One day Monsieur Keuner was asked just what was meant by "reversal of perspective"; and he told the following story. Two brothers deeply attached to one another had a strange habit. They marked the nature of the day's events with pebbles a white one for each happy moment and a black one for each moment of misfortune or displeasure. But when, at the end of the day, they compared the contents of the jars one found only white pebbles and the other only black.

Fascinated by the persistence with which they lived the same experience differently, they both agreed to ask the advice of an old man famed for his wisdom. "You don't talk to one another enough" said the wise man, "Both of you must give the reasons for your choice, and discover its causes". From then on they did so, and soon discovered that while the first remained faithful to his white pebbles and the second to his black ones, in neither jar were there as many pebbles as before. Where there had been about thirty there were hardly more than seven or eight. After a short while they went to see the wise man again. Both looked extremely miserable. "Not so long ago," said one, "my jar was filled with pebbles the colour of the night. My despair was unbroken; I continued to live, I admit, only through the force of habit. Now I hardly ever collect more than eight pebbles, but what these eight signs of misery represent has become so intolerable that I cannot go on like this." And the other said: "Every day I piled up white pebbles.. Today there are only seven or eight, but these obsess me to the point that I cannot recall these moments of happiness without immediately wanting to relive them more intensely and, in a word, eternally. This desire torments me". The wise man smiled as he listened to them. "Excellent. Things are shaping up well. Keep at it. And one thing: whenever you can, ask yourselves why the game with the jar and the pebbles arouses so much passion in you." When the two brothers next saw the wise man it was to say "We asked ourselves the question but we could not find the answer. So we asked the whole village. You can see how much it has disturbed them. In the evening. squatting in front of their houses, whole families discuss the black and white pebbles. Only the elders and chieftains refuse to take part. They say a pebble is a pebble, and all are of equal value." The old man didn't conceal his pleasure. "Everything is developing as I foresaw. Don't worry. Soon the question will no longer be asked: it has lost its importance, and perhaps one day you will no longer believe you ever asked it." Shortly afterwards the old man's predictions were confirmed in the following way: a great joy overcame the members of the village; at the dawn of a troubled night, the rays of the sun fell upon the heads of the elders and chieftains, impaled upon the sharp-pointed stakes of the palisade.