At the end of the nineteenth century, the age of 'natural science,' the
department of knowledge that has made most progress is zoology. From
zoology has arisen the study of transformism, which now dominates the
whole of biology. Lamarck[1] laid its foundation in 1809, and forty
years ago Charles Darwin obtained for it a recognition which is now
universal. It is not my task to repeat the well-known principles of
Darwinism. I am not concerned to explain the scientific value of the
whole theory of descent. The whole of our biological study is pervaded
by it. No general problem in zoology and botany, in anatomy and
physiology, can be discussed without the question arising, How has this
problem originated? What are the real causes of its development?
[1] See note, p. 80.
This question was almost unknown seventy years ago, when Charles
Darwin, the great reformer of biology, began his academical career at
Cambridge as a student of theology. In the same year, 1828, Carl Ernst
von Baer[2] published in Germany his classical work on the embryology
of animals, the first successful attempt to elucidate by 'observation
and reflection' the mysterious origin of the animal body from the
egg, and to explain in every respect the 'history of the growing
individuality.' Darwin at that time had no knowledge of this great
advance, and he could not divine that forty years later embryology
would be one of the strongest supports of his own life's work--of that
very theory of transformism which, founded by Lamarck in the year of
Darwin's birth, was accepted with enthusiasm by Charles's grandfather
Erasmus. There is no doubt that of all the celebrated naturalists of
the nineteenth century Darwin achieved the greatest success, and we
should be justified in designating the last forty years as the Age of
Darwin.
[2] See note, p. 89.
In searching for the causes of this unexampled success, we must clearly
separate three sets of considerations: first, the comprehensive reform
of Lamarck's transformism, and its firm establishment by the many
arguments drawn from modern biology; secondly, the construction of the
new theory of selection, as established by Darwin, and independently
by Alfred Wallace (a theory called Darwinism in the proper sense);
thirdly, the deduction of anthropogeny, that most important conclusion
of the theory of descent, the value of which far surpasses all the
other truths in evolution.
It is the third point of Darwin's theory that I shall discuss here; and
I shall discuss it chiefly with the intention of examining critically
the evidence and the different conclusions which at present represent
our scientific knowledge of the descent of man and of the different
stages of his animal pedigree.
It is now generally admitted that this problem is the most important
of all biological questions. Huxley was right when in 1863 he called
it the question of questions for mankind. The problem which underlies
all others, and is more deeply interesting than any other, is as
to the place which man occupies in nature and his relations to the
universe of things. 'Whence our race has come; what are the limits of
our power over nature, and of nature's power over us; to what goal are
we tending--these are the problems which present themselves anew and
with undiminished interest to every man born into the world.' This
impressive view was explained by Huxley thirty-five years ago in his
three celebrated essays on 'Evidence as to Man's Place in Nature.' The
first is entitled 'On the Natural History of the Man-like Apes'; the
second, 'On the Relations of Man to the Lower Animals'; the third, 'On
some Fossil Remains of Man.' Darwin himself felt the burden of these
problems as much as Huxley; but in his chief work, 'On the Origin of
Species,' in 1859, he had purposely only just touched them, suggesting
that the theory of descent would shed light upon the origin of man and
his history. Twelve years later, in his celebrated work on 'The Descent
of Man, and Selection in Relation to Sex,' Darwin discussed fully and
ingeniously all the different sides of this 'question of questions'
from the morphological, historical, physiological, and psychological
points of view. As early as 1866 I myself had applied in the _Generelle
Morphologie der Organismen_ the theory of transformism to anthropology,
and had shown that the fundamental law of biogeny claims the same
value for man as for all the other animals. The intimate causal
connection between ontogeny and phylogeny, between the development of
the individual and the history of its ancestors, enables us to gain
a safe and certain knowledge of our ancestral series. I had at that
time distinguished in this series ten chief degrees of vertebrate
organization. I attributed the highest importance to the logical
connection of anthropogeny with transformism. If the latter be true,
the truth of the former is absolute. 'Our theory that man is descended
from lower vertebrates, and immediately from apes or primates, is a
case of special _deduction_ which follows with absolute certainty from
the general _induction_ of the theory of descent.' The full proof and
detailed explanation of this view was afterwards given in my 'History
of Natural Creation,' and especially in my 'Anthropogeny.'[3] Lastly,
it has received an ample scientific and critical foundation in the
third part of my 'Systematic Phylogeny.'[3]
[3] See notes, pp. 102, 106
During the forty years which have elapsed since Darwin's first
publication of his theories an enormous literature, discussing the
_general problems_ of transformism as well as its special application
to man, has been published. In spite of the wide divergence of the
different views, all agree in one main point: the natural development
of man cannot be separated from general transformism. There are only
two possibilities. Either all the various species of animals and
plants have been created independently by supernatural forces (and
in this case the creation of man also is a miracle); or the species
have been produced in a natural way by transmutation, by adaptation
and progressive heredity (and in this case man also is descended from
other vertebrates, and immediately from a series of primates). We are
absolutely convinced that only the latter theory is fully scientific.
To prove its truth, we have to examine critically the strength of the
different arguments claimed for it.