“An idea that is not dangerous is not worthy of being called an idea at all.”

“"Dangerous" does not mean exciting or bold; it means likely to cause great harm. The most dangerous idea is the only dangerous idea: The idea that ideas can be dangerous.”

“All great ideas are dangerous.”

“My ultimate intuitive clue in philosophy is that "God is love" and that the idea of God is definable as that of the being worthy to be loved with all one’s heart, mind, soul, and entire being.”

“Not all ideas of the ideas that pass from one brain to another brain... are good ideas; some are mistakes. These I call 'mismemes.'”

“Yes, books are dangerous. They should be dangerous - they contain ideas.”

“Nothing is more dangerous than an idea, when you have only one idea.”

“All told it is a new world. It calls for new ideas. In Canada it calls for a New Party.”

“No weapon is as dangerous as an idea. A weapon will kill you in that moment. A bad idea can kill you for a lifetime.”