In ancient Greece, Socrates was reputed to hold knowledge in high esteem.
One day, an acquaintance ran up to the great philosopher and said, "Socrates, do you know what I just heard
about your friend?"
"Hold on a minute," Socrates replied.
"Before telling me anything I'd like you to pass a little test. It's called the Triple Filter Test."
"Triple filter?"
"That's right," Socrates continued. "Before you talk to me
about my friend, it might be a good idea to take a moment and filter what you're going to say. The first filter is
Truth. Have you made absolutely sure that what you are
about to tell me is true?"
"No," the man said, "actually I just heard
about it..."
"All right," said Socrates. "So you don't really know if it's true or not. Now let's try the second filter, the filter of Goodness. Is what you are
about to tell me
about my friend something good?"
"No, on the contrary..."
"So," Socrates continued, "you want to tell me something bad
about him, but you're not certain it's true. You may still pass the test though because there's
one filter left: the filter of Usefulness. Is what you want to tell me
about my friend going to be something I can use to benefit the world?"
"No, not really."
"Well," concluded Socrates, "if what you want to tell me is neither true nor good nor even useful, why tell it to me at all?"
The man stared at him, and without a word
turned around and left, dejected.
This is why Socrates was a great philosopher and held in such high esteem.
It also explains why he never found out his best friend was sleeping with his wife.