In traditional Chinese philosophy, human life is believed to be connected to nature, which is thought of as the foundation and encompassing force sustaining all of life's phases. Passing and coming of the seasons, life, birth and death are perceived as a cyclic and perpetual occurrences that are believed to be regulated by the principles of "yin" and "yang""." When one dies, the life-giving material force referred to as "ch'i", encompassing both body and spirit, rejoins the material force of the universe and cycles on with respect to the rhythms set forth by "yin" and "yang."