age could do was to note a few striking resemblances and differences among the animals that roamed the neighboring forests. What could be done in the later age, ay, what the scientific temper of the age demanded, was the most rigidly careful examination of multitudes of facts; examination by a trained mind and with all the improved appliances which science and art had given to the world, and then submitted to the searching scrutiny of other trained minds, with like appliances. Or take the last step, verification. In one case it meant finding the effect upon the taste and upon the health. In the other, what it meant may be judged from the account we have of one of Newton's investigations. In applying his hypothesis of gravitation (it was only a hypothesis then) to the motion of the moon, there was a very slight divergence, about two feet a minute, between the time of the revolution of the moon in its orbit, as he calculated it and as he observed it. He was not satisfied until, eighteen years after, on account of an improvement made in the method of taking observations, he was able to obtain what he regarded as a verification.
And so what we learn from the history of science is the gradual development of scientific method. Scientific method in the work of Hipparchus meant a very different thing from the scientific method of the Chaldeans. Very different still is the scientific method of studying the heavens to-day. So to an even greater degree is there a difference between the scientific method of studying the earth today and as our fathers studied it. It is not merely the multitude of facts that we have learned, nor the marvelous instruments that we have made to aid us in our observations; it is also, and by no means least, this—that men all these centuries have been learning to observe, to reason, and to verify.
We may say that science and scientific method have grown and developed together: the development of one has invariably advanced the development of the other, and, on the other hand, where one has remained stationary, or has retrograded, so has the other.
History has enabled us to see this other fact also: that the conditions which interfered with the growth of science in the past not only interfere with it always, wherever they exist, but to very much the same degree interfere with the free application of scientific method. What those conditions were during one long period of history we saw—a failure to realize its importance as compared with questions of conduct; a tendency to comment rather than investigate; a tendency to ascribe everything to spiritual agency rather than to natural causes; and lastly, dogmatism. We very well know how, as a matter of fact, those very conditions do interfere with the application of scientific method to-day.
