A grammarian once embarked in a boat.  Turning to the boatman with a self-satisfied air he asked him:
  'Have you ever studied grammar?'
  'No,' replied the boatman.
  'Then half your life has gone to waste,' the 
grammarian said.
  The boatman thereupon felt very depressed, but he answered him nothing for the moment.  Presently the wind tossed the boat into a whirlpool.  The boatman shouted to the grammarian:
  'Do you know how to swim?'
  'No,' the grammarian replied, 'my well-spoken, handsome fellow.'
  'In that case, grammarian,' the boatman remarked, 'the whole of your life has gone to waste, for the boat is sinking in these whirlpools.'

  You may be the greatest scholar in the world in you time, but consider, my friend, how the world passes away - and time!

("The Grammarian and the Boatman" translated by A. J. Arberry, Rumi, printed 2006)