The concept of dualism is well illustrated by the Chinese pantheon. Whether as the result of the co-operation of the yin and the yang or of the final dissolution of P'an Ku, human beings came into existence. To the primitive mind the body and its shadow, an object and its reflection in water, real life and dream life, sensibility and insensibility (as in fainting, etc.), suggest the idea of another life parallel with this life and of the doings of the 'other self' in it. This 'other self,' this spirit, which leaves the body for longer or shorter intervals in dreams, swoons, death, may return or be brought back, and the body revive. Spirits which do not return or are not brought back may cause mischief, either alone, or by entry into another human or animal body or even an inanimate object and should therefore be propitiated. Hence worship and deification.