Cognition
The Rule of Three: Why We're Fascinated by Trios
Why the human mind loves the number three.
Updated June 12, 2025 Reviewed by Kaja Perina
Key points
- Three is a recurring pattern in storytelling, language, and politics, among others.
- When things come in threes, they are experienced as deeply satisfying.
- This is because three is the smallest number required to create a pattern and rhythm.
Genies grant three wishes, the newborn Jesus was visited by three magi, and Goldilocks had to contend with three bears. Not one, nor two, nor four, but exactly three.
For all D’Artagnan’s heroism, Alexandre Dumas did not entitle his novel, The Four Musketeers. If asked, “How many ghosts visited Ebenezer Scrooge?” most people will answer, “Three”—completely forgetting about the fourth ghost, that of Scrooge’s partner, Jacob Marley.
Trilogies and trinities are a lot more common, and popular, than tetralogies and quaternities (if that’s even the word for them).
Rhetoric and Politics
In rhetoric, three parallel words, clauses, or lines make up a tricolon, which is a particularly effective type of isocolon (or parallel construction).
- I came, I saw, I conquered. —Julius Caesar, upon crossing the Rubicon
- Government of the people, by the people, for the people. —Abraham Lincoln in the Gettysburg Address
- Life, Liberty, and the Pursuit of Happiness. —The United States Declaration of Independence
Similar to tricolon is hendriatris, which involves the juxtaposition of three words to express a single idea or total concept, for example, Liberté, Egalité, Fraternité (the national motto of France) and “wine, women, and song” (or, nowadays, “sex, drugs, and rock’n’roll”).
Winston Churchill’s first speech to the House of Commons as prime minister is remembered as Blood, Sweat, and Tears, even though he said, “I have nothing to offer but blood, toil, tears, and sweat.” As prime minister of the United Kingdom, Tony Blair did not make his top priority “education” or even “education, education”, but “education, education, education”. When asked a question, Joe Biden often responded by making just two points (“Number 1… Number 2…”), leading everyone to expect a non-forthcoming third.
Three is a pattern
Why is three so much more engaging, satisfying, and memorable than one or two or four? "Here are my three reasons.” “I’ll give you three examples.” “These are the three lessons I learnt.”
One is a fluke. Two is a coincidence. Four is one too many—to the extent that if you must have four, it may be better to present them as two linked pairs, and then maybe add a third pair.
Three, however, is the smallest number required to create a pattern and rhythm.
Triple goddesses or deities in groups of three are common in world myth: the Holy Trinity, the Tridevi, Hecate, Artemis, the Fates, the Furies, the Graces, the Graeae, the Morrígan, the Norns… and, I believe, originally stood for fate and the passage of time—the past, the present, and the future.
In Greek myth, when Demeter discovered that her daughter Persephone had been kidnapped by her brother Hades, she abandoned her divine duties and wandered from city to city, bringing by her absence a blight onto the land. Arriving in Eleusis in Attica, she took the form of a crone by the name of Doso and fell upon the good King Celeus for sanctuary.
Persephone, Demeter, and Doso may be regarded as the three aspects of a triple goddess—the Maiden, the Mother, and the Crone—that stand for the phases of the moon and the stages of life.
No wonder, then, that the number three is so deeply ingrained in the human psyche.
References
Neel Burton is the author of the newly published How to Think Like Plato and Speak Like Cicero.
