is of three kinds. First, he endeavours to prove that species may be
originated by selection; secondly, he attempts to show that natural
causes are competent to exert selection; and thirdly, he tries to prove
that the most remarkable and apparently anomalous phenomena exhibited by
the distribution, development, and mutual relations of species, can be
shown to be deducible from the general doctrine of their origin, which
he propounds, combined with the known facts of geological change; and
that, even if all these phenomena are not at present explicable by it,
none are necessarily inconsistent with it.
There cannot be a doubt that the method of inquiry which Mr. Darwin
has adopted is not only rigorously in accordance with the canons of
scientific logic, but that it is the only adequate method. Critics
exclusively trained in classics or in mathematics, who have never
determined a scientific fact in their lives by induction from experiment
or observation, prate learnedly about Mr. Darwin's method, which is not
inductive enough, not Baconian enough, forsooth, for them. But even if
practical acquaintance with the process of scientific investigation
is denied them, they may learn, by the perusal of Mr. Mill's admirable
chapter "On the Deductive Method," that there are multitudes of
scientific inquiries in which the method of pure induction helps the
investigator but a very little way.
"The mode of investigation," says Mr. Mill, "which, from the proved
inapplicability of direct methods of observation and experiment, remains
to us as the main source of the knowledge we possess, or can acquire,
respecting the conditions and laws of recurrence of the more complex
phenomena, is called, in its most general expression, the deductive
method, and consists of three operations: the first, one of
direct induction; the second, of ratiocination; and the third, of
verification."
Now, the conditions which have determined the existence of species are
not only exceedingly complex, but, so far as the great majority of
them are concerned, are necessarily beyond our cognizance. But what Mr.
Darwin has attempted to do is in exact accordance with the rule laid
down by Mr. Mill; he has endeavoured to determine certain great facts
inductively, by observation and experiment; he has then reasoned from
the data thus furnished; and lastly, he has tested the validity of his
ratiocination by comparing his deductions with the observed facts of
Nature. Inductively, Mr. Darwin endeavours to prove that species arise
in a given way. Deductively, he desires to show that, if they arise in
that way, the facts of distribution, development, classification, etc.,
may be accounted for, 'i.e.' may be deduced from their mode of origin,
combined with admitted changes in physical geography and climate, during
an indefinite period. And this explanation, or coincidence of observed
with deduced facts, is, so far as it extends, a verification of the
Darwinian view.
There is no fault to be found with Mr. Darwin's method, then; but it is
another question whether he has fulfilled all the conditions imposed by
that method. Is it satisfactorily proved, in fact, that species may
be originated by selection? that there is such a thing as natural
selection? that none of the phenomena exhibited by species are
inconsistent with the origin of species in this way? If these questions
can be answered in the affirmative, Mr. Darwin's view steps out of the
rank of hypotheses into those of proved theories; but, so long as the
evidence at present adduced falls short of enforcing that affirmation,
so long, to our minds, must the new doctrine be content to remain among
the former--an extremely valuable, and in the highest degree probable,
doctrine, indeed the only extant hypothesis which is worth anything in a
scientific point of view; but still a hypothesis, and not yet the theory
of species.
After much consideration, and with assuredly no bias against Mr.
Darwin's views, it is our clear conviction that, as the evidence stands,
it is not absolutely proven that a group of animals, having all the
characters exhibited by species in Nature, has ever been originate
by selection, whether artificial or natural. Groups having the
morphological character of species, distinct and permanent races
in fact, have been so produced over and over again; but there is
no positive evidence, at present, that any group of animals has, by
variation and selective breeding, given rise to another group which
was, even in the least degree, infertile with the first. Mr. Darwin is
perfectly aware of this weak point, and brings forward a multitude
of ingenious and important arguments to diminish the force of the
objection. We admit the value of these arguments to their fullest
extent; nay, we will go so far as to express our belief that
experiments, conducted by a skilful physiologist, would very probably
obtain the desired production of mutually more or less infertile breeds
from a common stock, in a comparatively few years; but still, as the
case stands at present, this "little rift within the lute" is not to be
disguised nor overlooked.
In the remainder of Mr. Darwin's argument our own private ingenuity
has not hitherto enabled us to pick holes of any great importance; and
judging by what we hear and read, other adventurers in the same field
do not seem to have been much more fortunate. It has been urged, for
instance, that in his chapters on the struggle for existence and on
natural selection, Mr. Darwin does not so much prove that natural
selection does occur, as that it must occur; but, in fact, no other sort
of demonstration is attainable. A race does not attract our attention
in Nature until it has, in all probability, existed for a considerable
time, and then it is too late to inquire into the conditions of its
origin. Again, it is said that there is no real analogy between the
selection which takes place under domestication, by human influence,
and any operation which can be effected by Nature, for man interferes
intelligently. Reduced to its elements, this argument implies that an
effect produced with trouble by an intelligent agent must, 'a fortiori',
be more troublesome, if not impossible, to an unintelligent agent. Even
putting aside the question whether Nature, acting as she does according
to definite and invariable laws, can be rightly called an unintelligent
agent, such a position as this is wholly untenable. Mix salt and sand,
and it shall puzzle the wisest of men, with his mere natural appliances,
to separate all the grains of sand from all the grains of salt; but a
shower of rain will effect the same object in ten minutes. And so, while
man may find it tax all his intelligence to separate any variety which
arises, and to breed selectively from it, the destructive agencies
incessantly at work in Nature, if they find one variety to be more
soluble in circumstances than the other, will inevitably, in the long
run, eliminate it.
A frequent and a just objection to the Lamarckian hypothesis of the
transmutation of species is based upon the absence of transitional forms
between many species. But against the Darwinian hypothesis this argument
has no force. Indeed, one of the most valuable and suggestive parts of
Mr. Darwin's work is that in which he proves, that the frequent absence
of transitions is a necessary consequence of his doctrine, and that
the stock whence two or more species have sprung, need in no respect be
intermediate between these species. If any two species have arisen from
a common stock in the same way as the carrier and the pouter, say, have
arisen from the rock-pigeon, then the common stock of these two species
need be no more intermediate between the two than the rock-pigeon is
between the carrier and pouter. Clearly appreciate the force of
this analogy, and all the arguments against the origin of species by
selection, based on the absence of transitional forms, fall to the
ground. And Mr. Darwin's position might, we think, have been even
stronger than it is if he had not embarrassed himself with the aphorism,
"Natura non facit saltum," which turns up so often in his pages. We
believe, as we have said above, that Nature does make jumps now and
then, and a recognition of the fact is of no small importance in
disposing of many minor objections to the doctrine of transmutation.
But we must pause. The discussion of Mr. Darwin's arguments in detail
would lead us far beyond the limits within which we proposed, at
starting, to confine this article. Our object has been attained if we
have given an intelligible, however brief, account of the established
facts connected with species, and of the relation of the explanation of
those facts offered by Mr. Darwin to the theoretical views held by his
predecessors and his contemporaries, and, above all, to the requirements
of scientific logic. We have ventured to point out that it does not, as
yet, satisfy all those requirements; but we do not hesitate to assert
that it is as superior to any preceding or contemporary hypothesis, in
the extent of observational and experimental basis on which it rests,
in its rigorously scientific method, and in its power of explaining
biological phenomena, as was the hypothesis of Copernicus to the
speculations of Ptolemy. But the planetary orbits turned out to be
not quite circular after all, and, grand as was the service Copernicus
rendered to science, Kepler and Newton had to come after him. What if
the orbit of Darwinism should be a little too circular? What if species
should offer residual phenomena, here and there, not explicable by
natural selection? Twenty years hence naturalists may be in a position
to say whether this is, or is not, the case; but in either event they
will owe the author of 'The Origin of Species' an immense debt of
gratitude. We should leave a very wrong impression on the reader's
mind if we permitted him to suppose that the value of that work depends
wholly on the ultimate justification of the theoretical views which it
contains. On the contrary, if they were disproved to-morrow, the book
would still be the best of its kind--the most compendious statement
of well-sifted facts bearing on the doctrine of species that has ever
appeared. The chapters on Variation, on the Struggle for Existence, on
Instinct, on Hybridism, on the Imperfection of the Geological Record, on
Geographical Distribution, have not only no equals, but, so far as
our knowledge goes, no competitors, within the range of biological
literature. And viewed as a whole, we do not believe that, since the
publication of Von Baer's Researches on Development, thirty years ago,
any work has appeared calculated to exert so large an influence, not
only on the future of Biology, but in extending the domination of
Science over regions of thought into which she has, as yet, hardly
penetrated.
[Footnote 1: 'The Westminster Review', April 1860.]
[Footnote 2: On the Osteology of the Chimpanzees and Orangs:
Transactions of the Zoological Society, 1858.]
[Footnote 3: Colonel Humphreys' statements are exceedingly explicit
on this point:--"When an Ancon ewe is impregnated by a common ram, the
increase resembles wholly either the ewe or the ram. The increase of the
common ewe impregnated by an Ancon ram follows entirely the one or
the other, without blending any of the distinguishing and essential
peculiarities of both. Frequent instances have happened where common
ewes have had twins by Ancon rams, when one exhibited the complete marks
and features of the ewe, the other of the ram. The contrast has been
rendered singularly striking, when one short-legged and one long-legged
lamb, produced at a birth, have been seen sucking the dam at the same
time."--'Philosophical Transactions', 1813, Pt. I. pp. 89, 90.]
[Footnote 4: Recent investigations tend to show that this statement is
not strictly accurate.--1870.]
[Footnote 5: See 'Phil. Zoologique,' vol. i. p. 222, 'et seq.']
End of Project Gutenberg's The Origin of Species, by Thomas H. Huxley