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OSMANIA UNIVERSITY LIBRARYCaIINo.U9.9/C75D Accession No. 8 94Author Conklin E.G.,Tide Direction of human evolutionThk book should be returned on or before the date last marked below.


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THE DIRECTIONOF HUMAN EVOLUTION


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THE DIRECTION OFHUMAN EVOLUTION

BYEDWIN GRANT CONKJJNPROFESSOR OF BIOLOGY IN PRINCETolTuNIVERSITYAUTHOR OF "HEREDITY AND ENVIRONMENT IN DEVELOPMENT OF MEN," ETC.

HUMPHREY MILFORDOXFORD UNIVERSITY PRESS

LONDON EDINBURGH GLASGOWTORONTO MELBOURNE CAPETOWN BOMBAY


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Copyright, 1991, by Charles Scrtbner's Sonsfor the United States of America

Printed by The Scrlbner PressNew York, U. S. A.


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PREFACETHE lectures which constitute this volume were

given at the University of North Carolina in May,1920, under the terms of the "John Calvin McNairLectureship on the mutual bearings of science andreligion upon each other." One or two of themwere also delivered at Northwestern University,Mt. Holyoke College, Western University, and theUniversity of Texas.The topic chosen for this series is one in whichthe bearings of science upon religion are most vital,namely, the origin and destiny of the human race.I shall attempt to present certain conclusions ofscience regarding the evolution of man, and shallventure to draw from these conclusions certain in-ferences with regard to the future of the humanrace, but I have no desire to force others to acceptthese conclusions or inferences.The spirit of science is freedom to seek and to

find truth, freedom to hold and to teach any viewfor which there is rational evidence, recognitionthat natural knowledge is incomplete and subjectto revision, and that there is no legitimate com-pulsion in science except the compulsion of evidence.The method of science is to proceed from observa-


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vi PREFACEtions to tentative explanations which are thentested by further observations and experiments,thus reaching general explanations or theories.Scientific theories are not mere guesses but arebased upon careful, detailed observations, butwhere time and space forbid entering into details,as is true in these lectures, only general conclusionscan be given. On the other hand the philosophicaland religious deductions which are based upon sci-entific theories must necessarily be still more ten-tative, and it is hoped that the reader will take thisfor granted even though it is not always expresslystated.The aim of real science, as well as of true religion,

is to know the truth, confident that even unwel-come truth is better than cherished error, that thewelfare of the human race depends upon the exten-sion and diffusion of knowledge among men, andthat truth alone can make us free.

It is not my intention to argue the truth of thegeneral theory of organic evolution; the day forthis is passed. Evolution in the widest sense isaccepted by most men of science, and the evidencesfor it need not be recalled here. Nor do I proposeto present in detail the evidences for the evolutionof man; this has been done in many other placesand need not be repeated here. My purpose israther to consider the course of past evolution onlyin so far as it bears upon the present and to apply


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PREFACE viithe principles which have guided evolution in thepast to the present and future evolution of thehuman race. In doing this I hope not only to dealwith a phase of the subject which will be moreimmediately practical and profitable than a mereconsideration of past evolution would be, but whichalso may avoid many controversies, for whateverour views may be as to the past evolution of manthere is general belief in the present and future de-velopment and evolution of the human race.

Finally, in considering the bearings of evolutionupon government and religion, I realize that I amdealing with subjects which are generally regardedas quite outside the field of biology. However, Iam convinced that nothing which concerns man iswholly foreign to the fundamental principles oflife and evolution, and that the future progress ofmankind depends upon a rational application ofthe principles of science to all human affairs.Everywhere intellectual classes are breaking awayfrom old traditions; everywhere old faiths are be-ing critically examined; everywhere evidence is de-manded in place of authority, and the times callfor a restatement of the reasons for the faith thatis in us.The recent cataclysm which has swept over the

world, the perils of civilization, the threatenings ofrevolution and Bolshevism and the wide-spread re-crudescence of emotionalism, irrationalism, and


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viii PREFACEselfishness have caused all thoughtful people to lookanxiously to the future. Many persons believethat our civilization, like other civilizations of thepast, is showing signs of degeneration and decay,that throughout the world the less intelligent andmore selfish elements of society are coming to con-trol government, industry, and education, whilethe best elements are dying out or are losing con-trol. Others look forward with alarm to increasingconflicts between the races of mankind, to a " RisingTide of Color in the Struggle for World Suprem-acy,"* and to elimination of the finest types in"The Passing of the Great Race." f

Chesterton says that the World War put a stopto all our talk about human evolution, but this iscertainly not true. Never before have the prob-lems of the future evolution of man, whether pro-gressive or retrogressive, been so insistent and ab-sorbing, and never before has it been so importantfor men to get a comprehensive and steady view ofhuman evolution and of human destiny.

Certain portions or abstracts of these lectureshave been printed in Princeton University Lectures,Scribner's Magazine, the Yale Review, and theMethodist Church Congress Series. I am indebtedto these publications for permission to rewrite anftenlarge these portions for this volume. I wish also

*Stoddard, Lothrop, New York, 1920.t Grant, Madison, New York, 1918.


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PREFACE ixto express my obligations to Dr. J. H. McGregorof Columbia University for the photograph of hisrestorations of primitive men, which is reproduced inthe frontispiece, and to some of my colleagues forfriendly advice and criticism.

E. G. C.


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CONTENTSI. PATHS AND POSSIBILITIES OF HUMANEVOLUTION

PAGEI. INTRODUCTION 3

A. THE LAW OF CONTINUITY 7B. THE PRINCIPLES OF EVOLUTION ... 9

1. EVOLUTION IS TRANS-FORMATION ANDNOT NEW-FORMATION 92. EVOLUTION IS TRANSFORMATION OFGERMPLASM AND NOT OF DEVELOPED

BODIES OF ANIMALS OR PLANTS . . IO3. INFLUENCE OF ENVIRONMENT ON EVO-LUTION II

INHERITANCE OF ACQUIRED CHAR-ACTERS 134. SOCIAL INHERITANCE 14

C. THE RESULTS OF EVOLUTION .... 151. DIVERSITY 152. ADAPTATION l63. PROGRESS l6

(a) THE PATHS OF PROGRESS .... l8(6) PROGRESS MOST RAPID AT FIRST . 19

II. THE PAST EVOLUTION OF MAN 25III. MODERN RACES OF MEN 31IV. THE PEOPLING OF THE EARTH 36V. HYBRIDIZATION OF RACES 47

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xii CONTENTSPAOt

VI. PRESENT AND FUTURE EVOLUTION OF MAN . 54A. PHYSICAL EVOLUTION 54EUGENICS 56B. INTELLECTUAL EVOLUTION 65C. SOCIAL EVOLUTION 69D. MAN'S CONQUEST OF NATURE .... 77

VII. WILL THERE BE A HIGHER ANIMAL THAN MAN ? 79II. EVOLUTION AND DEMOCRACY

I. THE BIOLOGICAL FOUNDATIONS OF SOCIETY . 85A. PHYSICAL, INTELLECTUAL, SOCIAL EVOLU-

TION NOT ANTAGONISTIC 85B. SOCIAL PROGRESS MEANS GREATER SPE-

CIALIZATION AND CO-OPERATION . . 88C. SOCIETY FOUNDED ON INSTINCTS ... ,90

II. PROGRESS IN HUMAN HISTORY 95III. THE BIOLOGICAL BASES OF DEMOCRACY . . 100IV. PERSONAL LIBERTY vs. SOCIAL ORGANIZATION 112V. DEMOCRATIC EQUALITY vs. HEREDITARY IN-

EQUALITY 127VI. UNIVERSAL FRATERNITY vs. NATIONAL AND

CLASS ANTAGONISMS 134CONCLUSION 155

III. EVOLUTION AND RELIGIONI. THE NATURE OF RELIGION 161

A. COSMIC MYSTERIES 162


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CONTENTS xiiiPAGE

B. THE PROBLEM OF EVIL 163C. THE INNER CONFLICT 165D. THE FUNCTION OF RELIGION . . . . 166

II. THE EVOLUTION OF RELIGION 169III. THE CONFLICT BETWEEN THEOLOGY AND SCI-

ENCE 178IV. NATURE AND THE SUPERNATURAL .... 185

A. POPULAR MISCONCEPTIONS OF NATUREAND THE SUPERNATURAL . 186B. SCIENTIFIC CONCEPTION OF LAW ... 193C. SUPERNATURALISM IN RELIGION ... 197

V. EVOLUTION vs. CREATION 202VI. EVOLUTION AND THE BIBLICAL ACCOUNT . . 206VII. Is EVOLUTION ATHEISTIC? 209VIII. EVOLUTION AND THE DOCERINE OF DESIGN . 218IX. THE NATURE OF MAN 230X. THE RELIGION OF EVOLUTION 237

A. PROGRESS THROUGH STRUGGLE .... 237B. ETHNOCENTRIC RATHER THAN EGOCENTRIC 240C. THE OUTCOME OF EVOLUTION .... 245


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PATHS AND POSSIBILITIES OFHUMAN EVOLUTION


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INTRODUCTIONUNTIL about fifty years ago it was generally be-

lieved, even by scientists, that man had been re-cently and miiaculously created, and that he stoodapart from the rest of nature in solitary grandeur.It was thought that the whole past history of manand even of the earth and stellar universe had beena very brief one, dating back only to about 4,000years B. C., or approximately 200 human genera-tions, and many persons confidently expected thatthe future would be even shorter. It is an inter-esting fact that until very recent times the insta-bility of nature and its approaching end weredeeply impressed on most minds. Prophets lookedforward to a speedy end of the world; poems werewritten on "The Last Man"; various sects pre-pared their ascension robes and waited for thecomet to strike the earth or the eternal trumpet tosound; and even those who did not prepare oftenbelieved and trembled.What a revolution has occurred in our concep-tion of man and nature during the past few years !Science has taught us something of the wonderfulstability of nature, something of the continuityand eternity of natural processes, something of the

3


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4 PATHS AND POSSIBILITIESuniversality of natural law, something of the im-mensity of time and space. There is no longerany doubt among scientists that man is descendedfrom animal ancestors. There is no longer anyserious question among leading biologists and an-thropologists that not only the body, but also themind and society of man are the products of evo-lution. For a time there was a tendency to admitthe truth of evolution so far as man's body wasconcerned, but to deny it in respect to his mindand society. But this position was satisfactoryto no one. Neither the evolutionist nor the specialcreationist could be satisfied with such a dividedorigin for man, and more recent work on the psy-chology and society of different races of men andof animals below man has shown the same sort ofevidence for the evolution of human intellect andsociety as for the evolution of the body. Man, then,in his entirety is regarded by science as the productof evolution. His actual origin goes back not toAdam and Eve and the Garden of Eden, 6,000years ago, but to more primitive races of men, andthen to prehuman ancestors, and in the end tothe earliest forms of life upon the earth. Betweenus and these earliest forms there has been an un-broken line of descent, an uninterrupted streamof life through all the ages.And this enormously long past history leads usto believe that the future will be equally long. It


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PATHS AND POSSIBILITIES 5has been customary to look upon evolution as aprocess which flourished mightily "in the darkbackward and abysm of time" but which has prac-tically come to an end to-day. But evolution looksforward as well as backward. The eternal laws ofnature will not cease to operate to-day or to-morrow.We are creatures of a day; our lives are mere pointsin the great curve of evolution; what changes thefuture may have in store for the human race no mancan clearly foresee. And yet one who stands onthe shore and sees the curve of the sky and sea can,in imagination, extend this arc until it circles theglobe, and he feels the earth beneath him rollingthrough space. From a few observations an astron-omer can calculate the whole orbit of a comet andpredict when it will return, perhaps hundreds orthousands of years hence. And so, although wecatch but glimpses of great processes which comeout of eternity and go into eternity, we can projectthe great principles of past evolution into the futureand venture upon a scientific prophecy of "Whatmankind shall be."

It was the peculiar ability of Darwin to seenature in four dimensions length, breadth, depth,and duration. He observed the activities of earth-worms for a season, and then calculated the agri-cultural and geological importance of worms actingthrough many years. He observed the minor varia-tions of animals and plants, and then saw the evo-


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6 PATHS AND POSSIBILITIESlutionary significance of such changes when ex-tended throughout geological time. He saw thegreat destruction of weak and ill-adapted plantsand animals each year, and projecting this processbackward through the ages found a natural ex-planation for the wonderful fitness of organisms.One who stands on the brink of the Grand Canon

and reflects on the duration of time necessary fora stream of water to have cut this vast chasm inthe solid rock, and then thinks of the still longertime during which these rocks were being laid downas sediments beneath the sea, has a measuring-rodwhich may be used in estimating the duration ofthe evolutionary process. One who views man,not as the creation of a few years ago, but as theproduct of vast series of prehistoric ages such aone only can take the long view with regard to thehuman race, not only as to the past but also asto the future.There is increased breadth of view and accuracy

of judgment and increased confidence and satis-faction in the long view of the human race as con-trasted with the short view. One who has in mindthe whole course of evolution and of human his-tory will not be deceived into thinking that localeddies and back currents are the main stream.One who recalls what the human race has come upfrom will not yield to despair over the presentcrises of civilization. Even the selfishness, stu-


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PATHS AND POSSIBILITIES 7pidity, and irrationality of men will not cause himto forget the advances of the past nor to lose faithin the future. The long view of human historyis not only the sane and rational one, but it is alsothe hopeful view.

It is often said that science deals only with thepast and present and leaves the future to prophetsand seers. This is true with regard to many de-tails the causes of which are numerous and com-plex. But on the other hand it is possible to pre-dict general tendencies and phenomena which willresult from fundamental principles and causes.The details of the future evolution of man no onecan predict, but the outcome of the general prin-ciples of evolution may be predicted, for we haveconfidence that these principles are constant andthat they will continue to operate in the future asin the past. What are these principles?

A. THE LAW OF CONTINUITY"Pour juger de ce qui est arrive, et m&me de ce qui

arrivera, nous n'avons qu'i examiner ce qui arrive" (Buf-fon, "Theorie de la Terre.")"To understand what has happened, and even

what will happen, we have only to examine what ishappening." This is what has been called the"Law of Continuity " or more accurately the"Doctrine of Uniformity," namely, the belief thatnature is uniform and her processes continuous, that


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8 PATHS AND POSSIBILITIESthe laws of cause and effect, of gravity, of conser-vation of matter and energy, of thermodynamics,chemical affinity, life and death, heredity, develop-ment, and evolution are the same yesterday, to-day,and forever. The astronomer, physicist, and chem-ist believe that laws of gravity, light, electricity,and the combinations and dissociations of chemicalelements are the same to-day as when the "morn-ing stars first sang together." The biologist be-lieves that the animals which lived and reproducedon the shores of the Paleozoic seas had protoplasmand cells, nuclei and chromosomes, and that theirnutrition, reproduction, embryonic development,senescence, and death were essentially the same asin the animals we now study at our marine labora-tories; that the Mendelian laws of inheritance, varia-tion, and evolution applied to the earliest livingthings as well as to the latest. All science is basedupon the fundamental belief that in natural laws"there is neither variableness nor shadow of turn-ing." Variableness in events (not in laws), andeven what we call chance, are not capricious butare themselves governed by law; they are merelythe results of new combinations of existing factorsor causes. We have applied this principle of con-tinuity and uniformity to the past evolution of theuniverse, to the stars, solar system, and earth, tothe evolution of animals and plants, and even ofman; and in the light of what is happening now


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PATHS AND POSSIBILITIES 9have been able to judge what has happened in thepast. And where the factors involved are not toonumerous we can apply this principle to the futureand determine what will happen in time to come;and, even where it is not possible to predict withcertainty particular events because of the com-plexity of the factors involved, it is yet possibleto determine future tendencies and oossibilities.

B. THE PRINCIPLES OF EVOLUTIONi. Evolution Is Trans-formation and Not New-

formationEvolution consists in new combinations of the

elements of which organisms are composed and notin the formation de now of such elements. Nowherein nature, neither in the living nor in the lifelessworld, is there such a thing as creation out ofnothing. Every new thing is formed by new com-binations of things already present. In chemistryand physics these are the atoms or the electrons ofwhich the atoms are composed; in biology they arethe organs, cells, chromosomes, the hereditary char-acters, inheritance units, or the molecules of whichsuch units are composed. Evolution does not con-sist in the creation de novo of molecules, units, char-acters, organs, or functions, but rather in new com-binations of these.At the same time it must be recognized that new

combinations give rise to new qualities. When


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io PATHS AND POSSIBILITIEShydrogen and oxygen combine they produce some-thing which is different from either, and when differ-ent hereditary units combine they produce char-acters unlike those of the parents; even in the forma-tion of new hereditary units, or what are now calledmutations, we have only new combinations of theelements of which such units are composed. Thisformation of new qualities as the result of newcombinations of the same old elements may becalled, following Bergson, " creative evolution,"but it is important to remember that it does notdiffer essentially from the similar phenomenon inchemistry and physics which is known as "creativesynthesis," and that it results merely from new com-binations, that it is transformation and not new-formation.

2. Evolution Is Transformation of Germplasm andNot of Developed Bodies of Animals or PlantsThe only living bond between successive genera-

tions is found in the germ cells, which extend backfrom us without a break to our earliest progenitors,and any evolutionary changes which are to trans-form races or species must take place in thesegerm cells. The body may undergo great changesas the result of environment, use or disuse, or othercauses, but the body is mortal it develops anddies in each generation whereas the germ cellsare, potentially at least, immortal. Consequently


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PATHS AND POSSIBILITIES nchanges in heredity are due to changes in theimmortal germplasm rather than in mortal bodies;and evolution, which is based on changes in hered-ity, consists in the evolution of germplasm ratherthan of developed organisms.In spite of much controversy, due largely to lack

of clear thinking, it is now practically certain thatcharacters acquired by the mortal body are notinherited; that is, are not transmitted to the germ-plasm. Evolutionary changes are not first wroughtin developed bodies but in germplasm.

3. Influence of Environment on EvolutionAll theories as to the causes of evolution agree

in ascribing more or less importance to the influ-ence of environment. Lamarckism maintains thatchanges in individuals are caused directly bychanges in environment, and that these individualchanges are inherited and thus bring about racialchanges. Darwinism teaches that " variations ofevery sort are caused by changed conditions oflife/' but that those which are injurious are quicklyeliminated while only those which are beneficial,that is, well adapted to environment, persist andconstitute the building materials of evolution.The mutation theory of de Vries teaches that varia-tions are of two distinct kinds: first, fluctuationswhich are changes in the developed organism andare not inherited; and second, mutations which are


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12 PATHS AND POSSIBILITIESchanges in the germplasm and are inherited.Fluctuations are caused chiefly if not entirely bychanges in environment, and while the causes ofmutations are not known with certainty it seemsmost probable that they also are to be foundin environmental influences meaning by environ-ment everything which surrounds the inheritanceunits or genes of the germplasm. These mutationsappear without reference to whether they are valu-able or injurious; as a matter of fact probably onlyone out of a thousand is beneficial, but those whichare injurious are eliminated by the environment.Consequently the direction of evolution has to acertain extent been determined by the environ-mental conditions.In short, all modern theories of the causes of

evolution maintain that heritable variations areprobably caused by changes in environment, andall evolutionists to-day believe that whether thesevariations survive or are wiped out depends upontheir relation to environment. Environment thusplays a very important part in evolution, and anyhypothesis that wholly discards or disregards thisfactor can have no standing in science.But, on the other hand, this does not justify the

opinion that environmental changes are the solecauses of evolution. Undoubtedly the organismthat is acted upon is as important as the environ-ment which acts upon it. Evolution is one of the


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PATHS AND POSSIBILITIES 13responses of the germplasm to environmental stim-uli, and the character of the response is deter-mined in large part by the constitution of the germ-plasm rather than by the stimulus. Thus both theorganism and its surroundings, its hereditary con-stitution and its environment, are concerned inevolution, as well as in development or any othervital activity. It is certain that the outer environ-ment may act directly upon germ cells, or indirectlythrough the inner environment of the body. Butthis does not mean that germ cells react to environ-ment in identically the same way that body cellsdo; indeed every kind of cell responds to environ-mental stimuli in its own peculiar way musclecells in one way, nerve cells in another, gland cellsin still another, and it is probable that differentkinds of germ cells, or even the same kinds at dif-ferent stages in their development, respond to thesame environment in different ways.

Inheritance of Acquired Characters. But, assum-ing that the hereditary constitution of the germcells may sometimes be changed by environmentalinfluences, there is no argument in this for the " in-heritance of acquired characters/' For both ver-bally and historically this expression means thatchanges in body cells produced by environmentalinfluences are transmitted through the germ cellsto the body cells of the next generation; and ana-lyzing this process further it would imply that par-


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14 PATHS AND POSSIBILITIEStides or units of the germplasm must react toenvironmental changes in exactly the same way asorgans or parts of the body do. In short, "in-heritance of acquired characters " implies that thegerm is the body in miniature, and this is certainlynot true.

Furthermore, it is known as a matter of factthat acquired characters are not usually, if ever,inherited. Environment, training, education maygreatly modify the glands, muscles, and nerves,but they do not change the germplasm so as toproduce these identical modifications in the nextgeneration. The hope of permanently improvingthe human race, or any other species, in this man-ner can only lead to disappointment and failure.

4. Social InheritanceAt the same time it must be remembered that

man transmits to his descendants not only a par-ticular germplasm, consisting of hereditary units,which determine his bodily qualities and mentalcapacities, but he also hands down through lan-guage, education, and customs, and not throughthe germplasm, his own personal acquirements,experiences, and possessions. This may be called" Social Inheritance," though it is a totally differentthing from "Biological or Germinal Inheritance."In this sense we have inherited from our parentslanguage, property, customs, laws, institutions.


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PATHS AND POSSIBILITIES 15They are no part of our germplasm, nor even of ourbone and sinew and brain, but rather of our envi-ronment. Because of this social inheritance societymay advance from age to age, each succeeding gen-eration starting where the preceding one ended, asin a relay race whereas in our germinal inheri-tance each generation begins where the previousone began, namely from an egg-cell, and the wholecourse of development must be repeated in eachgeneration.

C. THE RESULTS OF EVOLUTIONIn the course of evolution organisms have moved

forward, backward, and sidewise, or rather theyhave spread as the branches of a tree, some ofthem merely diverging at the same level of organi-zation, others growing upward, and still othersdownward. The results of evolution may be sum-marized in three words: Diversity, Adaptation,Progress.

i. DiversityDiversity is seen in the innumerable variations,

mutations, and species of the living world. Mostof these are no more complex or perfect than thestocks from which they have sprung, and some ofthem are degenerate descendants of more perfectancestors. Diversity, in short, is mere change,whether progressive or retrogressive, whether use-ful, indifferent, or harmful.


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1 6 PATHS AND POSSIBILITIES2. Adaptation

Adaptive evolution is increasing perfection of ad-justment to conditions of life. The only scientificexplanation of such adjustment or fitness is Dar-win's principle of natural selection of the fit andelimination of the unfit, and it is eloquent testimonyto the greatness of Darwin that more and more thisgreat principle is being recognized as the onlymechanistic explanation of adaptation. Whethernatural selection is a complete explanation of alladaptation may be doubted, but at least it is oneof the most important causes of adaptive evolution.

3. ProgressProgressive evolution is the advance in organiza-

tion from the simplest to the most complex or-ganisms, from amoeba to man. Biological progressmeans increasing complexity of structures and func-tions, increasing specialization and co-operation ofthe parts and activities of organisms, and humanprogress, whether physical, intellectual, or social,means no more and no less than this.

It is often assumed that there are no necessarylimits to progress in any line, and that the pastcourse of evolution shows that man came fromprimordial protoplasm and will go on to endlessgrowth and glory. But as a matter of fact the pastcourse of evolution teaches that the limits of prog-ress are fixed by its very nature. No single animal


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PATHS AND POSSIBILITIES 17or plant, however complex it may be, can combinewithin itself all the complexities of all organisms.Increasing specialization means increasing limita-tions in certain directions in order to advance inothers. If a creature have wings it cannot alsohave hands (except in art where angels are givenan extra pair of appendages and hair and feathersare mixed regardless of zoological classification) ; ifits limbs are differentiated for running they cannotalso be specialized for swimming; if it have enor-mous strength it cannot also have great delicacyof movement. Thus while certain animals arespecialized in one direction, and others in another,no animal can be differentiated in all directions.

Furthermore, increasing specialization leads tolack of adaptability; peculiar fitness for any specialcondition of life means unfitness for other and differ-ent conditions. When differentiations in any onedirection go so far that they unfit the organism forany condition of life except a single and specialone, the chances for survival are greatly reduced,and sooner or later this highly differentiated or-ganism becomes extinct or returns to a more gen-eralized type.

Paleontology is, in the main, the science of or-ganisms that were too highly differentiated to ad-just themselves to the new conditions that cameupon them and which therefore became extinct.The death of species, like the death of individuals,


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i8 PATHS AND POSSIBILITIESis the price that is paid for differentiation. One-celled organisms and all germ cells are potentiallyimmortal, but the highly differentiated bodies ofanimals and plants and their highly differentiatedmuscle, nerve, and tissue cells are mortal, probablybecause they are too highly specialized to adjustthemselves to all the changing conditions of exist-ence.

Similarly species that are not highly specializedare highly adaptable, and have great powers ofsurvival, while those that are highly specializedhave little adaptability, and consequently are morelikely to become extinct. For this reason newpaths of evolution usually start from generalizedrather than from highly specialized types.

(a). The Paths of Progress. Millions of diver-sities exist among organisms, and they are appear-ing continually; thousands of adaptations havearisen during the course of evolution and are stillarising; but different lines of progress have beenrelatively few. The most important paths of prog-ress throughout all the past ages have been in thedirection of

(1) Increasing bodily complexity, or the multipli-cation and differentiation of cells, tissues, organs,and systems;

(2) Increasing intelligence, or the capacity ofprofiting by experience, which comes with increas-ing organization of the nervous system;


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PATHS AND POSSIBILITIES 19(3) Increasing social organization, or the differ-

entiation and integrations of individuals or persons,whether among ants, bees, or men.(6). Progress Most Rapid at First. In all these

paths of evolution progress is most rapid at first,and it then slows down until it stops. It may becompared to a curve which rises rapidly at first,and then approaches more and more to a straightline. Or better still, it may be compared to aflow of lava which rushes forward while it is atwhite heat and fresh out of the crater, but goesmore and more slowly as it cools until it stops al-together; if the central stream remains fluid (orthe organism remains labile and relatively undiffer-entiated) it may burst out and again flow rapidlyin one direction or another until it again cools andstops.The rate of evolution has not been uniform

throughout the past. Apparently there have beenperiodic advances or waves of evolution. De Vriesthinks that there have been periods of mutationalternating with periods of stability in the historyof species. Paleontologists have generally attrib-uted these evolutionary waves to changes in envi-ronment, and they call attention to the evidencethat the periods of most rapid human evolutioncoincided with the great climatic changes duringthe four successive glacial epochs and the inter-glacial periods.


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20 PATHS AND POSSIBILITIES(i) Bodily Complexity. Probably the furthest

possible limits of progressive evolution have alreadybeen reached in all well-tried lines of progress.Further progress must be made in new lines if atall, and from generalized rather than from highlyspecialized types.

One-celled organisms reached their utmost limitsof complexity millions of years ago; since then theyhave shown many diversities, many adaptations,but little if any progress.

Also many-celled animals and plants long agoreached the limits of their possible progress inalmost every line. Multiplication of cells, tissues,organs, systems, metameres, and zooids enormouslyincreased the possibilities of specialization withineach of these larger units of organization, but formillions of years there has been little further prog-ress in this direction of multiplicity and com-plexity. Only about fourteen times in the wholehistory of life upon the earth have new animalphyla appeared, and many of these were mereblind alleys which led nowhere, not even tomany species; there have been no new phyla sincefishes appeared in the Silurian age, no new classessince mammals appeared in the Triassic and birdsin the Jurassic. Each of these classes of Verte-brates reached its maximum of complexity in theages immediately following its first appearance,and thereafter it maintained only this level or more


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PATHS AND POSSIBILITIES 21frequently underwent a decline. The amphibianswhich first appeared in the Carboniferous reachedtheir greatest complexity in the Permian. Thereptiles which first appeared in the Permian reachedtheir climax in the Mesozoic. The mammals whichappeared in the Triassic reached their greatest de-velopment in the Quaternary.What is true of great classes of organisms such

as those named is equally true of families, genera,and species. One need only recall the paleon-tological history of dinosaurs, elephants, camels,etc., to realize that, measured by geological time,organisms rather quickly reach the limits of theirprogress in any particular line. Diversities maycontinue to appear in all these types. Many newspecies have evolved and are still appearing, therehave been diversifications and adaptation almostwithout limit, but progress in the sense of increas-ing complexity of organization has practically cometo an end.

(2) Animal Societies. There are many gradesof individuality in the living world from the visibleand even the invisible parts of cells to whole cells,cell aggregates, tissues, organs, systems, persons,compound animals, and finally colonies and states.There are many grades of organization from thebacterium to the vertebrate, from the germ cell tothe man. Animal societies are the highest gradeof organization which has yet appeared on earth.


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22 PATHS AND POSSIBILITIESIn such societies the specialization and co-operationof persons make possible a higher degree of organ-ization than has ever appeared before.The evolution of animal societies may be traced

from a condition in which every individual is muchlike every other one, and the bond of connectionbetween them is very slight, up to societies of ants,bees, and termites, in which the specialization andco-operation of individuals is extraordinarily de-veloped.Already differentiation among ants and termites

has gone so far that in the most complex coloniesthe three principal functions of life, namely nutri-tion, reproduction, and defense, are no longer foundin the same individuals; "workers" are unable toreproduce or to defend the colony, males and fe-males are unable to get food or to defend themselves," soldiers" are unable to reproduce or even to feedthemselves. At the same time co-operation withinthe colony is practically perfect. It is difficult toimagine how differentiation and integration cango farther than this, and unless it does go fartherprogress in this direction has come to an end.

(3) Intellectual evolution is the last, and, fromthe human point of view, the most important pathof progress which has ever been discovered by or-ganisms. In lower animals intellect is either lack-ing or is but little developed, and behavior is guidedentirely by rigid instincts; in higher animals it is


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PATHS AND POSSIBILITIES 23more fully developed, but instinct is still the ruleof life; in man only has intellect become to a cer-tain extent the master of instinct, so that he can-not only regulate his conduct in the light of experi-ence but can to a certain extent forecast the futureand prepare for it.

Here, as in the case of physical and social evolu-tion, the factors or elements out of which the newproduct, intellect, is built are present in the lowestand simplest forms of life, but it is only by the in-creasing differentiation and integration of theseelements that progress is achieved. The elementsout of which the psychic faculties of man have beendeveloped are present in all organisms, even ingerm cells, in the form of sensitivity, tropisms, re-flexes, organic memory, "trial and error/' and afew other properties; in more complex animalsthese take the form of special senses, instincts,emotions, associative memory; in the highest ani-mals, and especially in man, they blossom forthas intelligence, reason, will, and consciousness.Many stages of this development may be seen invarious animals below man, and also in the devel-opment of the human personality from the germcells.*There is no evidence that intellectual progress,

as distinguished from mere diversity, is still goingon among animals, and that they will ultimately*See Conklin, "Heredity and Environment/- 1920, pp. 32-56.


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24 PATHS AND POSSIBILITIESgraduate into man's class. For thousands of yearsman has endeavored to improve by selective breed-ing the intelligence of certain animals, especiallyof dogs and horses; undoubtedly much improvfr-ment has been made, but in intelligence, as in otherqualities, a limit to improvement is sooner or laterreached beyond which it is not possible to go.

In bodily complexity, social organization, andintellectual capacity progressive evolution has vir-tually come to an end among organisms below man;further progress, if it occurs, must be in new pathsand from generalized rather than from highly spe-cialized types. Has progressive evolution come toan end in the case of man also?


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II

THE PAST EVOLUTION OF MANSOLAR years, individual lives, and human genera-

tions are too brief to be used as an adequate measur-ing-rod for the enormously long process of humanevolution. We generally count time from thebirth of Christ, and to us this seems a remote event.But the birth of Christ is no more than midwaybetween our times and the earliest civilization inEurope,* while the civilizations of Egypt and Meso-potamia go back to a period at least 3,000 yearsB. C. At this remote time there were in the val-leys of the Nile, Euphrates, and Tigris great citiesand states, highly organized forms of society, anda culture represented by some of the greatest monu-ments of human history, highly developed agricul-ture and industries, the use of metals and the re-cording of laws, customs, wars, and even of scien-tific observations in writings. Even one thousandyears earlier, at the date fixed upon by ArchbishopUsher for the creation of the world and of man, viz.,4000 B.C., there were in these valleys great popula-tions that had domesticated horses, donkeys, cattle,sheep, goats, ducks, and geese; that were cultivatingbarley, millet, wheat, and flax; that had through

* Crete.25


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26 PATHS AND POSSIBILITIESlong periods of time developed various improvedbreeds and races of these animals and plants fromtheir originally wild stocks. They had begun thesmelting of ores and the use of copper implements;there were skilled craftsmen in various industries;they had a complicated system of writing and haddeveloped a calendar of twelve months of thirtydays each, with five feast days at the end of theyear, thus showing a remarkable knowledge of as-tronomical time. Adam and Eve may well havebeen civilized human beings, for, according to theUsher chronology, they came only in the fulness oftime and of human populations, and after the be-ginnings of civilization.But back of this civilization lay long years of

barbarism and savagery, known as the neolithicand the paleolithic ages. The records of the formerare found in various parts of the world in caves,cliffs, and lake-dwellings, in skeletons from ceme-teries, caves, and sedimentary deposits of lakes andrivers, accompanied by bricks and pottery, beautifulstone implements, ornaments of various kinds, andcarvings and paintings on walls and cliffs. Whileit is difficult to date this neolithic age, the best evi-dence indicates that around the Mediterranean itgoes b&ck to near the end of the last glacial epoch,say approximately 10,000 years ago.Back of this neolithic age lie the paleolithic ages

of savagery, the records of which are for the most


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PATHS AND POSSIBILITIES 27part stone implements and weapons; the latest ofthese are of beautiful workmanship, while theearliest are so crude that it is often difficult to de-cide whether or not they are the work of man.Along with these artifacts, skeletal remains havebeen found which indicate that the men of the laterpaleolithic ages were of the same species and hadthe chief physical characteristics of the presenthuman species, Homo sapiens, and the stratigraph-ical evidences indicate that in Europe the existingspecies of man goes back at least 20,000 to 30,000years.*In the still more remote past occur skeletal re-

mains of other and more primitive species of man.Most of these are represented by one or at most afew specimens, but one of the extinct species ofman, Homo neanderthalensis, is represented by atleast six skulls as well as other remains found invarious parts of western Europe from Gibraltarto Germany. This Neanderthal type was dis-tinctly more ape-like than the present species: hehad a low, retreating forehead, heavy supraorbitalridges, protruding jaws and face, and retreatingchin. Rude flint implements associated with theseremains indicate that the Neanderthal man wasable at least to chip flint so as to produce weaponsand implements with sharp cutting edges. These

* On this subject see especially Henry Fairfield Osborn's " Men ofthe Old Stone Age," New York, 1916.


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28 PATHS AND POSSIBILITIESremains are associated with the skeletons of othermammals, many of them now extinct, which charac-terize the later Pleistocene of Europe, and the pre-vailing opinion among geologists is that they be-long to the period of the third or fourth glacialepoch. It is obviously impossible to translate thesegeological epochs into years with any degree ofcertainty, but at a venture it may be said that theNeanderthal race lived somewhere between 25,000and 100,000 years ago. We do not know whetherthe Neanderthal species evolved into modern man,or whether he amalgamated with other types, orwhether he was exterminated by the existing species,but in western Europe he appeared before the pres-ent species and was finally completely replaced byit.

Other types of man of a still more ape-like~formare represented by a few skeletal remains in earliergeological formations. One of the most importantof these fossils is the famous Heidelberg jaw, foundin 1907 near Heidelberg, Germany. It is unlikeany other human jaw in its unusual massivenessand lack of a chin, and yet the teeth are distinctlyhuman in shape. There can be no reasonabledoubt that it represents a species of man still moreprimitive and ape-like than the Neanderthal type,and accordingly this species has been named Homoheidelbergensis. This jaw was found at a depth ofseventy-nine feet below the surface, associated with


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PATHS AND POSSIBILITIES 29remains of many extinct mammals qf the first orsecond interglacial period, and it therefore carriesthe human record back to the middle or earlyPleistocene, possibly 250,000 years ago.

Finally the earliest type of man-like creature sofar discovered is the erect ape-man, Pithecanthropuserectus, discovered by Dubois at Trinil, Java, in1892. These remains consist of a skull cap, a tooth,and a thigh-bone, and it is evident that they belongto a type intermediate between man and the higherapes that they are, in short, one of the long-sought " missing links." The geological formationin which these fossils were found includes manyextinct mammals of the late Pliocene or pre-glacialperiod, possibly 500,000 years ago.

It is by no means certain that Pithecanthropusand the Heidelberg and Neanderthal races standin the direct line of descent of modern man; for allwe know to the contrary they may be collateralbranches from the main human stem. But theydo represent the most primitive types of man sofar discovered.Even at this early stage, half a million years

ago, the human line was already distinct fromthose of the higher apes, although these lines werethen much closer together than at present, and theactual period at which they come together is as-sumed by Osborn to have been in the Oligoceneage, perhaps a million years earlier. If this opinion


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30 PATHS AND POSSIBILITIESis correct the line of man's descent has 'been dis-tinct from that of his nearest living relatives, theanthropoid apes, for an immensely long period oftime, perhaps one or two million years. The entireChristian Era represents not more than i-5oth partof the time since the Neanderthal man flourished,not more than i-25oth of the time since Pithecan-thropus, and probably not more than i-5ooth partof the time since the human line split off from thatof the apes. The human race is very old as mea-sured by our years and generations, and back of thefirst appearance of human types lie unnumberedmillions of years during which evolution was mov-ing on from the lowest forms of life to the highestfrom amoeba to man.


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Ill

MODERN RACES OF MANWHEN for a few centuries one group of humanbeings became isolated from others there devel-

oped, as happens now with most animals andplants, local varieties, mutants, and races, whichwere probably peculiarly adapted to the local con-ditions, owing to the struggle for existence and thesurvival of the fit. Thus, for example, if the colorof primitive man was reddish or brownish, white oryellow or black men may have arisen in differentregions, and at different times as mutants, or heredi-tary varieties. These mutations would have per-sisted if not positively injurious, and they wouldhave gradually replaced individuals of other colorsif they had been better adapted to local conditions.Once a few mutant races were established, diversi-fications of mankind proceeded not only by muta-tion and natural selection but also by the processof cross-breeding, and the very numerous subraces,types, and breeds of mankind owe their origin inconsiderable part to such mixtures of mutant races.The principles of Mendelian inheritance show

that for every pair of contrasting characters in thetwo parents, as for example straight or curly hair,


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32 PATHS AND POSSIBILITIESbrown or blue eyes, there are two types of grand-children showing these characters; when there arefive such pairs of contrasting characters in theparents there may be (2) 6 or 32 types of grand-children showing various combinations of these fivecharacters; when there are ten pairs of contrastingcharacters there may be (2)

10 or 1,024 types ofgrandchildren. Between different races there aremany more than ten unit differences, and thus witha relatively small number of mutant characters anenormous number of different combinations of thecharacters is possible in the offspring. Subsequentinbreeding of such a mixed race leads to the separa-tion or segregation of particular types, having cer-tain of these combinations, from other types havingother combinations. In this way, practically all ofour domestic animals and cultivated plants havebeen produced, and probably many, if not all, exist-ing branches of the human species owe their origin,not only to mutations, but also to the mingling ofsuccessive waves of migration and the amalgamationof different mutant types, which had arisen andmultiplied in isolated regions. Since the earlyradiations from the birthplace of the species therehave been many currents of migration running inmany directions which have led to a more or lessintimate commingling of different types, and wheresuch commingling was later followed by isolation,races or subraces were formed. In this manner,


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PATHS AND POSSIBILITIES 33probably all the numerous existing branches of thehuman species were established.Three primary races of mankind are generallyrecognized in the world to-day, namely the white,yellow, and black races the brown and red racesbeing generally regarded as offshoots of one ormore of these primary races. In addition to theseprimary races there are many subraces and breeds,most if not all of them being of hybrid origin. In-deed there are few if any types of mankind to-daythat are not, hybrids between races, subraces, orbreeds. Among these subraces are the light andthe dark whites, and several types of browns, reds,yellows, and blacks. In each of these groups thereare innumerable varieties that run into one anotherby insensible degrees, as would be expected in thecase of hybrids.The question has often been raised whether theprimary races of mankind do not represent distinct

species. It is difficult, if not impossible, to definethe term " species" in a manner which will be uni-versally acceptable, but in general biologists agreethat in the animal and plant world true speciesdiffer in more respects and to a greater degree thando the primary races of mankind. Furthermore,true species do not generally produce fertile hybridswhen interbred, though there are many exceptionsto this rule, whereas all races of mankind producefertile hybrids when crossed. Therefore systema-


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34 PATHS AND POSSIBILITIEStists generally agree that there is at present but onespecies of man, namely Homo sapiens, and that allraces and varieties have arisen in the first instancefrom a common human stock.Again the question is often asked: Which of these

races of mankind represents most nearly the orig-inal ancestral stock, and which has departed farthestfrom that stock. Comparison of any modern racewith the Neanderthal or Heidelberg types showsthat all have changed, but probably the negroidraces more closely resemble the original stock thanthe white or yellow races. The separation of theseprimary races occurred long before the historic era.In the period of the cave men of Europe, possibly25,000 years ago, remains of two races have beenfound, the Cro-Magnons, resembling more closelythe white or brown races of the present, and theGrimaldi race with negroid characteristics. We donot know when the white and yellow races firstbecame distinct, but this also was probably at avery remote period.The subraces and minor subdivisions of the hu-

man species have arisen much more recently, someof them within the historic era, and many, if notmost of them, as the results of migration and hy-bridization. Three branches of the white race inEurope are generally recognized, namely the tall,blond, Nordic race of northern Europe; the stocky,dark, Alpine race, probably of Asiatic origin; and


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PATHS AND POSSIBILITIES 35the small, dark, Mediterranean race surroundingthe sea of that name, and probably extending east-ward to India.*The subdivisions of the other primary races as

well as the many hybrid types found in variousparts of the world cannot be considered here. Butemphasis must be placed upon the fact that theevolution of these subraces was not due entirelyto divergent mutations of an originally commonstock, but also to recombination and hybridizationof groups already present, which probably arose inthe first instance as a result of mutation and diver-gent evolution.Furthermore it is probable that many charac-

teristics which have hitherto been regarded ashereditary or racial may be due to environmentalcauses; it is probable, for example, that stature,long-headedness (dolicocephaly) or round-headed-ness (brachycephaly), etc., may sometimes be causedby higher or lower activity of the thyroid glandand that this may be influenced by food, particu-larly by the iodine intake.

* For a full discussion of these races see Madison Grant's "ThePassing of the Great Race," New York, 1918.


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IVTHE PEOPLING OF THE EARTH

MAN has always been a wandering animal; heis the most wide-ranging of all mammals. Fromhis earliest home, probably in the table-lands ofcentral Asia, successive waves of human migrationhave flowed forth in all directions. The recordsof these earliest wanderings are lost in the haze ofimmense antiquity but we have reason to believethat for at least a thousand centuries primitiveman wandered over vast regions of Asia, Europe,and Africa. Long before the beginnings of recordedhistory men had found and occupied every habita-ble land on the globe with the possible exceptionof a few distant oceanic islands. Everywhere the"aborigines," who were found by white men intheir earliest explorations, were not the first inhabi-tants, but were invaders who had driven out stillearlier peoples. When the Maoris first came toNew Zealand, they found an earlier race there, theMorioris, whom they exterminated or drove outto more inhospitable lands such as the ChathamIslands; when the Australian "aborigines" firstcame to that land they found it already occupied

36


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PATHS AND POSSIBILITIES 37by another race who retreated before them toTasmania;* the Polynesian race was preceded inits occupancy of the Pacific Islands by an unknownrace which left great monolithic monuments, as inFiji and in Easter Island; the American Indianswere preceded by the "Mound Builders"; andsimilarly in every part of the world it is difficultto get back to the first human inhabitants. Inthe thousands of centuries which separate the originof the earliest human types from the period ofwritten history, mankind had wandered over allparts of the earth.During this time the surface of the earth itself

suffered many changes; portions which are nowcovered by seas were then dry lands; isolatedislands were then connected with continents; fourgreat ice ages separated by interglacial epochs,each lasting for thousands of years, came and went;large portions of the northern hemisphere wereat times as inhospitable as central Greenland isto-day and again these regions were covered withforests and luxuriant vegetation and inhabitedby strange, extinct animals; and throughout allthese changes in the earth's surface and in itsliving inhabitants, primitive men discovered andoccupied practically every habitable portion of theglobe.The total human population of the earth has*Spcnccr, W. Baldwin. "Federal Handbook on Australia," 1914-


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38 PATHS AND POSSIBILITIESbeen estimated* to be about 1,700,000,000, distrib-uted among the different races as follows:White race about 550,000,000Yellow race about 500,000,000Brown race about 450,000,000Black race about 150,000,000Red race about 40,000,000

It should be noted that it is customary to countpersons of mixed white and colored blood as be-longing wholly to the colored races, so that thefigures given above rather minimize the whiteelement in the population of the globe.

In general the growth of population is correlatedwith the area occupied and with the agriculturaland industrial development of the people. Wherethere is much crowding, populations are eitherstationary or are growing slowly. Where there isa rich and abundant area, the growth of popula-tion is usually rapid. Tribes with antisocial ornomadic instincts, such as American Indians,Bedouins, and Gypsies are decreasing under thepressure of population and are destined ultimatelyto disappear, unless they adopt the habits of moresettled peoples.In China the population is practically at a stand-

still. It is growing in Japan and overflowing intoother countries, but on the whole the yellow race

* Stoddard, Lothrop. "The Rising Tide of Color Against WhiteWorld Supremacy," New York, 1920, p. 6.


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PATHS AND POSSIBILITIES 39is not increasing very rapidly in numbers. Fecun-dity is high but so, also, is mortality. In spite ofthe great area which it occupies the black race isnot increasing in numbers in Africa, whereas byimmigration and natural increase the white racein that continent is growing rapidly. Even in theUnited Stated the rate of increase of the blacksis not equal to that of the whites, for although thebirth-rate is high, the death-rate is also high.The white race with about one-third of the total

population of the globe occupies four-tenths of thehabitable land and has political control over nine-tenths of it.* In the more densely populatedportions of Europe the population is approachinga stationary condition, but in the wide areas ofAmerica, Africa, and Australasia it is expandingrapidly.

In spite of the occasional alarms which aresounded with regard to " race-suicide " it is evidentthat the white race is at present increasing morerapidly than any of the other human races. Thisis due not merely to the %larger area which it con-trols, but also to its greater agricultural, industrial,and scientific development. While the birth-rateis falling everywhere, the death-rate is falling morerapidly among whites than among other races.How long this greater growth of the white racemay go on no one can foresee, but certainly we

* Stoddard, L., loe. cit.


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40 PATHS AND POSSIBILITIESmay anticipate that it will continue until the rela-tively unoccupied areas which it now controls aremuch more densely populated. But in an indus-trial age it is not so much land area as sources ofenergy such as coal, oil, and water power thatcount most. Where these are abundant, thereare the "seats of power." Some of these havebeen rapidly exhausted in the white man's countriesand it is believed that great stores of them arefound in other lands, especially in China. Thisundoubtedly betokens a great industrial develop-ment in China in the near future and this in turnwill lead to a further increase of population inthat country.Most of our "race problems" are of relatively

recent origin and are caused chiefly by the pressureof population within certain centres and its over-flow into other lands as well as by the importationof cheap labor. The white man in particular hasforced himself on other races, and the pressure ofwhites into the lands of colored races has gonemuch farther than the reverse. Furthermore, thewhite man's demand for cheap labor is chiefly re-sponsible for the importation of colored races intothe lands of the whites and for the general mixingup of all races of mankind. The present competi-tion between races is a contest in the relative growthof populations and in economic progress rather thanin military power.


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PATHS AND POSSIBILITIES 41In all living things populations tend to increase

in geometrical ratio, while the limits of the habita-ble globe remain fixed. Migration may for a timerelieve this pressure of overpopulation, but itslimits are soon reached. In the case of man thecontrol and utilization of natural resources hasgreatly extended the possible limits of population,but it is evident that these resources are not indefi-nite in extent. The whole world must look for-ward to a time, at no distant date, when the limitsof population will be reached everywhere.

In his "Principles of Economics" (8th edition,page 1 80) Alfred Marshall says:Taking the present population of the world at one and a

half thousand millions; and assuming that its present rateof increase will continue (about 8 per 1,000 annually; seeRavenstein's paper before the British Association in 1890),we find that in less than 200 years it will amount to six thou-sand millions, or at the rate of about 200 to the square mileof fairly fertile land. (Ravenstein reckons 28 million squaremiles of fairly fertile land, and 14 millions of poor grass-lands. The first estimate is thought by many to be too high ;but allowing for this, if the less fertile land be reckoned infor what it is worth, the result will be about 30 million squaremiles as assumed above.) Meanwhile there will probablybe great improvements in the arts of agriculture; and, ifso, the pressure of population on the means of subsistencemay be held in check for about 200 years, but not longer.

Pearl* has shown that the growth of popula-tion in the United States may be represented very

* Pearl, R. Proceedings National Academy of Sciences, June, 1920.


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42 PATHS AND POSSIBILITIESaccurately by a long /-shaped curve, in which ourpresent population of about 100 millions falls nearthe middle point, and he predicts that "the maxi-mum population which continental United States,as now arealy limited, will ever have will be roughlytwice the present population." He estimates thatthis maximum will be reached in about 180 years,and that at that date " unless our food habitsradically change, or unless our agricultural pro-duction radically increases, it will be necessaryto import nearly or quite one-half of the caloriesnecessary for that population."

This is a different story from that which we havebeen accustomed to hear. No longer is it true that" Uncle Sam has land enough to give us all a farm,"and the time is not very far off only about sixhuman generations when the death-rate in thiscountry must equal the birth-rate, or our ddscen-dants of that date must emigrate. And where willthey go? By that time other parts of the worldwill be much more fully occupied, and other na-tions may choose to be more careful for their futurethan we have been for ours. And we thought wehad room enough for all the crowded peoples of theearth for all time to come ! This country will thenhave no immigration problem, but for hundreds ofyears more our descendants will have the racialproblems bequeathed to them by us, in order thatwe might "get rich quick" by importing cheap


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PATHS AND POSSIBILITIES 43foreign labor and by stripping our land of its naturalresources as rapidly as possible.The dangers of overpopulation have been em-phasized by many scientists since Malthus pub-lished his famous essay on this subject. In general,these warnings have been lightly regarded, owingchiefly to the enormous advances of science inmaking available natural resources. Many per-sons seem to think that these advances will go onindefinitely and that therefore populations canincrease indefinitely, but this is certainly not true !"The population question," says Huxley, "is thereal riddle of the Sphinx, to which no political(Edipus has as yet found the answer. In view ofthe ravages of the terrible monster, overmultipli-cation, all other riddles sink into insignificance." *Nature will, of course, solve this problem for

us if we do not solve it for ourselves. Apartfrom migration there are two ways, and only two,of preventing overpopulation by increasing thedeath-rate or decreasing the birth-rate. In allcivilized countries the death-rate has been decreas-ing during the past century, but if overcrowdingand underfeeding should occur the death-ratewill inevitably increase. In the older and morepopulous portions of the world the birth-rate hasalso been decreasing, especially during the past

* Huxley, T. H. "The Natural Inequalities of Men," CollectedEssays, New York, p. 328.


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44 PATHS AND POSSIBILITIEStwo or three generations. In the main this hasbeen due to voluntary causes, and in so far as itrepresents an intelligent and ethical control ofreproduction, and not mere selfishness, it is to becommended. Future ages may see a completereversal of the current legal aspects of birth-control; in a densely populated globe, instead ofdiscouraging this and forbidding the diffusion ofknowledge regarding it, the privilege of havingchildren may be strictly limited. Hitherto evolu-tionary progress has depended to a large extentupon overpopulation, the struggle for existenceand the survival of the fittest. In rational andmoral human societies this kind of natural selec-tion can never again be allowed to work as it hasdone in the past, but possibly overpopulation maybring about a rational solution of this problemalong the lines of eugenics and birth-control.Stoddard has said that the great danger to thewhite race in this struggle for supremacy is due tothe fact that the colored races can underline thewhites. But there is no evidence that the abso-lute requirements of food and clothing differ indifferent races. The basal metabolism as measuredin calories of food is not markedly greater for whitemen than for yellow or black men living underthe same conditions. No doubt the standards ofliving are at present much higher among whitethan among colored races. But standards of liv-


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PATHS AND POSSIBILITIES 45ing depend chiefly upon intelligence and resources.Within any and every race there are great individualvariations in the standards of living, and amongthe intelligent and well-to-do of different racesthese standards do not differ greatly. There arefew things which all types of mankind learn morequickly and willingly than to adopt higher stand-ards of living when they have the opportunity,and we may be sure that this will apply to thecolored races as well as to the poorer types of whites.One of the great dangers which confronts thewhole world is that standards of living, with de-mands for luxuries and leisure, are increasing muchmore rapidly than intelligence and social responsi-bility.

In the long run, supremacy will pass in everycommunity, nation, or race to the more intelligent,the more capable, the more ethical, rather than tothe best livers. It is only when high standardsof living spring from high standards of intelligenceand social ideals that they are not a menace ratherthan a blessing. Mere love of luxury will sap ourcivilization as it did that of ancient Greece andRome, and if it should affect the white race muchmore than the colored races, then indeed shouldwe have cause to fear for white leadership in theworld.

After all, in this struggle of races and peoples,there is reason to believe that success will ulti-


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46 PATHS,AND POSSIBILITIESmately rest with the intelligent, the capable, andthe ethical, and the attention of all who love theirrace should be centred upon raising the standardsof heredity, of education, and of social ideals ratherthan upon standards of living. I see no reason tosuppose that in these respects the white races willfall below the colored ones. The greatest dangerwhich faces any superior race is that of amalgama-tion with inferior stock and the consequent loweringof inherited capacities.


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HYBRIDIZATION OF RACESEXISTING races have arisen by mutation andhybridization, but they have been established by

the isolation of certain of these mutants or biotypes.The present tendency to the breaking down ofisolation and the commingling of races is a reversalof the processes by which those races were estab-lished. If in the past "God made of one bloodall nations of men," it is certain that at presentthere is being made from all nations one blood.By the interbreeding of various races and breedsthere has come to be a complicated intermixtureof racial characters in almost every human stock,and this process is going on to-day more rapidlyand extensively than ever before. Strictly speak-ing, there are no "pure" lines in any human group.If so-called "pure" English, Irish, Scotch, Dutch,German, Russian, French, Spanish, or Italianlines are traced back only a few generations theyare found to include many foreign strains, and thisis especially true of American families, even thoseof "purest" blood.By this commingling of different lines manynew combinations of characters are produced and

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48 PATHS AND POSSIBILITIESsome of these combinations may be superior toeither parental type, while others may be inferior.In the language of genetics all the offspring ofparents of different breeds or strains are "hy-brids," though in common usage this term is ap-plied only where the parents belong to differentspecies, subspecies, or races. Mongrels or hy-brids are not always inferior to their parents norare these terms necessarily ones of reproach, aspopular usage would indicate. Bateson says thatmost of the new varieties of cultivated plants arethe result of deliberate crossing. This is the proc-ess which Burbank has followed with such wonder-ful success in his experiments. Where two breedshave certain qualities which are desirable and otherswhich are undesirable, it is often possible by cross-ing them to get a few hybrids in which the goodqualities of both breeds are combined and the badones eliminated. Many species of domesticatedanimals and cultivated plants are of hybrid origin;among these are probably dogs, cats, cattle, horses,sheep, pigs, poultry; wheat, oats, rice, plums,cherries, etc.We are quite accustomed, and more or less

reconciled, to the intermingling of European races,but the average white person, at least, is unableto look upon the commingling of blood of the pri-mary races of mankind without serious misgivingsas to its effect on the future of the species. Within


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PATHS AND POSSIBILITIES 49certain limits cross-breeding of animals and plantsseems to produce increased vigor,* and there is nodoubt that highly desirable combinations of thecharacters of different breeds can thus be made.It is generally believed by Englishmen that theAnglo-Saxon, Anglo-Norman, Norman-French,Scotch-Irish combinations were very good ones,and Americans would point to the good results ofthe crossing of English, Scotch, Irish, French,Dutch, German, and Scandinavian stocks.But it is a general belief that the crossing of

distinct species or subspecies does not lead toimprovement, and it is said that the actual resultsof the crossing of white, black, and red races inSouth America, Mexico, and the West Indies, orof brown, yellow, and white races in Polynesia,has not produced a type superior to the best ofthose that entered into the combination. Stoddard(p. 116) says that "Most informed observers agreethat the mixed-bloods of Latin America are dis-tinctly inferior to the whites. This applies toboth mestizos and mulattoes, albeit the mestizo(the cross between white and Indian) seems lessinferior than the mulatto the cross betweenwhite and black. As for the zambo, the Indian-negro cross, everybody is agreed that it is a verybad one/' On this subject he quotes Louis Agassizas follows: "Let any one who doubts the evil of

* This has been called in question by King, East, and others.


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So PATHS AND POSSIBILITIESthis mixture of races, and is inclined from mistakenphilanthropy to break down all barriers betweenthem, come to Brazil. He cannot deny the deteri-oration consequent upon the amalgamation ofraces, more wide-spread here than in any countryin the world, and which is rapidly effacing the bestqualities of the white man, the negro, and theIndian, leaving a mongrel, nondescript type, defi-cient in physical and mental energy."

Nevertheless it must be remembered that inmost instances the white blood, at least, whichentered into these combinations was not of veryhigh quality, and it is hard to avoid the conclusionthat Mendelian heredity, which is operative hereas everywhere else, will lead to all kinds of combi-nations good, bad, and indifferent even amongthe offspring of the same parents, and much moreamong offspring of different parents. It is highlyprobable that while some of these hybrids may showall the bad qualities of both parents, others mayshow the good qualities of both and indeed inthis respect resemble the children in any pure-bred family. But it is practically certain that thegeneral or average results of the crossing of a su-perior and an inferior race are to strike a balancesomewhere between the two. This is no contra-diction of the principles of Mendelian inheritancebut rather the application of these principles to ageneral population. The general effect of thehybridization of races cannot fail to lead to a lower-


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PATHS AND POSSIBILITIES 51ing of the qualities of the higher race and a raisingof the qualities of the lower one.Which are the* higher and which the lower racesof mankind must depend largely upon the pointof view and the qualities under consideration.No race has a monopoly of good or bad qualities;all that can be said is that certain traits are morefrequently found in one race than in another.

In love of adventure, of discovery, and of freedomwithin the limits of social order the white race isprobably supreme, and these qualities under favor-able environment have led to its great scientific,industrial, and political development. In virility,conservatism, and reverence for social obligationsthe yellow race, as a whole, is probably superiorto the white. If the white race worships liberty,the yellow race deifies duty; if the former is sociallycentrifugal, the latter is centripetal. The brown,red, and black races each have their characteristicvirtues and defects which have become proverbial.Every race has contributed something of value tocivilization, though there can be no doubt thatthe white, yellow, and brown races lead, and prob-ably in the order named.No doubt if all the good qualities of differentraces could be combined and all of the bad quali-ties eliminated the result would be a type greatlysuperior to any existing race. In domestic animalsand cultivated plants such combinations and elimi-nations are frequently made, and if a higher power


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52 PATHS AND POSSIBILITIESshould deal with man as he does with his domesti-cated animals, no doubt it would be possible tobring about similar results in the human species.Even if we are horrified by the thought, we can-

not hide the fact that all present signs point to anintimate commingling of all existing human typeswithin the next five or ten thousand years at most.Unless we can re-establish geographical isolationof races, we cannot prevent their interbreeding.By rigid laws excluding immigrants of other races,such as they have at present in New Zealand andAustralia, it may be possible for a time to main-tain the purity of the white race in certain countries,but with the constantly increasing intercommuni-cations between all lands and peoples such artificialbarriers will probably prove as ineffectual in thelong run as the Great Wall of China. The races ofthe world are not drawing apart but together, andit needs only the vision that will look ahead a fewthousand years to see the blending of all racialcurrents into a common stream.What the relative contributions of existing races

to this composite race will be is an interestingspeculation. Relative viability and fecundity ofdifferent races and hybrids as well as psychologicalaffinities and antipathies are important factors inthis problem. There is in general much less senti-ment for racial purity on the part of colored racesthan in the case of the white race, and on the part


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PATHS AND POSSIBILITIES 53of white men than of white women, consequentlywhite blood will diffuse more rapidly through col-ored populations than colored blood through thewhite. More important still is the fact that forcenturies to come Europe, North America, andAustralasia will continue to be the centres of thewhite race; China and Japan of the yellow race;and Africa of the black race, but on the bordersaround these centres, where the races meet andoverlap, there will be miscegenation. In thesecentres of the white, yellow, and black races we mayassume that the populations will for a long timeremain predominantly white, yellow, or black, butwith increasing infiltration of foreign blood. Thelonger this segregation can be maintained the larger,other factors being equal, will become the ratio ofwhites to other races and the greater will be theircontribution to the composite race. Every con-sideration should lead those who believe in thesuperiority of the white race to strive to preserveits purity and to establish and maintain the segre-gation of the races, for the longer this is maintainedthe greater the preponderance of the white racewill be, but in the end amalgamation of all racesin all parts of the world will probably be as completeas in the case of Greeks, Latins, Saracens, Nor-mans, and Africans in Sicily and Southern Italy.


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vfPRESENT AND FUTURE EVOLUTION OFMAN

A. PHYSICAL EVOLUTIONSINCE the beginnings of recorded history there

have been very few and wholly minor evolutionarychanges in the body of man. Chief among theseare the decreasing size of the little toe and perhapsa corresponding increase in the size of the greattoe; decreasing size and strength of the teeth,especially of the wisdom teeth; and probably ageneral lowering of the perfection of sense-organs.*

These changes are in the main degenerative onesdue to the less rigid elimination of physical im-perfections under conditions of civilization than ina state of barbarism or savagery. Such changesare insignificant as compared with the enormouschanges which led to the evolution of man fromprehuman ancestors.

Individual variations due to hybridization or toenvironmental influences are always present butthey have little evolutionary value. By hybridi-zation of various races and stocks there has cometo be a complicated intermixture of racial charac-

*See Osborn, H. F. "Contemporary Evolution of Man."54


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PATHS AND POSSIBILITIES 55ters; new combinations of characters are thusproduced, but new individual characters have notbeen evolved by hybridization. By changes inenvironment modifications have -been produced indevelopment but not in heredity, these are fluctua-tions and not mutations.To a certain extent evolution may be regarded as

a response of the organism to environment, whetherwe have regard to the origin of mutations in thegermplasm or to the survival of mutations afterthey have arisen. But in the case of man thephysical environment has probably far less evolu-tionary value than in lower animals, for by meansof intelligence man is able, to a great extent, tocontrol his environment. In cold climates he doesnot need to grow a thicker coat of hair in order tokeep from freezing to death; he can put on or offheavier clothing, as he pleases; he can even changethe climate of his residence to suit his needs.Shortage of one kind of food does not compel himto undergo changes of teeth and stomach to fithim to use other foods; he can produce more foodof the first kind or can so change and modify newkinds of food that the old digestive system can dealwith them. Therefore to the extent that evolutiondepends upon changing physical environment, manis to a great extent removed from such influencessince he can control his environment.Furthermore the greatest of the directing factors


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$6 PATHS AND POSSIBILITIESof evolution, namely natural selection, or the sur-vival of the fittest individuals, has been largelynullified in civilized society. By the most extraor-dinary efforts we manage to save the weak anddeformed in body, the feeble-minded and insane,the evil and antisocial. We are just beginning torealize that intelligent human selection must takethe place of natural selection and that the most un-fit must be prevented from perpetuating their kind;but is it not evident that the stream cannot risehigher than its source, and that the most that canbe expected from such artificial selection is thatmankind as a whole shall approach somewhatnearer to the level of the best individuals of thepast and present ?

Eugenics

Many persons who recognize that human evolu-tion is not progressing favorably look to eugenics,or selective mating, as the best available method ofpromoting human progress. And there is no doubtthat if the same methods which have been appliedto the breeding of domestic animals and plantscould be applied to man, many important improve-ments in the human stock could be effected.Chiefly by means of selective breeding, all of thebest types of domesticated animals and cultivatedplants have been produced, or rather made up andisolated, for the breeder can only wait and watch


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PATHS AND POSSIBILITIES 57for favorable mutations to appear; once they haveappeared, he can by appropriate cross-breedingcombine these new qualities with other desirableones, and after he has made up a desirable combi-nation he can, by close inbreeding, perpetuate itand thus produce a new breed or race.

Mutations of many sorts, good, bad, and indiffer-ent, are occurring in the human race, and by cross-breeding good combinations as well as bad ones areproduced. Under a system of selective matingcomparable to that practised by animal and plantbreeders, it would be possible to perpetuate thegood combinations and eliminate the bad and thusto improve the human breed, but this would in-volve such changes in our ideas of monogamy andmorality as are scarcely conceivable. And evensuch a thoroughgoing system of eugenics would notreally lead to progressive evolution, with the forma-tion of new characters and the emergence of a newtype of man, but only to new combinations of exist-ing characters.One of the serious difficulties in the way of a really

thoroughgoing system of eugenics is the impossi-bility of determining what combinations are reallybest and how to bring them about. Until we knowvastly more about the genesis of personality thanwe do now, positive eugenics must be a relativelyweak and blundering procedure. It would probab-ly have robbed the world of some of its greatest


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58 PATHS AND POSSIBILITIESmen, whose antecedents were most unpromising.The most intelligent eugenicist cannot tell us howto get the best results; he can rarely, if ever, getchildren of his own that are entirely satisfactory;usually the most that he can do is to tell us howto avoid the worst results. As Huxley says: "Thepoints of a good or bad citizen are really far harderto discern than those of a puppy or a short-horncalf. ... I sometimes wonder whether peoplewho talk so freely about extirpating the unfit, everdispassionately consider their own history. Surelyone must be very 'fit' indeed not to know of anoccasion, or perhaps two, in one's life when it wouldhave been only too easy to qualify for a placeamong the unfit."*

In all domestic animals and cultivated plantsit is found that the breeder can only sort out andrecombine the characters which are given; hecannot make new characters or hereditary factors,and consequently he soon reaches the limits of thepossible improvement of a breed and must thenwait until a new variation or mutation appears.Similarly the eugenicist, even if he could controlhuman breeding as thoroughly as the animalbreeder, could not expect to bring about indefiniteimprovement, but would soon reach a limit in everyline beyond which he could not go until a newmutation furnished the material. And even muta-

* Huxley, T. H. "Evolution and Ethics," p. 39.


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PATHS AND POSSIBILITIES 59tions have their limits, beyond which they cannotgo without upsetting the entire organic equilibrium.

It is conceivable, though not probable, that thetime may come when we may learn how to producehuman mutations, possibly how to produce goodmutations. If this should ever happen we shouldhave a wonderful opportunity to speed up andcontrol human evolution. But at present this ismerely a dream, and there is no likelihood that itwill ever be realized. Important, therefore, aseugenics is in bringing about better combinationsof hereditary traits, it does not hold forth the prom-ise of endless progress.From all these points of view it is evident that

the conception of unlimited evolutionary progressin any particular line, whether among plants,animals, or men is a mere chimera. In every lineof progress a limit is sooner or later reached, beyondwhich it is not possible to go. Further progress,if it occurs at all, must be in other lines.For at least one hundred cen

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