Understanding Arguments: The Rule Of Three

You may have encountered it in the Declaration of Independence (“Life, Liberty, and the pursuit of Happiness”), in fairy tales or novels (“The Three Little Pigs,” “Goldilocks and the Three Bears,” The Three Musketeers), or even in Aristotle’s Rhetoric (Logos, Ethos, Pathos).

Look closely, and you’ll find the Rule of Three is all around us.

The Rule of Three describes a common rhetorical strategy for advertisers, lawyers, or anyone who persuades people for a living: lists of three are often more memorable, satisfying, and funny than lists of one, two, four or more.

Why is this? Well, it’s much more difficult to say why this is, exactly, than to describe the appeal of triads.

In Writing Tools: 55 Essential Tools for Every Writer, Roy Peter Clark explains: “We use one for power. Use two for comparison, contrast. Use three for completeness, wholeness, roundness. Use four or more to list, inventory, compile, and expand.”

To illustrate his point regarding the other numbers, Clark offers a keen analysis of the opening of Jonathan Lethem’s novel Motherless Brooklyn:

Context is everything. Dress me up and see. I’m a carnival barker, an auctioneer, a downtown performance artist, a speaker in tongues, a senator drunk on filibuster. I’ve got Tourette’s.

Clark notes that these sentences follow a pattern of 1-2-5-1. “In the first sentence the author declares a single idea, stated as the absolute truth. In the next sentence, he gives the reader two imperative verbs [“Dress” and “see”]. In the next, he spins five metaphors. In the final sentence, the writer returns to a definitive declaration—so important he casts it in italics.”

The lines of one make strong declarations, while the line of five puts forward a list that seems as if it could go on forever. What we get there isn’t a sense of completion, but a feeling of infinity. What’s missing here is a line of three, which would provide a sense of wholeness and balance, inappropriate for an opening that wants to throw its reader into a chaotic array of identities.

Triads suggest wholeness, balance, and completion. They structure much of American culture, from the three branches of government (executive, legislative, and judicial) to the Three Stooges (Larry, Curly, and Moe).  

The Rule of Three has been ingrained in many of us since childhood. In fact, there’s a good chance you’ve learned to write through the Rule of Three.

Most high school and college students have learned some version of the five-paragraph essay, typically structured, of course, with three sections: an introduction, three body paragraphs, and a conclusion. These three parts satisfy the strictures of an old triadic chestnut about persuasive writing: “Tell them what you’re going to say. Say it. Then tell them what you said.”

This structure follows the pattern of a familiar triad: beginning, middle, and end.

But why three body paragraphs?

Body paragraphs are typically where students store their evidence, and they’re usually organized around three distinct examples or pieces of textual evidence. In order to defend one’s thesis, it makes sense to provide three examples, since three is the lowest number capable of establishing a pattern.

Think of the old adage: “one’s an incident, two’s a coincidence, and three’s a pattern.” Just one piece of evidence probably won’t do the trick. Two is a bit better, but typically not convincing. At three, you’ve established a pattern and a sense—often an illusion—of completion or wholeness.

Indeed, one of the most famous pieces of oratory employs the Rule of Three to account for all of humanity:

When we let freedom ring, when we let it ring from every village and every hamlet, from every state and every city, we will be able to speed up that day when all of God’s children, black men and white men, Jews and Gentiles, Protestants and Catholics, will be able to join hands and sing in the words of the old Negro spiritual, “Free at last! Free at last! Thank God Almighty, we are free at last!”

In the closing of his famous “I Have a Dream” speech, Martin Luther King, Jr. weaves together a series of triads to brilliant effect. The word “we” is used three times to link his three clauses. Then there’s the catalogue of pairs—“black men and white men, Jews and Gentiles, Protestants and Catholics”—meant to cover the total scope of “God’s children.” Of course, there are many races and creeds omitted here, but the rhetorical effect remains: MLK achieves a sense of totality. And finally, there’s the repetition of “Free at last!”— the third, final, and most dramatic use of the Rule of Three in this paragraph.

The Rule of Three is a valuable strategy to be able to identify, but also to be able to deploy.

For those working on college applications, it’s a useful tool for painting a complete portrait of yourself in your college essays. After all, these essays are rooted in the temporal triad of your life. That is, they’re meant for you to give colleges an account of your past, a feel for your present, and a vision of your future.