The ancient Japanese did not strictly divide their world into the material and the spiritual, nor between this world and another perfect realm, but their intuitive spirituality infused all domains. There is an underlying belief of the early Shinto world-view, that is, continuity between man and nature. This concept is also encapsulated by the Japanese word nagare, meaning ‘flow’, and leads to the conception of vital connections between the divine nature of the kami, and by extension the natural world, and humanity (through respectful rituals); between post-mortem souls and the living (such as the ie construct which is an extended sense of family); and between the inner and outer worlds (as found in ideas about pollution and purity).
(Paraphrased from Lucy Wright)