speaks in this university of ancient renown, can not but feel with
peculiar vividness the interest and charm of his surroundings, fraught
as they are with a thousand associations. Your great universities, and
all the memories that make them great, are living realities in the
minds of scores of thousands of men who have never seen them and who
dwell across the seas in other lands. Moreover, these associations
are no stronger in the men of English stock than in those who are
not. My people have been for eight generations in America; but in one
thing I am like the Americans of to-morrow, rather than like many of
the Americans of to-day; for I have in my veins the blood of men who
came from many different European races. The ethnic make-up of our
people is slowly changing, so that constantly the race tends to become
more and more akin to that of those Americans who like myself are
of the old stock but not mainly of English stock. Yet I think that,
as time goes by, mutual respect, understanding, and sympathy among
the English-speaking peoples grow greater and not less. Any of my
ancestors, Hollander or Huguenot, Scotchman or Irishman, who had come
to Oxford in “the spacious days of great Elizabeth,” would have felt
far more alien than I, their descendant, now feel. Common heirship in
the things of the spirit makes a closer bond than common heirship in
the things of the body.
[2] Delivered at Oxford, June 7, 1910. This was the Romanes
Lecture for 1910, and has been published by the Oxford
University Press, with whose permission it is included in
this volume.
More than ever before in the world’s history we of to-day seek to
penetrate the causes of the mysteries that surround not only mankind
but all life, both in the present and the past. We search, we peer, we
see things dimly; here and there we get a ray of clear vision, as we
look before and after. We study the tremendous procession of the ages,
from the immemorial past when in “cramp elf and saurian forms” the
creative forces “swathed their too-much power,” down to the yesterday,
a few score thousand years distant only, when the history of man became
the overwhelming fact in the history of life on this planet; and
studying we see strange analogies in the phenomena of life and death,
of birth, growth, and change, between those physical groups of animal
life which we designate as species, forms, races, and the highly
complex and composite entities which rise before our minds when we
speak of nations and civilizations.
It is this study which has given science its present-day prominence.
In the world of intellect, doubtless, the most marked features in the
history of the past century have been the extraordinary advances in
scientific knowledge and investigation, and in the position held by the
men of science with reference to those engaged in other pursuits. I
am not now speaking of applied science; of the science, for instance,
which, having revolutionized transportation on the earth and the
water, is now on the brink of carrying it into the air; of the science
that finds its expression in such extraordinary achievements as the
telephone and the telegraph; of the sciences which have so accelerated
the velocity of movement in social and industrial conditions--for
the changes in the mechanical appliances of ordinary life during the
last three generations have been greater than in all the preceding
generations since history dawned. I speak of the science which has
no more direct bearing upon the affairs of our every-day life than
literature or music, painting or sculpture, poetry or history. A
hundred years ago the ordinary man of cultivation had to know something
of these last subjects; but the probabilities were rather against his
having any but the most superficial scientific knowledge. At present
all this has changed, thanks to the interest taken in scientific
discoveries, the large circulation of scientific books, and the
rapidity with which ideas originating among students of the most
advanced and abstruse sciences become, at least partially, domiciled in
the popular mind.
Another feature of the change, of the growth in the position of
science in the eyes of every one, and of the greatly increased respect
naturally resulting for scientific methods, has been a certain
tendency for scientific students to encroach on other fields. This
is particularly true of the field of historical study. Not only have
scientific men insisted upon the necessity of considering the history
of man, especially in its early stages, in connection with what biology
shows to be the history of life, but furthermore there has arisen
a demand that history shall itself be treated as a science. Both
positions are in their essence right; but as regards each position, the
more arrogant among the invaders of the new realm of knowledge take an
attitude to which it is not necessary to assent. As regards the latter
of the two positions, that which would treat history henceforth merely
as one branch of scientific study, we must of course cordially agree
that accuracy in recording facts and appreciation of their relative
worth and interrelationship are just as necessary in historical
study as in any other kind of study. The fact that a book, though
interesting, is untrue, of course removes it at once from the category
of history, however much it may still deserve to retain a place in the
always desirable group of volumes which deal with entertaining fiction.
But the converse also holds, at least to the extent of permitting us to
insist upon what would seem to be the elementary fact that a book which
is written to be read should be readable. This rather obvious truth
seems to have been forgotten by some of the more zealous scientific
historians, who apparently hold that the worth of a historical book
is directly in proportion to the impossibility of reading it, save as
a painful duty. Now I am willing that history shall be treated as a
branch of science, but only on condition that it also remains a branch
of literature; and, furthermore, I believe that as the field of science
encroaches on the field of literature there should be a corresponding
encroachment of literature upon science; and I hold that one of the
great needs, which can only be met by very able men whose culture is
broad enough to include literature as well as science, is the need of
books for scientific laymen. We need a literature of science which
shall be readable. So far from doing away with the school of great
historians, the school of Polybius and Tacitus, Gibbon and Macaulay,
we need merely that the future writers of history, without losing the
qualities which have made these men great, shall also utilize the
new facts and new methods which science has put at their disposal.
Dryness is not in itself a measure of value. No “scientific” treatise
about St. Louis will displace Joinville, for the very reason that
Joinville’s place is in both history and literature; no minute study
of the Napoleonic wars will teach us more than Marbot--and Marbot is
as interesting as Walter Scott. Moreover, certain at least of the
branches of science should likewise be treated by masters in the art of
presentment, so that the layman interested in science, no less than the
layman interested in history, shall have on his shelves classics which
can be read. Whether this wish be or be not capable of realization,
it assuredly remains true that the great historian of the future must
essentially represent the ideal striven after by the great historians
of the past. The industrious collector of facts occupies an honorable,
but not an exalted, position, and the scientific historian who produces
books which are not literature must rest content with the honor,
substantial, but not of the highest type, that belongs to him who
gathers material which some time some great master shall arise to use.
Yet, while freely conceding all that can be said of the masters of
literature, we must insist upon the historian of mankind working in the
scientific spirit, and using the treasure-houses of science. He who
would fully treat of man must know at least something of biology, of
the science that treats of living, breathing things; and especially of
that science of evolution which is inseparably connected with the great
name of Darwin. Of course, there is no exact parallelism between the
birth, growth, and death of species in the animal world, and the birth,
growth, and death of societies in the world of man. Yet there is a
certain parallelism. There are strange analogies; it may be that there
are homologies.
How far the resemblances between the two sets of phenomena are
more than accidental, how far biology can be used as an aid in the
interpretation of human history, we can not at present say. The
historian should never forget, what the highest type of scientific man
is always teaching us to remember, that willingness to admit ignorance
is a prime factor in developing wisdom out of knowledge. Wisdom is
advanced by research which enables us to add to knowledge; and,
moreover, the way for wisdom is made ready when men who record facts of
vast but unknown import, if asked to explain their full significance,
are willing frankly to answer that they do not know. The research which
enables us to add to the sum of complete knowledge stands first;
but second only stands the research which, while enabling us clearly
to pose the problem, also requires us to say that with our present
knowledge we can offer no complete solution.
Let me illustrate what I mean by an instance or two taken from one of
the most fascinating branches of world-history, the history of the
higher forms of life, of mammalian life, on this globe.
Geologists and astronomers are not agreed as to the length of time
necessary for the changes that have taken place. At any rate, many
hundreds of thousands of years, some millions of years, have passed
by since in the eocene, at the beginning of the tertiary period, we
find the traces of an abundant, varied, and highly developed mammalian
life on the land masses out of which have grown the continents as
we see them to-day. The ages swept by, until, with the advent of
man substantially in the physical shape in which we now know him,
we also find a mammalian fauna not essentially different in kind,
though widely differing in distribution, from that of the present day.
Throughout this immense period form succeeds form, type succeeds type,
in obedience to laws of evolution, of progress and retrogression, of
development and death, which we as yet understand only in the most
imperfect manner. As knowledge increases our wisdom is often turned
into foolishness, and many of the phenomena of evolution which seemed
clearly explicable to the learned master of science who founded these
lectures, to us nowadays seem far less satisfactorily explained. The
scientific men of most note now differ widely in their estimates of the
relative parts played in evolution by natural selection, by mutation,
by the inheritance of acquired characteristics; and we study their
writings with a growing impression that there are forces at work which
our blinded eyes wholly fail to apprehend; and where this is the case
the part of wisdom is to say that we believe we have such and such
partial explanations, but that we are not warranted in saying that we
have the whole explanation. In tracing the history of the development
of faunal life during this period, the age of mammals, there are some
facts which are clearly established, some great and sweeping changes
for which we can with certainty ascribe reasons. There are other facts
as to which we grope in the dark, and vast changes, vast catastrophes,
of which we can give no adequate explanation.
Before illustrating these types, let us settle one or two matters of
terminology. In the changes, the development and extinction, of species
we must remember that such expressions as “a new species,” or as “a
species becoming extinct,” are each commonly and indiscriminately
used to express totally different and opposite meanings. Of course
the “new” species is not new in the sense that its ancestors appeared
later on the globe’s surface than those of any old species tottering to
extinction. Phylogenetically, each animal now living must necessarily
trace its ancestral descent back through countless generations, through
eons of time, to the early stages of the appearance of life on the
globe. All that we mean by a “new” species is that from some cause, or
set of causes, one of these ancestral stems slowly or suddenly develops
into a form unlike any that has preceded it; so that, while in one form
of life the ancestral type is continuously repeated and the old species
continues to exist, in another form of life there is a deviation from
the ancestral type and a new species appears.
Similarly, “extinction of species” is a term which has two entirely
different meanings. The type may become extinct by dying out and
leaving no descendants. Or it may die out because as the generations
go by there is change, slow or swift, until a new form is produced.
Thus in one case the line of life comes to an end. In the other case it
changes into something different. The huge titanothere, and the small
three-toed horse, both existed at what may roughly be called the same
period of the world’s history, back in the middle of the mammalian age.
Both are extinct in the sense that each has completely disappeared
and that nothing like either is to be found in the world to-day. But
whereas all the individual titanotheres finally died out, leaving no
descendants, a number of the three-toed horses did leave descendants,
and these descendants, constantly changing as the ages went by, finally
developed into the highly specialized one-toed horses, asses, and
zebras of to-day.
The analogy between the facts thus indicated and certain facts in
the development of human societies is striking. A further analogy
is supplied by a very curious tendency often visible in cases of
intense and extreme specialization. When an animal form becomes
highly specialized, the type at first, because of its specialization,
triumphs over its allied rivals and its enemies, and attains a great
development; until in many cases the specialization becomes so extreme
that from some cause unknown to us, or at which we merely guess, it
disappears. The new species which mark a new era commonly come from the
less specialized types, the less distinctive, dominant, and striking
types, of the preceding era.
When dealing with the changes, cataclysmic or gradual, which divide one
period of paleontological history from another, we can sometimes assign
causes, and again we can not even guess at them. In the case of single
species, or of faunas of very restricted localities, the explanation
is often self-evident. A comparatively slight change in the amount
of moisture in the climate, with the attendant change in vegetation,
might readily mean the destruction of a group of huge herbivores with
a bodily size such that they needed a vast quantity of food, and with
teeth so weak or so peculiar that but one or two kinds of plants could
furnish this food. Again, we now know that the most deadly foes of the
higher forms of life are various lower forms of life, such as insects,
or microscopic creatures conveyed into the blood by insects. There
are districts in South America where many large animals, wild and
domestic, can not live because of the presence either of certain ticks
or of certain baleful flies. In Africa there is a terrible genus of
poison fly, each species acting as the host of microscopic creatures
which are deadly to certain of the higher vertebrates. One of these
species, though harmless to man, is fatal to all domestic animals,
and this although harmless to the closely related wild kinsfolk of
these animals. Another is fatal to man himself, being the cause of
the “sleeping-sickness” which in many large districts has killed out
the entire population. Of course the development or the extension
of the range of any such insects, and any one of many other causes
which we see actually at work around us, would readily account for
the destruction of some given species or even for the destruction of
several species in a limited area of country.
When whole faunal groups die out over large areas, the question is
different, and may or may not be susceptible of explanation with the
knowledge we actually possess. In the old arctogæal continent, for
instance, in what is now Europe, Asia, and North America, the glacial
period made a complete, but of course explicable, change in the faunal
life of the region. At one time the continent held a rich and varied
fauna. Then a period of great cold supervened, and a different fauna
succeeded the first. The explanation of the change is obvious.
But in many other cases we can not so much as hazard a guess at why
a given change occurred. One of the most striking instances of these
inexplicable changes is that afforded by the history of South America
toward the close of the tertiary period. For ages South America had
been an island by itself, cut off from North America at the very
time that the latter was at least occasionally in land communication
with Asia. During this time a very peculiar fauna grew up in South
America, some of the types resembling nothing now existing, while
others are recognizable as ancestral forms of the ant-eaters, sloths,
and armadillos of to-day. It was a peculiar and diversified mammalian
fauna, of, on the whole, rather small species, and without any
representatives of the animals with which man has been most familiar
during his career on this earth.
Toward the end of the tertiary period there was an upheaval of land
between this old South American island and North America, near what
is now the Isthmus of Panama, thereby making a bridge across which
the teeming animal life of the northern continent had access to this
queer southern continent. There followed an inrush of huge, or swift,
or formidable creatures which had attained their development in the
fierce competition of the arctogæal realm. Elephants, camels, horses,
tapirs, swine, sabre-toothed tigers, big cats, wolves, bears, deer,
crowded into South America, warring each against the other incomers
and against the old long-existing forms. A riot of life followed. Not
only was the character of the South American fauna totally changed by
the invasion of these creatures from the north, which soon swarmed over
the continent, but it was also changed through the development wrought
in the old inhabitants by the severe competition to which they were
exposed. Many of the smaller or less capable types died out. Others
developed enormous bulk or complete armor protection, and thereby saved
themselves from the new beasts. In consequence, South America soon
became populated with various new species of mastodons, sabre-toothed
tigers, camels, horses, deer, cats, wolves, hooved creatures of strange
shapes, and some of them of giant size, all of these being descended
from the immigrant types; and side by side with them there grew up
large autochthonous ungulates, giant ground-sloths well-nigh as large
as elephants, and armored creatures as bulky as an ox but structurally
of the armadillo or ant-eater type; and some of these latter not only
held their own, but actually in their turn wandered north over the
isthmus and invaded North America. A fauna as varied as that of Africa
to-day, as abundant in species and individuals, even more noteworthy,
because of its huge size or odd type, and because of the terrific
prowess of the more formidable flesh-eaters, was thus developed in
South America, and flourished for a period which human history would
call very long indeed, but which geologically was short.
Then, for no reason that we can assign, destruction fell on this
fauna. All the great and terrible creatures died out, the same fate
befalling the changed representatives of the old autochthonous fauna
and the descendants of the migrants that had come down from the north.
Ground-sloth and glyptodon, sabre-tooth, horse and mastodon, and all
the associated animals of large size vanished, and South America,
though still retaining its connection with North America, once again
became a land with a mammalian life small and weak compared to that
of North America and the Old World. Its fauna is now marked, for
instance, by the presence of medium-sized deer and cats, fox-like
wolves, and small camel-like creatures, as well as by the presence of
small armadillos, sloths, and ant-eaters. In other words, it includes
diminutive representatives of the giants of the preceding era, both
of the giants among the older forms of mammalia, and of the giants
among the new and intrusive kinds. The change was wide-spread and
extraordinary, and with our present means of information it is wholly
inexplicable. There was no ice age, and it is hard to imagine any cause
which would account for the extinction of so many species of huge
or moderate size, while smaller representatives, and here and there
medium-sized representatives, of many of them were left.
Now as to all of these phenomena in the evolution of species, there
are, if not homologies, at least certain analogies, in the history
of human societies, in the history of the rise to prominence, of the
development and change, of the temporary dominance, and death or
transformation, of the groups of varying kind which form races or
nations. Here, as in biology, it is necessary to keep in mind that we
use each of the words “birth” and “death,” “youth” and “age,” often
very loosely, and sometimes as denoting either one of two totally
different conceptions. Of course, in one sense there is no such thing
as an “old” or a “young” nation, any more than there is an “old” or
“young” family. Phylogenetically, the line of ancestral descent must be
of exactly the same length for every existing individual, and for every
group of individuals, whether forming a family or a nation. All that
can properly be meant by the terms “new” and “young” is that in a given
line of descent there has suddenly come a period of rapid change. This
change may arise either from a new development or transformation of the
old elements, or else from a new grouping of these elements with other
and varied elements; so that the words “new” nation or “young” nation
may have a real difference of significance in one case from what they
have in another.
As in biology, so in human history, a new form may result from the
specialization of a long-existing, and hitherto very slowly changing,
generalized or non-specialized form; as, for instance, occurs when
a barbaric race from a variety of causes suddenly develops a more
complex cultivation and civilization. This is what occurred, for
instance, in western Europe during the centuries of the Teutonic and,
later, the Scandinavian ethnic overflows from the north. All the
modern countries of western Europe are descended from the states
created by these northern invaders. When first created they would be
called “new” or “young” states in the sense that part or all of the
people composing them were descended from races that hitherto had not
been civilized, and that therefore, for the first time, entered on
the career of civilized communities. In the southern part of western
Europe the new states thus formed consisted in bulk of the inhabitants
already in the land under the Roman Empire; and it was here that the
new kingdoms first took shape. Through a reflex action their influence
then extended back into the cold forests from which the invaders had
come, and Germany and Scandinavia witnessed the rise of communities
with essentially the same civilization as their southern neighbors;
though in those communities, unlike the southern communities, there
was no infusion of new blood, so that the new civilized nations which
gradually developed were composed entirely of members of the same races
which in the same regions had for ages lived the life of a slowly
changing barbarism. The same was true of the Slavs and the Slavonized
Finns of eastern Europe, when an infiltration of Scandinavian leaders
from the north, and an infiltration of Byzantine culture from the
south, joined to produce the changes which have gradually, out of the
little Slav communities of the forest and the steppe, formed the
mighty Russian Empire of to-day.