Dostoevsky carefully details in this book the special sort of characterization needed for the enigmatic Smerdyakov, the son who will murder Karamazov. We learn, for example, that he "seemed to despise everybody," including his real father and also his foster father. It is clear that he could conceivably murder either one, and in cold blood. Furthermore, we learn that in childhood "he was very fond of hanging cats," certainly a sadistic and perverse pastime. As a complement to his psychological ills, he is physically sick; epilepsy, a disease he inherited from his idiot mother, overtakes him on occasion. Of late, nervous fits have attacked him increasingly, and it is one of these attacks that he later shams as his alibi when his innocence is questioned.
In his argument with Grigory, put forward to impress the intellectual Ivan, Smerdyakov uses the most basic semantic logic to prove his point. But the argument shows that he is interested in questions similar to those that disturb Ivan. In this way, Dostoevsky sets up conflicting emotions within Ivan. Because of their like interests, he is drawn to his half-brother, but at the same time, with a Dostoevskian duality of emotion, he is repulsed and sees him as a "mean soul."
The vulgarity of old Karamazov is once more emphasized in this section. This time, in the presence of Alyosha, he crudely ridicules his son's mother. This is a particularly painful scene because we have been told that Alyosha remembers his mother with deep love and respect.
