Our stories like the number three: There are three little pigs and three bears, as well as Harry, Ron and Hermione. Our movies like threes, as Star Wars now embarks on the last of its three trilogies. Our advertisements like the number three as well: the iPad 2 is "thinner, lighter, faster." Our warnings like the number three: "stop, look, and listen." Rules of real estate like the number three: "location, location, location." Political mottos like the number three: "liberté, égalité, fraternité" which also inspired "Life, liberty, and the pursuit of happiness." And religion likes the number three: "faith, hope and charity" brought to you by "The Father, the Son, and the Holy Ghost." Three is a magic number according to no lesser authority than Schoolhouse Rock

And there is more to all of these examples than just chance or random convention. As a rhetorical device, grouping meaning into sets of three is not just pervasive, it is also persuasive. There is something satisfying and cognitively "complete" in a set of three. Three adjectives, a three-part theme, or three main points provide a construction that feels instantly familiar and ends up being easier to remember. The rule of three has frequently been used by the great orators who have contributed some of the most durable lines of our times - speakers like Martin Luther King and John F. Kennedy (coincidentally, both known for their three-part names). When litigators are looking for a way to paint a bit of style and rhetorical effectiveness into their oral arguments, openings, or closings, the rule of three ought to be one of the first items in your tool box. Focusing on -- you guessed it -- three reasons, this post will explain why. 

The Rule of Three is Simple

It is common, especially in these days of infrequent trials, for busy litigators to think that they lack the skills or the disposition to be a William Jennings Bryant or an F. Lee Bailey. And it is true that genuine persuasive effectiveness is unlikely to come without a lot of preparation and practice, and too much conscious "style" in the courtroom can end up looking insincere. But the rule of three is one of the easier rhetorical tools to understand and to use, and it can be worked into your persuasion without calling too much attention to itself. 

Need to apply a critical adjective? Think of two more for emphasis and "dishonest," becomes "willful, reckless, and dishonest." What does the jury need to understand about this complex contract? How about the "three main parts" of the agreement. Want the jury to understand a detailed narrative? How about grouping the story into three parts: A beginning, a middle, and an end. Need to flesh out a point? How about providing three examples. 

The Rule of Three is Logical

The skeptic might be prone to thinking that there is nothing magic about three and good communicators simply copy each other. That latter part is true, but as far as the rule of three is concerned, there are some good reason to believe it has a natural basis. For instance, in mathematics, the rule of three means that the third number confirms a pattern. You hear 2, then 4, but you don’t know if you’re just counting by twos until you hear that the next number is 8 and you know that you're doubling. In music, it takes three notes to make a chord, and it is also the third note in a sequence that reveals what scale you're playing and whether it's in a major or minor key. Beyond human conventions, there seems to be something that nature prefers about the pattern-setting ability of the number three.  

The Rule of Three is Effective

Lists of three are sticky, which is to say, memorable. In 1956, George Miller of Harvard University published his classic article entitled, "The Magical Number Seven, Plus or Minus Two” focusing on the hard limits on human working memory. Miller cites research showing that we have a difficult time remembering more than five to nine items in our short-term memory. And that's a maximum. Back off a bit from that threshold, and you've got the number three as a good entry point! A telephone number, for instance, could be expressed as a continuous string of ten digits, but it isn't: The first two sets of numbers are always presented in groups of three.

Of course, the number is not always three (the last part of the phone number is four). In this blog, I try to keep the number of implications or recommendations small and manageable. So I'll sometimes have four, sometimes two. But most often, I find myself gravitating to that magic number three. I and other writers and speakers prefer three for a good reason: It is a large enough list to set a pattern, but a small enough list to be easy, clear...and memorable! 

In Latin, there is an expression that translates to "everything that comes in threes is perfect," or alternately as, "every set of three is complete." And, leave it to the Romans, they managed to express it in a three-word phrase: Omne trium perfectum.