Imam Shafi’ee would say: There are four types of people in this world that you may encounter in a debate:
1) One who knows not, and knows he knows not – he is a student. Teach that person.
2) One who knows, and others know he knows – is a teacher. Learn from that person.
3) One who knows, and knows not that he knows – is humble. Encourage him.
4) One who knows not, and doesn’t know that he knows not – he is Fool. Avoid that person.