CAN YOU SWIM

In the old times there were only rowboats to cross the straits of Bosporus in Turkey, not the large boats of today. If you wanted to go from one side to the other, you hired a boat with five or ten other people and paid the boatman to take you across.
One day, a professor of geography stepped into one of these boats to cross the straits. Just as the boat set out, the wind started to kick up, and the boat began to sway from side to side.
As they made their way across the straits, the professor asked the boatman, "Do you know geography?"
The boatman replied that he did not. The professor said, "You've wasted one third of your life. A third of your life is gone."
A few moments later, the professor asked, "Do you know math?" and the boatman replied that he did not. Again the professor said, "A third of your life is gone; you've wasted all of this time."
Then he asked him, "Do you know history? No? A third of your life is gone; you have wasted so much time." and continued berating the boatman like this.
Mean while, the wind had become quite ferocious and the boat to rock back and forth wildly.
The boatman asked the professor "Do you know how to swim?"
The professor replied that he did not. The boatman said to him, "Then all of your life is gone."

REFERENCE: WHAT ABOUT MY WOOD BY ES- SEYYID ES-SHAYKH