The number 108
This is an interesting story, but it is putting the cart before the horse. The number 108 does not have such a single meaning as a metaphor for “the number of steps” required to “graduate” from this earth plane. Such a concept of graduation may exist in some branches of esoteric or tantric Buddhism but does not appear in Buddhism generally. There are many metaphors that may be derived from the number 108. In the Lotus Sutra is it said that the Pure Land is 108,000 li away. In the Platform Sutra of the Sixth Ancestor, the Zen master Huineng says this represents the 10 evils and 8 errors within us and if we put into practice the 10 good deeds and do away with the 8 errors then we have travelled the distance to the Pure Land in a twinkling of the eye. The Lankavatara Sutra mentions 108 statements of negation. D.T. Suzuki points out the Sanskrit word translated as “statements” is “pada” which can also be taking as “foot-steps”. This confusion of “pada” with steps is possibly the source of the concept that 108 is “steps” of some kind. But 108 is not a linear concept, such as steps to graduate from this world. 108 is a circular concept like the mala beads.
108 is 4 times three to the third power– which can be metaphorically conceived of representing the 4 truths times the objective cosmos consisting of the three realms (desire, form & formless) times the three poisons (greed, hatred and ignorance) times the three divisions of time (past, present, future). Other metaphorical meanings can be derived from the mathematical combinations of 108 as “4x3x3x3” or “12×9” or “4×27” etc. in addition to the many metaphors possible in the image of 108 as “10 and 8”. The point I would make is that all the metaphors relating to 108 are correct when applied appropriately (as expedient means), but no single such definition of 108 is correct as a literal one and only truth about 108.
The closest we can get to the origin of the mystical significance of 108 as a literal number is in the mystery of nature and the cosmos. Before Buddhism arose, the number 108 was already a sacred number within the Vedic worldview because of its astronomical significance. Since the measured distances vary according to orbital ellipsis, by rounding off to an apparent constant it was discovered that the moon is 108 of its diameters distant from the earth, the sun is 108 of its diameters distant from the earth, and the sun’s diameter is 108 times the earth’s diameter. This mystery of gravitational equilibrium and relative size made 108 a profoundly rich number for natural significance.
The number 108 is in itself a mandala. This wealth of synchronicity between the relationship of size and distance of the sun, moon, and earth and the structural dynamics of the psyche in framing the cosmos in mandala symbolism of 4s (north, south, east, west; sunrise, noon, sunset, midnight; etc) and 3s (trinities such as three poisons, three times, three treasures, three bodies of Buddha) makes 108 a number that signifies the identity of the objective with the subjective within differentiation which is the function of the mandala.