The advances in the realm of pure intellect have been of equal note, and they have been both intensive and extensive.  Great virgin fields of learning and wisdom have been discovered by the few, and at the same time knowledge has spread among the many to a degree never dreamed of before.  Old men among us have seen in their own generation the rise of the first rational science of the evolution of life.  The astronomer and the chemist, the psychologist and the historian, and all their brethren in many different fields of wide endeavor, work with a training and knowledge and method which are in effect instruments of precision, differentiating their labors from the labors of their predecessors as the rifle is differentiated from the bow.

The play of new forces is as evident in the moral and spiritual world as in the world of the mind and the body.  Forces for good and forces for evil are everywhere evident, each acting with a hundred- or a thousand-fold the intensity with which it acted in former ages.  Over the whole earth the swing of the pendulum grows more and more rapid, the main-spring coils and spreads at a rate constantly quickening, the whole world movement is of constantly accelerating velocity.

In this movement there are signs of much that bodes ill.  The machinery is so highly geared, the tension and strain are so great, the effort and the output have alike so increased, that there is cause to dread the ruin that would come from any great accident, from any breakdown, and also the ruin that may come from the mere wearing out of the machine itself.  The only previous civilization with which our modern civilization can be in any way compared is that period of Graeco-Roman civilization extending, say, from the Athens of Themistocles to the Rome of Marcus Aurelius.  Many of the forces and tendencies which were then at work are at work now.  Knowledge, luxury, and refinement, wide material conquests, territorial administration on a vast scale, an increase in the mastery of mechanical appliances and in applied science—­all these mark our civilization as they marked the wonderful civilization that flourished in the Mediterranean lands twenty centuries ago; and they preceded the downfall of the older civilization.  Yet the differences are many, and some of them are quite as striking as the similarities.  The single fact that the old civilization was based upon slavery shows the chasm that separates the two.  Let me point out one further and very significant difference in the development of the two civilizations, a difference so obvious that it is astonishing that it has not been dwelt upon by men of letters.