One day, Socrates was walking about in the marketplace. An acquaintance rushed up to the great philosopher and said excitedly, "Do you know what I just heard about your friend?"
"Hold on awhile", Socrates replied. "Before telling me anything did you put it trough the three sieves?"
"And what are those?", the man asked.
"Well, it is a little test I have. Let us try it on what you are going to say about my friend," said Socrates.
The philosopher then explained: "The first sieve is the one of Truth. Did you make sure what you are about to tell me is true?"
"Not exactly. I just overheard it," the man replied.
"So you don't really know if it is true or not. Then you must have used the second sieve, the one of Goodness!", exclaimed Socrates, "Is what you are about to tell me something good about my friend?"
"Actually, it is the opposite," said the man sheepishly.
"So you want to tell me something bad about my friend, but you are not certain if it is true. There is a third sieve left in our test still --- the sieve of Usefulness," Socrates went on, "Have you examined what you are about to say is useful?"
"No, not really," the man admitted.
"Well," Socrates concluded, "If what you are about to tell me is neither true, nor good, nor even useful, then why bother telling it to me at all? Forget it!"
The man left. He had just learnt a lesson in wisdom from the wisest of men.