One of the most interesting issues dealt with in metaphysics as a branch of philosophy right from the time sages in different parts of the world began to philosophise in antiquity is the question of appearance and reality. In thinking about the subject, philosophers use it to signify a contrast between the world of "mere appearance" usually considered to be nothing more than a reflection or shadow of something greater, with what is real and, therefore, probably of more value and permanent. It is claimed further that when the "really real" is cognised as such, it serves as the foundation of wisdom and knowledge.