The past and the present and the future.
Faith and hope and charity.
The heart and the brain and the body
give you three as a magic number.
- Bob Dorough, Schoolhouse Rock (1973)
In Harry Potter and the Half-Blood Prince, a young Tom Riddle asks Horace Slughorn, “Can you only split your soul once? Wouldn’t it be better, make you stronger, to have your soul in more pieces? I mean, for instance, isn’t seven the most powerfully magical number, wouldn’t seven-?” (Rowling, 466). Rowling herself answers this last question repeatedly throughout the series – a resounding “No.” Seven is not the most powerfully magical number. In the Potterverse, as in many other places in literature and mythology, the most powerfully magical number is three.
For example, Greek mythology is full of references to threes. The Moirae (or The Fates) were three sisters that held the thread of life of every mortal; Clotho spun the thread, Lachesis measured it, and Atropos cut it. The sisters represented the three phases of life: birth, aging and death. Similarly, the Musai (or The Muses) were made up of nine (i.e. three times three) goddesses: Euterpe (music), Polyhymnia (the sacred), Calliope (poetry), Terpsichore (dancing), Clio (history), Erato (lyric), Thalia (comedy), Melpomene (tragedy) and Urania (astronomy) – each lending their inspiration to a form of art significant to the Greeks (interestingly, originally, there were only three Muses: Aoide - song, Melete – practice, and Mneme - memory). Of course, moving into the Christian era, the Holy Trinity emerged as primary: the Father, the Son and the Holy Spirit, representing, in turn, Power, Love and Knowledge.
In many major and minor ways, Rowling continually returns to the number three as symbolic of what might be called “perfect balance.” And, at the very core, a trinity of triads are central to the story itself: the three Unforgivable Curses (Crucio, Imperio and Avada Kedavra), the three Deathly Hallows (the Resurrection Stone, the Elder Wand and the Invisibility Cloak), and the most important of all, the Trio (Harry, Hermione and Ron). In each, we find similar elements: power, love and knowledge. The power the Elder Wand, the ability to remove power with Crucio, the physical power of Harry Potter. The ability to return loved ones to life with the Resurrection Stone, to end the life of other’s loved ones with Avada Kedavra, the emotionality and heart of Ron Weasley. The knowledge one can obtain (and the wisdom of passive resistance) through use of the Invisibility Cloak, the control over the knowledge of others with Imperio, the brainpower and logic of Hermione Granger. In fact, I have argued in my own work quite strenuously that Harry Potter isn't even the main protagonist of the series; the protagonist is a classic trinity structure: hero, anti-hero and heroine, with Harry, Ron and Hermione filling those respective roles. None of the three can achieve without the other two; they are utterly symbiotic.
In each triad within the trinity of power in the Potterverse, each element is just as powerful as the other two, but specialized and unique – imbued with a particular locus of power rather exclusive to it. What those loci are and where they lie is, of course, open to interpretation.