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
Ahab has a short conversation with the carpenter as he seals the coffin. Pip, following behind asks both the carpenter and Ahab, whether it isn’t strange to help a man to live, by making him an ivory leg, and then to make a life buoy out of something that normally holds dead bodies. The carpenter continues with his work, though he believes that Pip and Ahab are mad. Ahab, in a monologue at the end of the chapter, asks himself whether a casket isn’t always a “life preserver” for the immortal soul, but immediately stops in this line of thinking, telling himself that he must return to his hunt for the white whale. He calls to Pip, who has now taken to following Ahab around the vessel.
Here, Ahab makes explicit the idea that a coffin might be viewed as a life-preserver anyway—a means of keeping man safe as he continues in his journey into the next world. Once again, Ahab and Melville have decided to make explicit the symbolism of the novel. This, as a consequence, makes the novel feel more real, since the whale, the life-buoy, and other objects are perceived as symbols by the characters themselves. Thus the characters seem to have the same understanding of their surroundings that the reader does—making the characters seem more like the reader himself or herself. At the same time, the novel has again and again explored interpretations only to then undermine them. So Ahab's real-ness in his identification of symbols also serves to question the interpretations of the readers of those same symbols. The carpenter, meanwhile, thinks everyone wasting time with all this interpreting is crazy.