numerology

What is so magical about the decimal number system? Why is the number ten so important? It must be deeper than the number of fingers on our two hands: there are so many areas of ancient and/or mystical teachings that rely on groupings of the order of ten (the most obvious in my mind being the Kabbalistic Tree of Life). The one of particular interest for this article, however, is a system that arose in the last century. It may be much more ancient, but I have not determined its origins. I am referring to the numerological system of "life purpose" as revealed by Dan Millman in The Life You Were Born to Live.