Bold ideas, unjustified anticipations, and speculative thought, are our only means for interpreting nature: our only organon, our only instrument, for grasping her. And we must hazard them to win our prize. Those among us who are unwilling to expose their ideas to the hazard of refutation do not take part in the scientific game.

Ch. 10 "Corroboration, or How a Theory Stands up to Tests", section 85: The Path of Science, p. 280 - The Logic of Scientific Discovery (1934)