At one point the Underground Man says that twice two makes four, this is a scientific fact, but man does not always function merely by scientific fact. For Dostoevsky, the rational part of a man's being is only one part of his makeup. That is, man is composed both of the rational (two times two does make four) and the irrational — "it would be nice to think sometimes that twice two makes five." This would be, in Dostoevsky's words, "a very charming idea also." The point is that if man functions solely as a rational being, then man's actions are always predictable. Thus, Dostoevsky's point is that man's actions are NOT predictable. Raskolnikov will rationally stop a young dandy from having his way with a young girl and then suddenly decide it is none of his business, or he will tell his sister that he forbids her marriage and then contradict himself by saying "Marry whom you please." Likewise, there are men who are only happy when they suffer; thus, the man who falsely confesses to the murder of the old pawnbroker wants to suffer, particularly to suffer at the hands of authority.
One of the great ideas throughout all of Dostoevsky's fiction is that through suffering man can expiate all his sins and become more closely attuned with the basic elements of humanity. Thus in Crime and Punishment, we have Dostoevsky bowing down to Sonya because she represents the sufferings of all humanity. Both Sonya and his sister Dunya feel that when Raskolnikov takes up his suffering, he will be purified. Also, a person of great conscience will suffer from his transgressions, and as soon as the crime is committed, Raskolnikov suffers so greatly that he does become physically ill and is in a semi-coma for days.
Raskolnikov, both in his published article about crime and in his own actions, was involved in determining the mental states that affect the criminal. The concepts of psychology and even some of its later terminology were used by Raskolnikov and Porfiry. Examples abound as to Dostoevsky's use of modern psychological concepts. Porfiry's entire investigative technique involves his use of psychology to trap his victim, and Raskolnikov recognizes this and refers to it as a cat and mouse game.
In terms of world literature, Dostoevsky stands out as the greatest master of the realistic psychological novel and has yet to be equaled by any modern masters.
