The vision of another world is ascribed to Er, the son of Armenius, who is said by Clement of Alexandria to have been Zoroaster. The tale has certainly an oriental character, and may be compared with the pilgrimages of the soul in the Zend Avesta (Haug, Avesta). But no trace of acquaintance with Zoroaster is found elsewhere in Plato’s writings, and there is no reason for giving him the name of Er the Pamphylian. The philosophy of Heracleitus cannot be shown to be borrowed from Zoroaster, and still less the myths of Plato.