What is the Scientology cross?
It is an eight-pointed cross representing the eight parts, or dynamics, of life through which each individual is striving to survive. These parts are: the urge toward existence as self, as an individual; the urge to survive through creativity, including the family unit and the rearing of children; the urge to survive through a group of individuals or as a group; the urge toward survival through all Mankind and as all Mankind; the urge to survive as life forms and with the help of life forms such as animals, birds, insects, fish and vegetation; the urge to survive of the physical universe, by the physical universe itself and with the help of the physical universe and each one of its component parts; the urge to survive as spiritual beings or the urge for life itself to survive; the urge toward existence as infinity, also identified as the Supreme Being. To be able to live in harmony with respect to each of these spheres of existence is symbolized by the Scientology cross.
As a matter of interest, the cross as a symbol predates Christianity.