To kill an error is as good a service as, and sometimes even better than, the establishing of a new truth or fact.

Darwin’s remark elevates the negative work of science—refuting mistaken ideas—to the same rank as discovery. Progress is not only additive (new facts) but corrective: clearing away false assumptions can unblock whole lines of inquiry, prevent wasted effort, and sharpen methods of observation and inference. The phrase also reflects a mature scientific temperament: intellectual humility and a willingness to let cherished explanations die when evidence demands it. In Darwin’s own milieu of Victorian natural history, where broad theories competed and evidence was uneven, the disciplined elimination of error was often the precondition for any stable “truth” to emerge.