The Doctrine of Evolution | Page 2

accusation is often only too well merited that I have endeavored to
show as well as circumstances permit how universal is the scope of the
doctrine based upon the facts of biology, and how supreme are its
practical and dynamic values.
It remains only to state that the present volume contains nothing new,
either in fact or in principle; the particular form and mode of presenting
the evolutionary history of nature may be considered as the author's
personal contribution to the subject. Nothing has been stated that has
not the sanction of high authority as well as of the writer's own
conviction; but it will be clear that the believers in the truth of the
analysis as made in the later chapters may become progressively fewer,
as the various aspects of human life and of human nature are severally
treated. Nevertheless, I believe that this volume presents a consistent
reasonable view that will not be essentially different from the
conceptions of all men of science who believe in evolution.

CONTENTS

CHAPTER PAGE
I. EVOLUTION. THE LIVING ORGANISM AND ITS NATURAL
HISTORY 1
II. THE STRUCTURE AND DEVELOPMENT OF ANIMALS AS
EVIDENCE OF EVOLUTION 35
III. THE EVIDENCE OF FOSSIL REMAINS 73
IV. EVOLUTION AS A NATURAL PROCESS 106
V. THE PHYSICAL EVOLUTION OF THE HUMAN SPECIES AND
OF HUMAN RACES 150
VI. THE MENTAL EVOLUTION OF MAN 197
VII. SOCIAL EVOLUTION AS A BIOLOGICAL PROCESS 241
VIII. EVOLUTION AND THE HIGHER HUMAN LIFE 278
INDEX 313

I
EVOLUTION. THE LIVING ORGANISM AND ITS NATURAL
HISTORY
The Doctrine of Evolution is a body of principles and facts concerning
the present condition and past history of the living and lifeless things
that make up the universe. It teaches that natural processes have gone
on in the earlier ages of the world as they do to-day, and that natural
forces have ordered the production of all things about which we know.
It is difficult to find the right words with which to begin the discussion

of so vast a subject. As a general statement the doctrine is perhaps the
simplest formula of natural science, although the facts and processes
which it summarizes are the most complex that the human intellect can
contemplate. Nothing in natural history seems to be surer than
evolution, and yet the final solution of evolutionary problems defies the
most subtle skill of the trained analyst of nature's order. No single
human mind can contain all the facts of a single small department of
natural science, nor can one mind comprehend fully the relations of all
the various departments of knowledge, but nevertheless evolution
seems to describe the history of all facts and their relations throughout
the entire field of knowledge. Were it possible for a man to live a
hundred years, he could only begin the exploration of the vast domains
of science, and were his life prolonged indefinitely, his task would
remain forever unaccomplished, for progress in any direction would
bring him inevitably to newer and still unexplored regions of thought.
Therefore it would seem that we are attempting an impossible task
when we undertake in the brief time before us the study of this
universal principle and its fundamental concepts and applications. But
are the difficulties insuperable? Truly our efforts would be foredoomed
to failure were it not that the materials of knowledge are grouped in
classes and departments which may be illustrated by a few
representative data. And it is also true that every one has thought more
or less widely and deeply about human nature, about the living world to
which we belong, and about the circumstances that control our own
lives and those of our fellow creatures. Many times we withdraw from
the world of strenuous endeavor to think about the "meaning of things,"
and upon the "why" and "wherefore" of existence itself. Every one
possesses already a fund of information that can be directly utilized
during the coming discussions; for if evolution is true as a universal
principle, then it is as natural and everyday a matter as nature and
existence themselves, and its materials must include the facts of daily
life and observation.
Although the doctrine of evolution was stated in very nearly its present
form more than a century ago, much misunderstanding still exists as to
its exact meaning and nature and value; and it is one of the primary

objects of these discussions to do away with certain current errors of
judgment about it. It is often supposed to be a remote and recondite
subject, intelligible only to the technical expert in knowledge, and apart
from the everyday world of life. It is more often conceived as a
metaphysical and philosophical system, something antagonistic to the
deep-rooted religious instincts and the theological beliefs of mankind.
Truly all the facts of knowledge