Let it be understood, at the outset, that every proved theory of science is to be accepted. Only the most intense prejudice and the maddest folly would lead any one to reject the proved conclusions of science. Moreover, we should examine any new hypothesis with open minds, to see if it has in it anything truthful, helpful or advantageous. It should neither be accepted nor rejected simply because it is new. But if a theory is evidently or probably untrue, or pernicious, or at all harmful, it is to be rejected and condemned.