The introduction of Marmeladov at this point is central to Raskolnikov's theories. He has just left a woman (Alyona Ivanovna) who is filthy, greasy, and lives the life of a "louse"; he is repulsed by her and plans to murder her. Yet, here he meets Marmeladov who is also filthy, greasy, with dirty hands and is a horrible, abject creature who has allowed his own daughter to enter prostitution so as to help support his drinking habits; yet rather than seeing him as a "louse," the opposite feelings are evoked in Raskolnikov — he responds with sympathy and compassion to this outwardly useless creature.
This meeting with Marmeladov this early in the novel establishes Raskolnikov's dual personality. Throughout the novel, we should remember that Raskolnikov functions either as a warm, compassionate, and humane individual willing to help the downtrodden, or else as a cold, detached, intellectual being who must stand apart from others in order to justify his theories of the Ubermensch. At the beginning of Chapter 2, he has avoided all society of late but after his meeting with the pawnbroker (Alyona Ivanovna), he has a desire to embrace humanity. And his humanitarian impulses cause him to leave all (or most) of his scarce money to Katerina, but almost immediately, he changes his mind and "would have gone back."
The meeting with Marmeladov is also important in establishing future relationships. First, Marmeladov's narration introduces Sonya and the entire Marmeladov family. It prepares Raskolnikov to look upon Sonya as a victim and see in Marmeladov's own sufferings the sufferings of Sonya. He is attracted to her because of her suffering. Then, at the end of the novel just before his confession, he acknowledges his attraction to her because she represents "the suffering of all humanity."
