Schopenhauer in Die Welt refers to the Vedanta in Die Welt; and in one specific passage he declares: 'It is Maya, the veil of deception, which blinds the eyes of mortals and makes them behold a world of which they cannot say that it is or that it is not: for it is like a dream; it is like the sunshine on the sand which the traveller from afar takes to be water; or the stray piece of rope he takes for a snake'. This he declares appears in 'innumerable' passages in the Vedas and the Puranas; is there a specific passage in say the Upanishads that can be cited as a specific reference, that can be considered as the ur-reference? And is it wrong to take the Upanishads in preference to the Puranas?