Source: Conjectures and Refutations: The Growth of Scientific Knowledge (1963), Ch. 1 "Science : Conjectures and Refutations"
Context: The history of science, like the history of all human ideas, is a history of irresponsible dreams, of obstinacy, and of error. But science is one of the very few human activities — perhaps the only one — in which errors are systematically criticized and fairly often, in time, corrected. This is why we can say that, in science, we often learn from our mistakes, and why we can speak clearly and sensibly about making progress there.
