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Columbia University Lectures

THE DOCTRINE OF EVOLUTION

THE HEWITT LECTURES

1906-1907

COLUMBIA UNIVERSITY PRESS
SALES AGENTS

NEW YORK:
LEMCKE & BUECHNER
30-32 WEST 27TH STREET

LONDON:
HUMPHREY MILFORD
AMEN CORNER, E.C.


_COLUMBIA UNIVERSITY LECTURES_

THE DOCTRINE OF EVOLUTION

ITS BASIS AND ITS SCOPE

BY

HENRY EDWARD CRAMPTON, PH.D.

PROFESSOR OF ZOÖLOGY, COLUMBIA UNIVERSITY


New York

COLUMBIA UNIVERSITY PRESS

1916

_All rights reserved_

COPYRIGHT, 1911,

By THE COLUMBIA UNIVERSITY PRESS

Set up and electrotyped. Published June, 1911.
Reprinted December, 1912; September, 1916.

Norwood Press
J.S. Cushing Co. - Berwick & Smith Co.
Norwood, Mass., U.S.A.




PREFACE


The present volume consists of a series of eight addresses delivered as
the Hewitt Lectures of Columbia University at Cooper Union in New York
City during the months of February and March, 1907. The purpose of these
lectures was to describe in concise outline the Doctrine of Evolution, its
basis in the facts of natural history, and its wide and universal scope.
They fall naturally into two groups. Those of the first part deal with
matters of definition, with the essential characteristics of living
things, and, at greater length, with the evidences of organic evolution.
The lectures of the second group take up the various aspects of human
evolution as a special instance of the general organic process. In this
latter part of the series, the subject of physical evolution is first
considered, and this is followed by an analysis of human mental evolution;
the chapter on social evolution extends the fundamental principles to a
field which is not usually considered by biologists, and its purpose is to
demonstrate the efficiency of the genetic method in this department as in
all others; finally, the principles are extended to what is called "the
higher human life," the realm, namely, of ethical, religious, and
theological ideas and ideals.

Naturally, so broad a survey of knowledge could not include any extensive
array of specific details in any one of its divisions; it was possible
only to set forth some of the more striking and significant facts which
would demonstrate the nature and meaning of that department from which
they were selected. The illustrations were usually made concrete through
the use of photographs, which must naturally be lacking in the present
volume. In preparing the addresses for publication, the verbal form of
each evening's discussion has been somewhat changed, but there has been no
substantial alteration of the subjects actually discussed.

The choice of materials and the mode of their presentations were
determined by the general purpose of the whole course. The audiences were
made up almost exclusively of mature persons of cultivated minds, but who
were on the whole quite unfamiliar with the technical facts of natural
history. It was necessary to disregard most of the problematical elements
of the doctrine so as to bring out only the basic and thoroughly
substantiated principles of evolution. The course was, in a word, a simple
message to the unscientific; and while it may seem at first that the
discussions of the latter chapters lead to somewhat insecure positions, it
should be remembered that their purpose was to bring forward the proof
that even the so-called higher elements of human life are subject to
classification and analysis, like the facts of the lower organic world.

It may seem that the biologist is straying beyond his subject when he
undertakes to extend the principles of organic evolution to those
possessions of mankind that seem to be unique. The task was undertaken in
the Hewitt Lectures because the writer holds the deeply grounded
conviction that evolution has been continuous throughout, and that the
study of lower organic forms where laws reveal themselves in more
fundamental simplicity must lead the investigator to employ and apply
those laws in the study of the highest natural phenomena that can be
found. Another motive was equally strong. Too frequently men of science
are accused of restricting the application of their results to their own
particular fields of inquiry. As individuals they use their knowledge for
the development of world conceptions, which they are usually reluctant to
display before the world. It is because I believe that the 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 are the materials of science, but science is not metaphysics or
philosophy or belief, even though the student who employs scientific
method is inevitably brought to consider problems belonging to these
diverse fields of thought. A study of nervous mechanism and organic
structure leads to the philosophical problem of the freedom of the will;
questions as to the evolution of mind and the way mind and matter are
related force the investigator to consider the problem of immortality. But
these and similar subjects in the field of extra-science are beyond its
sphere for the very good reason that scientific method, which we are to
define shortly, cannot be employed for their solution. Evolution is a
science; it is a description of nature's order, and its materials are
facts only. In method and content it is the very science of sciences,
describing all and holding true throughout each one.

The overwhelming importance of knowing about natural laws and universal
principles is not often realized. What have we to do with evolution and
science? Are we not too busy with the ordering of our immediate affairs to
concern ourselves with such remote matters? So it may appear to many, who
think that the study of life and its origin, and of the vital facts about
plants and animals may be interesting and may possess a certain
intellectual value, but nothing more. The investigation of man and of men
and of human life is regarded by the majority as a mere cultural exercise
which has no further result than the recording of present facts and past
histories; but it is far otherwise. Science and evolution must deal with
mere details about the world at large, and with human ideals and with life
and conduct; and while their purpose is to describe how nature works now
and how it has progressed in the past, their fullest value is realized in
the sure guidance they provide for our lives. This cannot be clear until
we reach the later portions of our subject, but even at the outset we must
recognize that knowledge of the great rules of nature's game, in which we
must play our parts, is the most valuable intellectual possession we can
obtain. If man and his place in nature, his mind and social obligations,
become intelligible, if right and wrong, good and evil, and duty come to
have more definite and assignable values through an understanding of the
results of science, then life may be fuller and richer, better and more
effective, in direct proportion to this understanding of the harmony of
the universe.

And so we must approach the study of the several divisions of our subject
in this frame of mind. We must meet many difficulties, of which the chief
one is perhaps our own human nature. For we as men are involved, and it is
hard indeed to take an impersonal point of view, - to put aside all
thoughts of the consequences to us of evolution, if it is true. Yet
emotion and purely human interest are disturbing elements in intellectual
development which hamper the efforts of reason to form assured
conceptions. We must disregard for the time those insistent questions as
to higher human nature, even though we must inevitably consider them at
the last. Indeed, all the human problems must be put aside until we have
prepared the way for their study by learning what evolution means, what a
living organism is, and how sure is the evidence of organic
transformation. When we know what nature is like and what natural
processes are, then we may take up the questions of supreme and deep
concern about our own human lives.

* * * * *

Human curiosity has ever demanded answers to questions about the world and
its make-up. The primitive savage was concerned primarily with the
everyday work of seeking food and building huts and carrying on warfare,
and yet even he found time to classify the objects of his world and to
construct some theory about the powers that made them. His attainments may
seem crude and childish to-day, but they were the beginnings of classified
knowledge, which advanced or stood still as men found more or less time
for observation and thought. Freed from the strife of primeval and
medieval life, more and more observers and thinkers have enlarged the
boundaries and developed the territory of the known. The history of human
thought itself demonstrates an evolution which began with the savages'
vague interpretation of the "what" and the "why" of the universe, and
culminates in the science of to-day.

What, now, is a science? To many people the word denotes something cold
and unfeeling and rigid, or something that is somehow apart from daily
life and antagonistic to freedom of thought. But this is far from being
true. Karl Pearson defines science as _organized knowledge_, and Huxley
calls it _organized common sense_. These definitions mean the same thing.
They mean that in order to know anything that deserves confidence, in
order to obtain a real result, it is necessary in the first place to
establish the reality of facts and to discriminate between the true, the
not so sure, the merely possible, and the false. Having accurate and
verified data, scientific method then proceeds to classify them, and this
is the _organizing_ of knowledge. The final process involves a summary of
the facts and their relations by some simple expression or formula. A good
illustration of a scientific principle is the natural law of gravitation.
It states simply that two bodies of matter attract one another directly in
proportion to their mass, and inversely in proportion to the square of the
distance between them. In this concise rule are described the relations
which have been actually determined for masses of varying sizes and at
different distances apart, - for snowflakes falling to the earth, for the
avalanche on the mountain slope, and for the planets of the solar system,
moving in celestial coördination.

Such a principle as the law of gravitation, like evolution, is true if the
basic facts are true, if they are reasonably related, and if the
conclusion is drawn reasonably from them. It is true for all persons who
possess normal minds, and this is why Huxley speaks of science as "common
sense," - that is, something which is a reasonable and sensible part of the
mental make-up of thinking persons that they can hold in common. The form
and method of science are fully set forth by these definitions, and the
purpose also is clearly revealed. For the results of investigation are not
merely formulæ which summarize experience as so much "conceptual
shorthand," as Karl Pearson puts it, but they must serve also to describe
what will probably be the orderly workings of nature as future experience
unfolds. Human endeavor based upon a knowledge of scientific principles
must be far more reliable than where it is guided by mere intuition or
unreasoned belief, which may or may not harmonize with the everyday world
laws. Just as the law of gravitation based upon past experience provides
the bridge builder and the architect with a statement of conditions to be
met, so we shall find that the principles of evolution demonstrate the
best means of meeting the circumstances of life.

Evolution has developed, like all sciences, as the method we have
described has been employed. Alchemy became chemistry when the so-called
facts of the medievalist were scrutinized and the false were discarded.
Astrology was reorganized into astronomy when real facts about the planets
and stars were separated from the belief that human lives were influenced
by the heavenly bodies. Likewise the science of life has undergone
far-reaching changes in coming down to its present form. All the principles
of these sciences are complete only in so far as they sum up in the best
way the whole range of facts that they describe. They cannot be final until
all that can be known is known, - until the end of all knowledge and of
time. It is because he feels so sure of what has been gained that the man
of science seems to the unscientific to claim finality for his results. He
himself is the first to point out that dogmatism is unjustified when its
assertions are not so thoroughly grounded in reasonable fact as to render
their contrary unthinkable. He seeks only for truth, realizing that new
discoveries must oblige him to amend his statement of the laws of nature
with every decade. But the great bulk of knowledge concerning life and
living forms is so sure that science asserts, with a decision often
mistaken for dogmatism, that evolution is a real natural process.

* * * * *

The conception of evolution in its turn now demands a definite
description. How are we to regard the material things of the earth? Are
they permanent and unchanged since the beginning of time, unchanging and
unchangeable at the present? We do not need Herbert Spencer's elaborate
demonstration that this is unthinkable, for we all know from daily
experience that things do change and that nothing is immutable. Did things
have a finite beginning, and have they been "made" by some _supernatural_
force or forces, personified or impersonal, different from those agencies
which we may see in operation at the present time? So says the doctrine of
special creation. Finally, we may ask if things have changed as they now
change under the influence of what we call the natural laws of the
present, and which if they operated in the past would bring the world and
all that is therein to be just what we find now. This is the teaching of
the doctrine of evolution. It is a simple brief statement of natural
order. And because it has followed the method of common sense, science
asserts that changes have taken place, that they are now taking place, and
furthermore that it is unnecessary to appeal to other than everyday
processes for an explanation of the present order of things.

Wherever we look we see evidence of nature's change; every rain that falls
washes the earth from the hills and mountains into the valleys and into
the streams to be transported somewhere else; every wind that blows
produces its small or greater effect upon the face of the earth; the
beating of the ocean's waves upon the shore, the sweep of the great
tides, - these, too, have their transforming power. The geologists tell us
that such natural forces have remodeled and recast the various areas of
the earth and that they account for the present structure of its surface.
These men of science and the astronomers and the physicists tell us that
in some early age the world was not a solid globe, with continents and
oceans on its surface, as now; that it was so very hot as to be semi-fluid
or semi-solid in consistency. They tell us that before this time it was
still more fluid, and even a mass of fiery vapors. The earth's molten bulk
was part of a mass which was still more vast, and which included portions
which have since condensed to form the other bodies of the solar
system, - Mars and Jupiter and Venus and the rest, - while the sun remains as
the still fiery central core of the former nebulous materials, which have
undergone a natural history of change to become the solar system. The
whole sweep of events included in this long history is called cosmic
evolution; it is the greater and more inclusive process comprising all the
transformations which can be observed now and which have occurred in the
past.

At a certain time in the earth's history, after the hard outer crust had
been formed, it became possible for living materials to arise and for
simple primitive creatures to exist. Thus began the process of organic
evolution - _the natural history of living things_ - with which we are
concerned in this and later addresses. Organic evolution is thus a part of
the greater cosmic process. As such it does not deal with the origin of
life, but it begins with life, and concerns itself with the evolution of
living things. And while the investigator is inevitably brought to
consider the fundamental question as to the way the first life began, as a
student of organic forms he takes life for granted and studies only the
relationships and characteristics of animals and plants, and their
origins.

But even as a preliminary definition, the statement that organic evolution
means _natural change_ does not satisfy us. We need a fuller statement of
what it is and what it involves, and I think that it would be best to
begin, not with the human being in which we are so directly interested,
nor even with one of the lower creatures, but with something, as an
analogy, which will make it possible for us to understand immediately what
is meant by the evolution of a man, or of a horse, or of an oak tree. The
first steam locomotive that we know about, like that of Stephenson, was a
crude mechanism with a primitive boiler and steam-chest and drive-wheels,
and as a whole it had but a low degree of efficiency measured by our
modern standard; but as time went on inventive genius changed one little
part after another until greater and greater efficiency was obtained, and
at the present time we find many varied products of locomotive evolution.
The great freight locomotive of the transcontinental lines, the swift
engine of the express trains, the little coughing switch engine of the
railroad yards, and the now extinct type that used to run so recently on
the elevated railroads, are all in a true sense the descendants of a
common ancestor, namely the locomotive of Stephenson. Each one has evolved
by transformations of its various parts, and in its evolution it has
become adapted or fitted to peculiar circumstances. We do not expect the
freight locomotive with its eight or ten powerful drive-wheels to carry
the light loads of suburban traffic, nor do we expect to see a little
switch engine attempt to draw "the Twentieth Century Limited" to Chicago.
In the evolution, then, of modern locomotives, differences have come
about, even though the common ancestor is one single type; and these
differences have an adaptive value to certain specific conditions. A
second illustration will be useful. Fulton's steamboat of just a century
ago was in a certain true sense the ancestor of the "Lusitania," with its
deep keel and screw propellers, of the side-wheel steamship for river and


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