How are Sutpen and Bon alike?

Chapter Four underlines the similarities between father and son, Sutpen and Bon. They both have a child from a previous marriage. They are both described as calculating, worldly and inhumane. Bon's mother is a colored woman, which places him in the middle of the moral spectrum of the novel (where color superficially represents good and bad / wild and civilized etc). He is neither unquestionably immoral, nor irreproachably good, as his name might suggest (bon is from the French word meaning "good").