LitCharts assigns a color and icon to each theme in Moby-Dick, which you can use to track the themes throughout the work.
Limits of Knowledge
Fate and Free Will
Nature and Man
Race, Fellowship, and Enslavement
Madness
Religion
Summary
Analysis
The Pequod comes across the Bachelor, a Nantucket whaling ship that is filled, completely brimming, with sperm oil, for it has had a successful whale hunt. The mood on the Bachelor is uniformly jolly, and when Ahab stops the captain during a brief gam and asks whether he has seen Moby Dick, the unnamed captain of the Bachelor replies that he “doesn’t believe that the whale exists.” Ahab grumbles and takes the Pequod away, against the wind and deeper into the Pacific, while the Bachelor readies itself for a pleasant return voyage to Nantucket, and a large payout for its sperm oil.
Ahab sees Moby Dick as a devil to be pursued above all other things. The Captain Bower in Chapter 100 saw Moby Dick as just another whale. This captain takes a different view: that Moby Dick is a myth, a kind of construct of all the scary experiences sailors have had with whales. And while within the context of Moby Dick this view is false—Moby Dick is a real whale that the Pequod finds and confronts—there is a sense is a myth: although Moby Dick exists, the stories that surround Moby Dick are largely concocted by sailors, as tales to tell. For Ahab, the story of Moby Dick—that he must exact revenge against a force or devil that wronged him—is more powerful than the physical reality of the whale itself.