natural science took form. Physics, chemistry, astronomy,
geology, and the like describe the concrete world of matter and energy,
while the biological sciences deal with the structure, development,
interrelationships, and vital activities of animals and plants. Surely
knowledge has evolved with the advance in all of these subjects from
decade to decade and from year to year. And just as surely must evolution
continue, for the world has not stopped developing, and therefore the
great principles of science must undergo further changes, even though they
are the best summaries that can be formulated at the present time.

Philosophy deals with general conceptions of the universe. When we look
back through the ages we find men picturing the world as an aggregate of
diverse and uncorrelated elements--earth, air, fire, and water. The
synthesis of facts and the construction of general principles down through
Bacon, Newton, and Schopenhauer to modern world conceptions results in the
unification of all--"the choir of heaven and furniture 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 gr