Ten is the num­ber of cre­ation's com­ple­tion, the cos­mic full­ness. Ten can be reduced to one, which is at once a return to the begin­ning and a step for­ward into full­ness. So, besides com­ple­tion and per­fec­tion, ten is always trans­form­a­tion, trans­ition and rebirth. As the out­come of the num­bers before it, ten embraces everything, con­tain­ing and unit­ing them. Ten is the first com­plete per­fec­tion, and as such the sign of law, order and domin­ion.

Accord­ing to Pythagoras, num­bers per­vade all the ele­ments of the uni­verse and find expres­sion in ten prin­ciples arranged in pairs: 1. finite – infin­ite, 2. odd – even, 3. unity – mul­ti­pli­city, 4. right – left, 5. male – female, 6. at rest – in motion, 7. straight – curved, 8. light – dark­ness, 9. good – evil, 10. square – rect­angle.

Since the Pythagorean sym­phoni­ai (con­son­ances) can be described pre­cisely by the ratios of the first four num­bers, their sum, ten (1 + 2 + 3 + 4), expresses a high­er qual­ity, the har­mony of nature. Pythagoras spoke of ten spheres: the Cos­mos, Sat­urn, Jupiter, Mars, the Sun, Venus, Mer­cury, the Moon, the Earth and the Counter-Earth – the last an ima­gined plan­et, or more pre­cisely a cos­mic cent­ral fire, around which the known plan­ets revolve.

By study­ing the rela­tions between num­bers, the Pythagoreans also uncovered the links between music­al har­mony, cos­mic order and moral norms, and math­em­at­ics was noth­ing less than a means of approach­ing the divine essence.

Ten, the most per­fect num­ber, is the sum of the first four num­bers: 1 + 2 + 3 + 4 = 10. In this lies the secret of the world, which is shown geo­met­ric­ally by the per­fect tri­angle, the sac­red tet­rac­tys. Ten con­tains as many even num­bers as odd ones, and so it also reflects ulti­mate har­mony.

In the time of Pythagoras people coun­ted with small pebbles, and the sac­red tet­rac­tys is a tri­angle of such pebbles, or points, in which the first row is formed by one point, the second by two, the third by three and the fourth by four, that is, ten in all. This sac­red tet­rac­tys was the sign of the fel­low­ship, and on admis­sion the can­did­ates swore their oath upon it.

Read from the top row down, the fig­ure traces the cre­ation and unfold­ing of the world. The single point stands for the cre­at­ive spir­it, the monad, the source of the uni­verse. In the second row the two points are dual­ity, the appear­ance of mat­ter. The three points of the third row are the union of spir­it and mat­ter, and the four points of the fourth row the cre­ated world of forms. Besides the small tet­rac­tys, which is the sum of the first four num­bers, there is also the great tet­rac­tys, set out as fol­lows:

great tet­rac­tys:

1 + 3 + 5 + 7 = 16

+ 2 + 4 + 6 + 8 = 20

The num­bers of the great tet­rac­tys add up to 36, which mul­ti­plied by two gives us the time-code (36 × 2 = 72), and if we mul­tiply this res­ult by the num­ber of man, the full cycle appears, the full circle (72 × 5 = 360°).

It is sup­posed that ten was a num­ber ready to hand, the num­ber of fin­gers on both hands. At Troy the siege dragged on for nine years without suc­cess, and in the tenth year the city fell. The cher­ubim of the Ark of the Cov­en­ant were ten cubits high, and in Chris­tian­ity, among the theo­lo­gic­al vir­tues, ten is the sym­bol of faith, a hun­dred of hope and a thou­sand of love.

In the Far East the uni­verse is divided into ten dir­ec­tions, the car­din­al and inter­me­di­ate points of the com­pass togeth­er with the zenith and nadir, above and below. God does not aban­don the uni­verse divided in this way, and Vish­nu des­cends in ten forms: as the Fish, the Tor­toise, the Boar, the Man-Lion, the Dwarf, the Axe-Wield­er, Bliss, the Dark One, the Enlightened One, and the Rider on the White Horse, still to come.