The Triple Filter Test

 In ancient Greece, Socrates was reputed to hold knowledge in
 high esteem. One day an acquaintance met the great philosopher
 and said, "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. That's why I call it the triple filter test.
 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 and..."

   "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 useful to me?"

   "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?"