He embodies Dostoevsky's theme that punishment imposed on a criminal does little good if the man himself rejects his own guilt.
In addition, Dostoevsky further elaborates Raskolnikov's character by introducing his similarities to Porfiry. Porfiry is the only character that is Raskolnikov's intellectual equal and therefore understands the complex motives for his crime. He uses an ironic, mocking tone when he speaks to Raskolnikov, which reminds us of the arrogance Raskolnikov himself shows other people. The investigator's emphasis on psychological analysis as a way of detecting criminals is almost as revolutionary as Raskolnikov's belief in crimes of principle. Porfiry studies he suspect (Raskolnikov) shrewdly, frequently asking questions in order to stimulate response. When talk of the murders comes up, Porfiry observes the way Raskolnikov is instantly thrown into a fit of mental and physical torment. Porfiry devise theories about his suspect and continues to play a "cat and mouse" game with Raskolnikov until he confesses. Without him, Raskolnikov may have never been suspected and, more importantly, would never have been rehabilitated. Porfiry's success illustrates the theme of conformity to the law and traditional Christian ethics as the foundations of a productive life.
Dostoevsky introduces one of the most dynamic characters, Sonia, as combination of the Madonna and the whore, split between purity and evil deeds. Forced into prostitution by poverty, Sonia struggles to fend for her family. Although many characters in the novel look down upon Sonia, Dostevsky preserves her child-like innocence:.
She could not have been called pretty, but her blue eyes were so clear, and when they lighted up there was such a kindliness and simplicity in her expression that one could not help being attracted. Her face, and her whole figure indeed, had another peculiar characteristic. In spite of her eighteen years, she looked almost a little girl- almost a child" (Page 243).
