Swamiji in Class 226 of Bagawat Geeta:
There are four types of people:
- He who knows not and not knows knows not; fool
- He who knows not and who knows knows not; ignorant; teach him
- He who knows and knows not he knows; very intelligent but does not know he is intelligent; wake him
- He who knows and knows he knows; very intelligent; follow him.
Vedas add one more variety – tamasic – he who knows not and thinks he knows.