steal enough money to buy her a set of expensive earrings; the photograph of her is described, as is Myshkin's reaction to it; we witness General Epanchin's anxiety concerning Nastasya's decision to marry Ganya Ivolgin; and, we watch Ganya scheme, and the Epanchin women fume in jealousy, when Nastasya's name is mentioned. Nastasya is this novel's pivot.
Nastasya Filippovna has been extraordinary — singled out — ever since she was twelve years old and Totsky saw her, by accident. Earlier he had placed the young orphan girl with a good German family and, later, discerned a promise of unusual beauty in the young adolescent. Totsky educated her, was lavish with his money and created a well-bred, intelligent mistress for himself.
Halfway through her long liaison with Totsky, however, Nastasya demanded that he not dispose of her; she threatened him if he should ever marry, and thus Nastasya could no longer place the entire burden of shame on Totsky for her being a kept woman.
No one in The Idiot can understand Nastasya Filippovna's abrupt changes of mood and perhaps we should not attempt too narrow a formula for her motivations. Nastasya is highly emotional, full of guilt, out for revenge — things which cannot be logically equated into a cause-effect relationship. We have a full account of Nastasya's background and from that, and seeing that Nastasya's passion is extreme, we have to accept her actions and not, logically, try to find reasons for her capriciousness.
One of the best ways to understand Nastasya's actions is to imagine her desperate situation. She cannot continue as Totsky's mistress; the pose has grown tiring. She cannot marry Ganya, who lusts after her money and has threatened to mistreat her. Most of all, she cannot marry the innocent Prince Myshkin, who insists to her — and to other people — that Nastasya is not what she seems, that she is more kind and sweet than her haughty demeanor seems to indicate. Nastasya is far more objective about herself than either Myshkin or Rogozhin; the former sees suffering beauty in her eyes and so colors the whole of her character; the latter sees sensuous beauty and is spellbound. It is Nastasya's liability that she is so extraordinarily beautiful; men think of her only in terms of sex — and the money necessary for the luxury.
After Nastasya leaves Totsky, her only weapon for survival in the world of Petersburg society is her pride. She fled in the night with Rogozhin because of her insecurity; Totsky reared her to be a cultured accessory and she is adrift on her own. She realizes that, socially, she is at a dead end. And she is intelligent enough to rise above the ridiculous situation and see Myshkin as a saint, Rogozhin as a sensualist, and the rest of the men who flock around her as greedy and slavish. She sees an absurd morality play with good and evil on either side of her. So, not knowing what role she must play, she plunges into the comedy and turns the course of events upside down.
There is a fatalistic streak in Nastasya; she seems to sense from the first that her destiny is with Rogozhin, just as Myshkin senses, in an almost clairvoyant way, that not only will Nastasya's rendezvous be with Rogozhin but that it will result in her death. Death, in fact, hovers ominously throughout the novel. An attempt is made on Myshkin's life, various murders are discussed, plus the treatment and the attitudes of murderers; and Nastasya's birthday party comes to a climax in the death of one way of life — but not in the birth of another. Nastasya destroys her long-time relationship with Totsky to flee to nowhere. She merely escapes with Rogozhin, a pale-faced admirer who quakes in her presence but who, we learn, is capable of beating her black and blue.
Vacillating between Rogozhin and Myshkin in Moscow, Nastasya returns to Petersburg and tries to effect a marriage between Aglaia and Myshkin — two good souls. But Aglaia reveals herself to be venomous and even though Nastasya bests Aglaia by claiming Myshkin as a prize, she cannot let herself marry the prince; therefore, her final — and fatal — abandonment to Rogozhin.