Obsession is probably the single most common theme students choose to write about in Moby-Dick, largely because Ahab's monomania is so explicit and so central to the plot. That popularity is a double-edged sword for grading: the theme is easy to find evidence for, but it is also easy for students to write a competent, familiar essay without saying anything particularly new.

The word "monomania" itself, which Melville uses directly to describe Ahab, is worth having students engage with as a specific term rather than a synonym for generic obsession. Nineteenth-century psychology used the term to describe a single fixed, irrational idea within an otherwise functioning mind, and understanding that context sharpens student analysis considerably.

Strong essays on this theme tend to move beyond simply cataloguing evidence of Ahab's obsession and instead examine how that obsession functions structurally in the novel, shaping the crew's fate, distorting Ahab's leadership, or serving as a commentary on human ambition more broadly.

Weaker essays often stop at description: they identify moments where Ahab is obsessed and explain that this obsession is bad or destructive, without pushing further into why Melville constructs the novel this way or what it asks readers to consider about their own convictions.

Prompt Design That Pushes Past the Obvious

A prompt that simply asks students to "discuss Ahab's obsession" invites the safest possible essay. Sharper prompts ask students to take a position on what that obsession costs, or to compare it to another character's more moderate convictions.

• Argue whether Ahab's monomania is presented as tragic, heroic, or both
• Compare Ahab's obsession to Starbuck's steadier sense of duty
• Examine how the crew's complicity complicates Ahab's individual responsibility
• Discuss whether the novel offers any alternative to obsession as a driving force
• Analyze a specific scene where Ahab's obsession briefly falters

Grading Criteria That Reward Depth

A rubric for this theme should explicitly separate identification of the theme from analysis of its function, since so many essays will succeed at the former without attempting the latter.

Giving partial credit for thorough evidence gathering while reserving top marks for interpretive depth helps students understand precisely where their essay currently sits and what the next step for improvement looks like.

Handling a Class Full of Similar Arguments

Because so many students choose this theme, teachers often end up reading a dozen or more essays that make nearly the same basic point. Grading these fairly requires staying alert to small but meaningful differences in evidence selection and argument sophistication, rather than letting essay fatigue flatten your assessment of later papers in the stack.

Taking short breaks between essays on the same theme, or intentionally alternating topics while grading, can help preserve that attentiveness across a large stack.

Using Feedback Tools to Catch Repetitive Patterns

AI-assisted feedback tools can help here by flagging when an essay relies heavily on the same handful of commonly cited passages without offering original analysis, giving teachers a useful signal for which essays need closer individual attention.

That signal helps teachers spend more time on the essays doing something genuinely distinct with a familiar theme, which is usually where the most useful classroom conversations about the novel begin.