…when a friend stopped him and said “My friend, I must tell you something bad I heard about one of your students.”
Plato said, “First answer me the three tests of knowledge. One, have you personally checked if this thing is true?” “No” the friend answered. “Then two,” said Plato, “Will this knowledge make me happier?” “No”. came the reply. “Then there is one final test to determine if I need this knowledge my friend.” said the master. ” Is it to my students’ advantage that I know it?” “Alas no.” came the reply.
“Then pass on your way my friend and do not tell me this thing.” said Plato and walked off smiling. This is why he was the greatest Philosopher of all, and also why he never found out that Aristotle was shagging his wife.