Themes are the fundamental and often universal ideas explored in a literary work.
The Limits of Knowledge
As Ishmael tries, in the opening pages of Moby-Dick, to offer a simple collection of literary excerpts mentioning whales, he discovers that, throughout history, the whale has taken on an incredible multiplicity of meanings. Over the course of the novel, he makes use of nearly every discipline known to man in his attempts to understand the essential nature of the whale. Each of these systems of knowledge, however, including art, taxonomy, and phrenology, fails to give an adequate account. The multiplicity of approaches that Ishmael takes, coupled with his compulsive need to assert his authority as a narrator and the frequent references to the limits of observation (men cannot see the depths of the ocean, for example), suggest that human knowledge is always limited and insufficient. When it comes to Moby Dick himself, this limitation takes on allegorical significance. The ways of Moby Dick, like those of the Christian God, are unknowable to man, and thus trying to interpret them, as Ahab does, is inevitably futile and often fatal.
The Deceptiveness of Fate
In addition to highlighting many portentous or foreshadowing events, Ishmael’s narrative contains many references to fate, creating the impression that the Pequod’s doom is inevitable. Many of the sailors believe in prophecies, and some even claim the ability to foretell the future. A number of things suggest, however, that characters are actually deluding themselves when they think that they see the work of fate and that fate either doesn’t exist or is one of the many forces about which human beings can have no distinct knowledge. Ahab, for example, clearly exploits the sailors’ belief in fate to manipulate them into thinking that the quest for Moby Dick is their common destiny. Moreover, the prophesies of Fedallah and others seem to be undercut in Chapter 99, when various individuals