of earth.”  The lineal descendant of the long line of ancestral philosophies is the monism which sees no difference between the living and lifeless worlds save that of varying combinations of ultimate elements which are conceived as uniform “mind-stuff” everywhere.  Whether or not this universal conception of totality is true, remains for the future to show.  For us the important truth is that here, as in all other departments of knowledge, evolution proves to be real.

* * * * *

In closing the present description of the basis, nature, and scope of the doctrine of evolution, I find great difficulty in choosing the right words for a concise statement of the larger values and results of this department of science.  So much might be said, and yet it is not fitting for the investigator to preach unduly.  The lessons of the doctrine must be brought home to each individual through personal conviction.  But because I firmly believe in the truth of the statement made in the opening pages, namely, that science and its results are of practical human value, it is in a sense my duty as an advocate of evolution to make this plain.

The method of science is justified of its fruits.  At the very beginning we learned how, and how only, sure knowledge can be obtained and how it differs from a belief which may or may not correspond with the truth.  Based upon facts of smaller or larger groups, scientific laws are so many summaries of past experience, and they describe in concise conceptual shorthand the manifold happenings of nature.  Their difference from belief inheres in their ability to serve as guides for everyday and future experience.  This entire volume is a plea for the employment of common-sense as we look upon and interpret the world in which we have our places and in which we must play our roles.  Our search for truth will be rewarded in so far as we organize our common-sense observations into clear conceptions of the laws of nature’s order.

The doctrine of evolution enjoins us to learn the rules of the great game of life which we must play, as science reveals them to us.  It is well to remember that a little knowledge is a dangerous thing, but because evolution is true always and everywhere, an understanding of its workings in any department of thought and life clears the vision of other realms of knowledge and action.  Perhaps the greatest lesson is at the same time the most practical one.  It is that, however much we may concern ourselves with ultimate matters, our immediate duties are here and now, and we cannot escape them without giving up our right to a place in nature.  We are taught by science that we live under the control of certain fundamental biological, social, and ethical laws; we might well wish that they were otherwise, but having recognized them we have no recourse save to obey them.  Evolution as a complete doctrine commands every one to live a life of service as full as hereditary endowments and surrounding circumstances will permit.  Thus we are taught that the immediate problems of life ought to concern us more than questions as to the ultimate nature of the universe and of existence.