THE meaning of the term Gnosis or Knowledge, as applied to a system of philosophy, may be illustrated by the language of Plato towards the end of the fifth book of the Republic, in which he distinguishes between knowledge and opinion as being concerned respectively with the real and the apparent. When to this distinction is added the further explanation that the objects of sense; the visible things of the world, belong to the class of phenomena and are objects of opinion, while the invisible essence of things, the one as distinguished from the many, is the true reality, discerned not by sense...