of a new conception of the universe, the fitting of a new alphabet to the old Morse code—a proceeding which we call the acquirement of knowledge—we can and do change to a marked extent our way of seeing things: building up new worlds from old sense impressions, and transmuting objects more easily and thoroughly than any magician. “Eyes and ears,” said Heracleitus, “are bad witnesses to those who have barbarian souls”: and even those whose souls are civilized tend to see and hear all things through