Darwinism | Page 8

a swallow from a goose. But the vertebrate
animals, the mollusca, and the insects, are so radically distinct in their
whole organisation and in the very plan of their structure, that objectors
may not unreasonably doubt whether they can all have been derived
from a common ancestor by means of the very same laws as have
sufficed for the differentiation of the various species of birds or of
reptiles.
The Change of Opinion effected by Darwin.
The point I wish especially to urge is this. Before Darwin's work
appeared, the great majority of naturalists, and almost without
exception the whole literary and scientific world, held firmly to the
belief that species were realities, and had not been derived from other
species by any process accessible to us; the different species of crow
and of violet they are now, and to have originated by some totally
unknown process so far removed from ordinary reproduction that it was
usually spoken of as "special creation." There was, then, no question of
the origin of families, orders, and classes, because the very first step of
all, the "origin of species," was believed to be an insoluble problem.
But now this is all changed. The whole scientific and literary world,
even the whole educated public, accepts, as a matter of common
knowledge, the origin of species from other allied species by the
ordinary process of natural birth. The idea of special creation or any
altogether exceptional mode of production is absolutely extinct! Yet
more: this is held also to apply to many higher groups as well as to the
species of a genus, and not even Mr. Darwin's severest critics venture
to suggest that the primeval bird, reptile, or fish must have been
"specially created." And this vast, this totally unprecedented change in
public opinion has been the result of the work of one man, and was
brought about in the short space of twenty years! This is the answer to
those who continue to maintain that the "origin of species" is not yet
discovered; that there are still doubts and difficulties; that there are

divergencies of structure so great that we cannot understand how they
had their beginning. We may admit all this, just as we may admit that
there are enormous difficulties in the way of a complete comprehension
of the origin and nature of all the parts of the solar system and of the
stellar universe. But we claim for Darwin that he is the Newton of
natural history, and that, just so surely as that the discovery and
demonstration by Newton of the law of gravitation established order in
place of chaos and laid a sure foundation for all future study of the
starry heavens, so surely has Darwin, by his discovery of the law of
natural selection and his demonstration of the great principle of the
preservation of useful variations in the struggle for life, not only thrown
a flood of light on the process of development of the whole organic
world, but also established a firm foundation for all future study of
nature.
In order to show the view Darwin took of his own work, and what it
was that he alone claimed to have done, the concluding passage of the
introduction to the Origin of Species should be carefully considered. It
is as follows: "Although much remains obscure, and will long remain
obscure, I can entertain no doubt, after the most deliberate and
dispassionate judgment of which I am capable, that the view which
most naturalists until recently entertained and which I formerly
entertained--namely, that each species has been independently
created--is erroneous. I am fully convinced that species are not
immutable; but that those belonging to what are called the same genera
are lineal descendants of some other and generally extinct species, in
the same manner as the acknowledged varieties of any one species are
the descendants of that species. Furthermore, I am convinced that
Natural Selection has been the most important, but not the exclusive,
means of modification."
It should be especially noted that all which is here claimed is now
almost universally admitted, while the criticisms of Darwin's works
refer almost exclusively to those numerous questions which, as he
himself says, "will long remain obscure."
The Darwinian Theory.

As it will be necessary, in the following chapters, to set forth a
considerable body of facts in almost every department of natural
history, in order to establish the fundamental propositions on which the
theory of natural selection rests, I propose to give a preliminary
statement of what the theory really is, in order that the reader may
better appreciate the necessity for discussing so many details, and may
thus feel a more enlightened interest in them. Many of the facts to be
adduced are so novel and so curious