From The Forerunner by Khalil Gibran
Four frogs sat upon a log that lay floating on the edge of a river. Suddenly the log was caught by the current and swept slowly down the stream. The frogs were delighted and absorbed, for never before had they sailed.
At length the first frog spoke, and said, “This is indeed a most marvelous log. It moves as if alive. No such log was ever known before.” Then the second frog spoke, and said, “Nay, my friend, the log is like other logs, and does not move. It is the river that is walking to the sea, and carries us and the log with it.” And the third frog spoke, and said, “It is neither the log nor the river that moves. The moving is in our thinking. For without thought nothing moves.” And the three frogs began to wrangle about what was really moving. The quarrel grew hotter and louder, but they could not agree.
Then they turned to the fourth frog, who up to this time had been listening attentively but holding his peace, and they asked his opinion. And the fourth frog said, “Each of you is right, and none of you is wrong. The moving is in the log and the water and our thinking also.”
And the three frogs became very angry, for none of them was willing to admit that his was not the whole truth, and that the other two were not wholly wrong. Then a strange thing happened. The three frogs got together and pushed the fourth frog off the log into the river.
http://www-personal.umich.edu/~jrcole/gibran/forerun/fore.htm#Knowledge and Half-knowledge