oups, 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.

Every one can find something worth while in the lessons of evolution,
summarized in the foregoing statements. The atheist, who declines to
personify the ultimate powers of the universe, may, nevertheless, find
direction for his life in the principles brought to light by science. The
agnostic, who doubts the validity of many conventional dicta that may not
seem well grounded, can also find something to believe and to obey.
Finally, the orthodox theist of whatever creed may discover cogent reasons
for many of his beliefs like the Golden Rule previously accepted through
convention; and he must surely welcome the fuller knowledge of their sound
basis in the materials and results of comparative analyt