One thing only I know

Socrates himself said, "One thing only I know, and that is that I know nothing."
An Athenian is said to have asked the oracle at Delphi who the wisest man in Athens was. The oracle answered that Socrates of all mortals was the wisest. When Socrates heard this he was astounded, to put it mildly. He went straight to the person in the city whom he, and everyone else, thought was excessively wise. But when it turned out that this person was unable to give Socrates satisfactory answers to this questions, Socrates realised that the oracle had been right.