What is the theme in Intellectuals by Paul Johnson?

One dominant theme of the book is man's belief that he could change the world based on his own beliefs. This is pretty much what philosophy and intellectualism are all about. Each of the intellectuals discussed in the book felt that he could change society by the product of their own intellect, whether it was through philosophy, drama, books or publishing. Each felt that their views should be adhered to by other people. They were egotists in that they felt that their views and opinions should be listened to. Most did little research and distorted facts.