The difficulty lies not so much in developing new ideas as in escaping from old ones.

The difficulty lies, not in the new ideas, but in escaping the old ones, which ramify, for those brought up as most of us have been, into every corner of our minds.

The ideas of economists and political philosophers, both when they are right and when they are wrong are more powerful than is commonly understood. Indeed, the world is ruled by little else. Practical men, who believe themselves to be quite exempt from any intellectual influences, are usually slaves of some defunct economist.

Ideas shape the course of history.

The power of vested interests is vastly exaggerated compared with the gradual encroachment of ideas

I can't understand why people are frightened of new ideas. I'm frightened of the old ones.