Pythagorean Numerology: Method and Origins

What is Pythagorean numerology?

Pythagorean numerology is the system most people mean when they say numerology. It reduces a date of birth to a life path number and a name to an expression number by giving each letter of the alphabet a value from 1 to 9 in alphabetical order: A is 1, I is 9, J starts again at 1. The method is simple, consistent and easy to check, which is why it dominates books, apps and this site. Its name honours Pythagoras of Samos, the philosopher of the 6th century BCE who taught that number is the principle of all things; but the letter table and the five personal numbers were devised in the United States between 1908 and 1965, and Pythagoras never computed a name. This page separates the two clearly: what the Pythagoreans really thought and calculated, which is fascinating in its own right, and the modern method, with worked examples you can reproduce in a minute.

• Letters are valued 1 to 9 in alphabetical order; the cycle restarts at J and at S.
• The life path comes from the full birth date, the expression number from the full name.
• Master numbers 11, 22 and 33 are kept unreduced in the modern method, not in antiquity.
• Pythagoras taught number as the structure of the world; the name-reading system dates from 1908.

Pythagoras and his school: what we actually know

Pythagoras was born on the island of Samos around 570 BCE and settled around 530 in Croton, in southern Italy, where he founded a community that was at once a school, a religious brotherhood and a political faction. He wrote nothing. What we know comes from later authors: Philolaus of Croton, whose fragments from the late 5th century are the oldest Pythagorean texts; Aristotle, who summarised the doctrine in his Metaphysics with the phrase that the Pythagoreans held things to be numbers; and, much later, Nicomachus of Gerasa around 100 CE, Porphyry and Iamblichus in the 3rd and 4th centuries, who wrote the biographies and the arithmetical treatises that transmitted the tradition. The community observed a rule of silence and shared property, abstained from certain foods, and taught the transmigration of souls. Its two famous discoveries, the theorem on right triangles and the numerical ratios of musical intervals, were probably collective work rather than the master’s alone.

The first ten numbers as principles

The Pythagoreans did not interpret numbers as personality traits; they interpreted them as stages in the unfolding of the world. The monad, 1, is the source and is not yet a number in the ordinary sense; the dyad, 2, is the first division and the beginning of plurality; the triad, 3, the first number with beginning, middle and end, hence the first whole; the tetrad, 4, completes the tetractys; and the decad, 10, the sum of the first four, is perfection. The treatise known as the Theology of Arithmetic, compiled in the circle of Iamblichus from Nicomachus and older sources, records the epithets given to each number. The table gives those that are best attested. Modern numerology kept the sequence and translated the epithets into psychology: the pioneer of 1, the diplomat of 2, the communicator of 3.

The arithmetic the Pythagoreans really practised

The Pythagoreans worked with pebbles, arranging units into figures, and their arithmetic was a study of such figures. Triangular numbers, 1, 3, 6, 10, 15, are the sums of consecutive integers; square numbers, 1, 4, 9, 16, 25, are the sums of consecutive odd numbers, which is why adding an odd number to a square gives the next square. A perfect number equals the sum of its divisors: 6 is 1 + 2 + 3, 28 is 1 + 2 + 4 + 7 + 14; Nicomachus lists 6, 28, 496 and 8128, the four known in antiquity. Two amicable numbers are each the sum of the other’s divisors: 220 and 284, a pair that Iamblichus attributes to Pythagoras himself and that was still used as a token of friendship in the Middle Ages. None of this is numerology in the modern sense, but it is the ground on which the idea of numbers with qualities was built, and every figure in the table can be checked by hand.

Harmony: the ratios of the monochord

The discovery that the school prized most was musical. Stretch a string, stop it at half its length and you hear the octave; at two thirds, the fifth; at three quarters, the fourth. The consonances of music are the ratios 2:1, 3:2 and 4:3, formed from the numbers 1 to 4 of the tetractys, and the whole tone is the difference between fifth and fourth, 9:8. From this the Pythagoreans reasoned that the planets, moving at different speeds, must also sound in ratio, a harmony of the spheres that we do not hear because we have heard it since birth. Kepler was still looking for those ratios in the orbits two thousand years later.

The modern letter table and the five personal numbers

The method taught today assigns the 26 letters of the Latin alphabet to the digits 1 to 9 in order, so that A, J and S are 1, B, K and T are 2, and so on to I, R and Z. It was first published in this form by the American music teacher L. Dow Balliett in 1908, in The Philosophy of Numbers, and codified by her follower Juno Jordan in 1965. From the birth date and the name it derives five numbers: the life path, the expression, the soul urge from the vowels, the personality from the consonants, and the birthday. Each total is reduced to a single digit, except 11, 22 and 33.

Master numbers: 11, 22 and 33

The modern method does not reduce 11, 22 and 33 when they appear as a total: it reads them as master numbers, carrying both their own meaning and that of their reduction, 2, 4 and 6. The idea has no ancient source; 11 and 22 appear in the American books of the 1920s and 1930s, and 33 was added later. Michael is the clearest example in this table: M 4 + I 9 + C 3 + H 8 + A 1 + E 5 + L 3 = 33, read as the master teacher, which also means that a Michael who reduces fully is a 6. The same name gives 22 in the Chaldean table, another master number, but one about building rather than teaching. Master numbers are best read as an intensified 2, 4 or 6, with a higher demand and a higher cost, rather than as a promise.

From Croton to the modern method

The road from the Pythagorean school to the numerology app runs through three transmissions. Plato absorbed the doctrine of number into his cosmology, and Neoplatonists such as Nicomachus and Iamblichus wrote the arithmological treatises that the Middle Ages read. The Renaissance, with Marsilio Ficino and Cornelius Agrippa, mixed that inheritance with the Kabbalah and with letter-number correspondences from Hebrew and Greek, where every letter had always been a numeral. Finally, around 1900, American authors transferred the idea to the Latin alphabet, which had never carried numerical values, and produced the table used today: L. Dow Balliett in 1908, Sepharial in London in 1913, Florence Campbell in 1931, Juno Jordan in 1965. Calling the result Pythagorean is a homage, not a lineage.

• Balliett 1908, Sepharial 1913, Campbell 1931, Jordan 1965: the modern method in four dates.
• Greek and Hebrew letters were numerals; Latin letters never were, until 1908.
• The Pythagorean part worth keeping is the arithmetic and the ratios, not the name table.