Idols of the cave: There are biases in education. Everything that is taught is someone's opinion or interpretation of data.
Idols of the marketplace: The message of a writer is sometimes overshadowed by the words and expressions being used. Wording and such is effected by who the reader is because if they are lost then the message of the text cannot get through.
Idols of the theatre: most people tend to only promote the things that would benefit and assist them in some way. Everyone does something for a reason. There are no selfless good deeds, so its important to look where people are coming from before you jump right into believing what they are telling you.