"[Ahab] morally enfeebled also, by the incompetence of mere unaided virtue or right-mindedness in Starbuck, the invulnerable jollity of indifference and recklessness in Stubb, and the pervading mediocrity in Flask. Such a crew, so officered, seemed specially picked and packed by some infernal fatality to help him to his monomaniac revenge.”
By this chapter, we know that Ahab wants revenge on Moby-Dick for the taking of his leg. We read about the horrible return voyage where Ahab suffered in madness and pain. We realize that Ahab is not interested in money, but only in seeking revenge. We know it all. But even knowing the end of the tale, Melville manages to keep us interested.
Ahab could not have acted alone. He was aided by three kinds of people – the righteous, the uncaring, and the ones in the middle. When a mad man takes the helm, all three of these kinds of people inevitably surround him.