How Can You Say That Material Knowledge Is Useless

“When Prahlada Maharaja was asked by his father to say something from whatever he had learned, he considered that what he had learned from his spiritual master was the best of all teachings whereas what he had learned about diplomacy from his material teachers, Shanda and Amarka, was useless.” (Shrila Prabhupada, 7.5.23-24 Purport)