This principle, since that day, has been thoroughly worked out in practically all the important fields of both the plant and animal world.  Moreover, the doctrine of evolution, dependent upon this principle, has exerted so great an influence upon the process of investigation and thinking in all fields of activity that the resulting change in method has amounted to a revolution.  The principle is applied not only in the field of biology, but also in the realm of astronomy, where we study the evolution of worlds, and in psychology, history, social science, where we speak of the development of human traits and of the growth of economic, political and social institutions.

It is necessary to remember in applying such a brief statement of a principle, that the words are used in a highly technical sense.  The word “fittest” by no means need imply the best from the point of view of beauty or strength or usefulness in nature; nor does it necessarily mean, in reference to society, best from the point of view of morals or a higher civilization.  Rather the “fittest” means the being best adapted to the conditions under which it is living, or to its environment.  As a matter of fact, it is the general opinion that in practically all fields this principle works toward progress in the highest and best sense; but it is always a matter for specific study as well as of great scientific interest and importance, to determine where and how the variation and the corresponding selection tend to promote the morally good.  Especially is this true in the study of society, where we should endeavor to see whether or not the “fittest” means also the highest from the moral and religious point of view.

The story of the flood gives us a most interesting example of the way in which the ancient Hebrews looked upon such a process of selection in the moral and religious world and taught it as a divine principle.  It is, therefore, one of the most suggestive and interesting of the writings of the early Israelites.

VI.

THE SURVIVAL OF THE FITTEST IN SOCIAL AND POLITICAL LIFE.

From our modern point of view, the ancient Hebrew writers had a far deeper knowledge of moral and religious questions than of natural science.  They had a far keener sense of what was socially beneficial than of what was scientifically true.  However we may estimate their knowledge of geology and biology, we must grant that their beliefs regarding the good and ill effects of human action have in them much that is universally true, even though we may not follow them throughout in their theories of divine wrath and immediate earthly punishment of the wicked.