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
Ishmael lays out some fossil evidence for the existence of whales in far-flung locales, including the “Lombard region” of Germany and the state of Alabama in the US, where a whale was uncovered in the 19th century and believed to be a monster from the Old Testament. Ishmael states that this conception of the whale’s monstrosity is not far off; he adds that, in other jobs he has worked as a “digger” and a “miner,” and has come into contact with a good deal of fossilized bones of all types of animals. This, he believes, gives him some credential as a “geologist,” and therefore allows him to speak on this subject of the whale’s fossil ancestors.
Having investigated the skeleton of a whale and finding that doing so, once again, leaves him not truly understanding the true sublimity of the whale, Ishmael now tries to place the whale skeleton into a geologic context. But again there is mystery rather than answers, as whales have been found in places where there is no ocean, and when found was believed not even to be a whale but rather a figure of mystery: a biblical monster.