Socrates describes how his follower Chaerephon journeyed to the oracles and Delphi and put to it the question of who was wisest. The oracle answered that none was wiser than Socrates. Socrates elucidates this response in Apology with an argument known as "Socratic ignorance". Socrates claims that he was initially puzzled by the oracle's claim because he did not consider himself wise. He took it as a sacred duty to talk to those who were reputed to be wise in Athens to investigate the oracle's claim. What he found was that many people who were considered wise or claimed to be wise were not, because they only knew examples and phenomena rather than essences and forms (i.e. they might be able to list virtuous acts, but they could not explain virtue itself). Eventually Socrates realized that the people who appeared wise were in fact not so, but they were deluded insofar as they were unaware of their own ignorance. Since Socrates knew his own ignorance, he was wiser than all others in just that one thing, the knowing of the limits of his knowledge.