I. What is an Excursus?
An excursus is a moment where a text moves away from its main topic – it’s roughly similar to “digression.” However, excursus in a formal essay usually occurs in a footnote or appendix, whereas digression appears in the body of the text.
In any particular argument or story, the meaning of excursus depends on what one takes as the main subject. In many cases, of course, this is a subjective judgement.
II. Examples of Buzzword
Imagine a science fiction story about colonizing Mars. The main story is about how the colonizers survive and work together (or don’t) as they build their settlement. If the author spent a full chapter explaining the details of the Martian atmosphere, it might be considered an excursus. However, if those details are ultimately important for the story later on, it wouldn’t be.
Something similar can happen in a formal essay. Let’s say you were writing about the early history of Coca-Cola. Should you include an explanation of Coke’s formula and the original ingredients that went into it, or would that be an excursus? The answer, of course, is that it depends. If the focus of the paper is marketing and corporate growth, then the formula is probably less important, although it may still help explain, for example, the drink’s popularity (by pointing out the powerfully addictive properties of many of its ingredients). Whether or not this explanation is an excursus depends entirely on how readers feel about it.
III. The Problem with Excursus
As a writer, you’re asking your reader to trust you. You’re saying implicitly that what you’ve written is of some value to them. In a story, that value might be entertainment or inspiration, whereas in non-fiction it’s persuasion and information. You have an unwritten pact with the reader: they give you time and attention, and you promise not to waste it. An excursus is a violation of that pact.
However, if you want to explain a certain point further but aren’t sure it will be interesting to all your readers, you can place it in a footnote or appendix. This way, readers who want to know more will have the information available, but less patient readers will have permission to skip it.
IV. Examples of Excursus in Literature
Herman Melville was famous for including excursus in his novels. He left in entire chapters about rope, cetology (the study of whales) and other elaborate discussions of topics related to whaling. Readers who are only interested in the action aboard the Pequod may be irritated by these digressions, but for other readers they add texture and detail to the world of the novel.
John Rawls’s Political Liberalism is one of the 20th century’s most influential works of political philosophy, and its main argument is extremely tightly controlled – Rawls rarely leaves his main subject matter even for a paragraph. However, his footnotes frequently describe the relationship between his theories and other ways of thinking. For example, he has a lengthy footnote on the application of political liberalism to Islam. Since the book’s main argument is not about Islam in any way, this footnote is an excursus, but it may still be of interest to some readers.
V. Examples of Excursus in Popular Culture
The Lord of the Rings books and movies may or may not have instances of excursus, depending on how important you think the backstory is. For some people, it’s crucially important to understand the history of Middle Earth and how the events of the past affect the action in the story, in which case these explanations would be referred to as exposition. For other people, this information is not important, and therefore it’s an excursus.
Similarly, audiences had mixed reactions to the explanation of the Force in Star Wars: Episode I. For some, it was helpful to know what biological mechanisms produce the Force; for others, this information was utterly extraneous and disposable.
VI. Related Terms
This is just a synonym for “excursus.” However, digression has a strong negative connotation whereas excursus is more neutral. This is partially because authors can deliberately “offset” an excursus by putting it in an appendix or footnote, thus signaling to the reader that this particular portion of the text can be skipped. In fiction, excursus and digression mean exactly the same thing, and the connotation is always negative.
In narrative fiction, “exposition” is an explanation of the backstory, rules, or context of a story. For example, in Star Wars it’s necessary to explain how the Force works, what the political situation is within the Galactic Empire, and some of the relevant technology. If readers/viewers find this information necessary and useful, then it’s counted as valuable exposition – if they find it extraneous, then it’s excursus and should be removed.