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 explores whale fishing and its relation to the law. In particular, Ishmael describes the doctrine of the “fast fish” versus the “loose fish.” Any whale that has been harpooned and tied to a ship is the property of that ship’s crew, and cannot be taken from that crew—to do so would be theft. But on the high seas, if a ship loses its line on a whale, and lets it drift away—even if that ship caught the fish—the fish is a “loose” one, and can be claimed by anyone. Ishmael says that this policy might be a difficult one for some to see as fair, but he notes that many things in life follow this philosophy. For example, if a man leaves his wife, that wife is free to marry another man—and the colonies snapped up by many nations were “loose” until claimed by colonial powers, like England and France. Ishmael then states that the reader himself is both a fast and a loose fish—bound to some conventions in life, and free of others.
Ishmael turns to another lens of human intellect to define and discuss whales: the law. Ishmael believes that the legal distinction he describes to be of chief importance in life as well as in the law. Man’s strivings, to Ishmael consist always of attempting to grasp things that elude man. These “things” might include money, prestige, or power—they might also include the white whale itself, which eludes constantly Ahab’s grasp. Man’s attempt to “make fast” that which is “loose” is a feature of the human condition, as is man’s failure ever to finally, totally “secure” that which it desires. Here, then, Ishmael views the laws of fast and loose fish to be a reflection of this philosophical distinction between security and chaos. In addition, Ishmael takes these laws of whaling—which might seem ridiculous or inconsequential to non-whalers—and shows how they are identical to very real circumstances. And yet, were those colonies truly "loose"? Only to the colonial powers conquering them. Likewise, is a whale truly "loose"? Or does it belong to itself?