The rule of three is a storytelling convention popular in fables, folk tales and children’s stories. It is when something happens two times with the same result then a third with a different one. Examples include:
- The Three Little Pigs
- The Three Billy Goats Gruff
- Goldilocks and the Three Bears
You see it a lot in western fairy tales. Snow White’s stepmother tries to kill her three times. Jack climbs the beanstalk three times. In Aesop, the boy cries wolf three times. In modern screenwriting, Aristotle’s Three Act Structure still predominates.
In other fields, the rule of three goes much further. Popular wisdom claims ‘third time’s the charm’. Art theory employs the parallel ‘rule of thirds’ and rules of three apply to statistics, survival and aviation. Of the world’s 194 recognised countries, 174 have three colours in their flags.
Rhetoric also uses the rule of three. Adages with three beats are easier to remember and recall. In his 1940 address, Churchill actually promised ‘blood, toil, tears and sweat, but people remembered it as ‘blood, sweat and tears’.
- Veni, vedi, vici (I came, I saw, I conquered)
- Liberte, egalite, fraternite
- Life, liberty and the pursuit of Happiness
- Friends, Romans, countrymen
- Sex, drugs and rock n’ roll
- Stop, look and listen
- On your marks, get set, go!
- Mirror, indicate, manoeuvre
- First, second and third place
- Rock, paper scissors
- Mind, body and soul
- Past, present, future
- Beginning, middle and end
We see three dimensions. There are three primary tenses and three primary colours. Modern governments have three branches and there are three emergency services.
Pythagoras claimed three was the noblest number as it was the only one who equalled the sum of its predecessors. 1+2=3. The Socratic method relies on asking three questions in a row. Chinese numerology considers the number three lucky.
You also see the motif in religion and mythology. Hinduism has the Trimurti (Brahman the Creator, Vishnu the Preserver and Shiva the Destroyer), Christianity has its Holy Trinity, Greek mythology has the three sons of Chronos (Zeus, Poseidon, Hades), Buddhism has the Threefold Path of ethics, wisdom and meditation. The Zoroastrian mantra is ‘Good thoughts, good words, good deeds.’ Divisions of existence into three planes (generally, but not always Heaven, Earth and Underworld) is also common. The trope is most prevalent in Indo-European traditions, perhaps owing to their societies’ ancient threefold division into warriors, priests and farmers.
The rule of three makes telling it easier to tell a story from memory – especially true with jokes – where the punchline is delivered on the third try. Three allows sufficient variety and complexity without confusion. The first two beats start a rhythm, the third adds a surprise. Three is the smallest number to make a pattern.
Sources: Jonathon Crossfield, TV Tropes, Wikipedia