The eyes are round like gems, so that they can roll about and see things; the ears have holes in them so that they can hear; the nose has openings by which it can perceive smell; and the mouth is horizontal and slit so that it can inhale and exhale the breath; the tongue is like an organ reed so that it can make sounds and talk. Three of the four have each their particular office to fulfil, while the mouth has two offices. But the member that distinguishes the good from the bad is the heart, so that without the heart, even though you have eyes you cannot see, though you have ears you cannot hear, though you have a nose you cannot smell, and though you have a mouth you cannot breathe, so they say that without the heart "seeing you cannot see, and hearing you cannot hear."

YI Ryuk.