Non Duality

What is meant by non duality, Mahatmi? It means that light and shade, long and short, black and white, can only be experienced in relation to each other; light is not independent of shade, nor black of white. There are no opposites, only relationships. In the same way, nirvana and the ordinary world of suffering are not two things but related to each other. There is no nirvana except where the world of suffering is; there is no world of suffering apart from nirvana. For existence is not mutually exclusive. - Lankavatara Sutra