Karl Popper

"No rational argument will have a rational effect on a man who does not want to adopt a rational attitude."

"We must plan for freedom, and not only for security, if for no other reason than that only freedom can make security secure."

"Our knowledge can only be finite, while our ignorance must necessarily be infinite."

"Science may be described as the art of systematic over-simplification."

"Science must begin with myths, and with the criticism of myths."

"Piecemeal social engineering resembles physical engineering in regarding the ends as beyond the province of technology."