All philosophies have recognized the duality in nature. However much we may differ on the surface as to principles and opinions, those who go below the surface, the divers for truth, have always found the same things. The Vedanta calls the two forces purusha and prakriti, the creator and the created, the creative and the responsive forces, by which the whole manifestation has been made. In the religious language it is called Shiva and Parvati. In the Hindu inscriptions and books you can see the picture of Shiva, with two faces, a man's face and a woman's face, showing the creative force and the responsive force that Shiva possessed. There are many other pictures in these inscriptions, pictures such as that of an animal's body with a man's head, of which the meaning is that man's body is animal; it is his head that is man.