amply avenged. Extinguished theologians lie about the cradle of every
science as the strangled snakes beside that of Hercules; and history
records that whenever science and orthodoxy have been fairly opposed,
the latter has been forced to retire from the lists, bleeding and
crushed, if not annihilated; scotched, if not slain. But orthodoxy is
the Bourbon of the world of thought. It learns not, neither can it
forget; and though, at present, bewildered and afraid to move, it is as
willing as ever to insist that the first chapter of Genesis contains the
beginning and the end of sound science; and to visit, with such petty
thunderbolts as its half-paralysed hands can hurl, those who refuse to
degrade Nature to the level of primitive Judaism.
Philosophers, on the other hand, have no such aggressive tendencies.
With eyes fixed on the noble goal to which "per aspera et ardua" they
tend, they may, now and then, be stirred to momentary wrath by the
unnecessary obstacles with which the ignorant, or the malicious,
encumber, if they cannot bar, the difficult path; but why should their
souls be deeply vexed? The majesty of Fact is on their side, and the
elemental forces of Nature are working for them. Not a star comes to the
meridian at its calculated time but testifies to the justice of their
methods--their beliefs are "one with the falling rain and with the
growing corn." By doubt they are established, and open inquiry is their
bosom friend. Such men have no fear of traditions however venerable, and
no respect for them when they become mischievous and obstructive; but
they have better than mere antiquarian business in hand, and if dogmas,
which ought to be fossil but are not, are not forced upon their notice,
they are too happy to treat them as non-existent.
The hypotheses respecting the origin of species which profess to stand
upon a scientific basis, and, as such, alone demand serious attention,
are of two kinds. The one, the "special creation" hypothesis, presumes
every species to have originated from one or more stocks, these not
being the result of the modification of any other form of living
matter--or arising by natural agencies--but being produced, as such, by
a supernatural creative act.
The other, the so-called "transmutation" hypothesis, considers that all
existing species are the result of the modification of pre-existing
species, and those of their predecessors, by agencies similar to those
which at the present day produce varieties and races, and therefore in
an altogether natural way; and it is a probable, though not a necessary
consequence of this hypothesis, that all living beings have arisen from
a single stock. With respect to the origin of this primitive stock, or
stocks, the doctrine of the origin of species is obviously not
necessarily concerned. The transmutation hypothesis, for example, is
perfectly consistent either with the conception of a special creation of
the primitive germ, or with the supposition of its having arisen, as a
modification of inorganic matter, by natural causes.
The doctrine of special creation owes its existence very largely to the
supposed necessity of making science accord with the Hebrew cosmogony;
but it is curious to observe that, as the doctrine is at present
maintained by men of science, it is as hopelessly inconsistent with the
Hebrew view as any other hypothesis.
If there be any result which has come more clearly out of geological
investigation than another, it is, that the vast series of extinct
animals and plants is not divisible, as it was once supposed to be, into
distinct groups, separated by sharply marked boundaries. There are no
great gulfs between epochs and formations--no successive periods marked
by the appearance of plants, of water animals, and of land animals, _en
masse_. Every year adds to the list of links between what the older
geologists supposed to be widely separated epochs: witness the crags
linking the drift with the older tertiaries; the Maestricht beds linking
the tertiaries with the chalk; the St. Cassian beds exhibiting an
abundant fauna of mixed mesozoic and palæozoic types, in rocks of an
epoch once supposed to be eminently poor in life; witness, lastly, the
incessant disputes as to whether a given stratum shall be reckoned
devonian or carboniferous, silurian or devonian, cambrian or silurian.
This truth is further illustrated in a most interesting manner by the
impartial and highly competent testimony of M. Pictet, from whose
calculations of what percentage of the genera of animals, existing in
any formation, lived during the preceding formation, it results that in
no case is the proportion less than _one-third_, or 33 per cent. It is
the triassic formation, or the commencement of the mesozoic epoch, which
has received this smallest inheritance from preceding ages. The other
formations not uncommonly exhibit 60, 80, or even 94 per cent. of genera
in common with those whose remains are imbedded in their predecessor.
Not only is this true, but the subdivisions of each formation exhibit
new species characteristic of, and found only in, them; and, in many
cases, as in the lias for example, the separate beds of these
subdivisions are distinguished by well-marked and peculiar forms of
life. A section, a hundred feet thick, will exhibit, at different
heights, a dozen species of ammonite, none of which passes beyond its
particular zone of limestone, or clay, into the zone below it or into
that above it; so that those who adopt the doctrine of special creation
must be prepared to admit that at intervals of time, corresponding with
the thickness of these beds, the Creator thought fit to interfere with
the natural course of events for the purpose of making a new ammonite.
It is not easy to transplant oneself into the frame of mind of those who
can accept such a conclusion as this, on any evidence short of absolute
demonstration; and it is difficult to see what is to be gained by so
doing, since, as we have said, it is obvious that such a view of the
origin of living beings is utterly opposed to the Hebrew cosmogony.
Deserving no aid from the powerful arm of bibliolatry, then, does the
received form of the hypothesis of special creation derive any support
from science or sound logic? Assuredly not much. The arguments brought
forward in its favour all take one form: If species were not
supernaturally created, we cannot understand the facts _x_, or _y_, or
_z_; we cannot understand the structure of animals or plants, unless we
suppose they were contrived for special ends; we cannot understand the
structure of the eye, except by supposing it to have been made to see
with; we cannot understand instincts, unless we suppose animals to have
been miraculously endowed with them.
As a question of dialectics, it must be admitted that this sort of
reasoning is not very formidable to those who are not to be frightened
by consequences. It is an _argumentum ad ignorantiam_--take this
explanation or be ignorant. But suppose we prefer to admit our ignorance
rather than adopt a hypothesis at variance with all the teachings of
Nature? Or, suppose for a moment we admit the explanation, and then
seriously ask ourselves how much the wiser are we; what does the
explanation explain? Is it any more than a grandiloquent way of
announcing the fact, that we really know nothing about the matter? A
phenomenon is explained when it is shown to be a case of some general
law of Nature; but the supernatural interposition of the Creator can, by
the nature of the case, exemplify no law, and if species have really
arisen in this way, it is absurd to attempt to discuss their origin.
Or, lastly, let us ask ourselves whether any amount of evidence which
the nature of our faculties permits us to attain, can justify us in
asserting that any phænomenon is out of the reach of natural causation.
To this end it is obviously necessary that we should know all the
consequences to which all possible combinations, continued through
unlimited time, can give rise. If we knew these, and found none
competent to originate species, we should have good ground for denying
their origin by natural causation. Till we know them, any hypothesis is
better than one which involves us in such miserable presumption.
But the hypothesis of special creation is not only a mere specious mask
for our ignorance; its existence in Biology marks the youth and
imperfection of the science. For what is the history of every science
but the history of the elimination of the notion of creative, or other
interferences, with the natural order of the phænomena which are the
subject-matter of that science? When Astronomy was young "the morning
stars sang together for joy," and the planets were guided in their
courses by celestial hands. Now, the harmony of the stars has resolved
itself into gravitation according to the inverse squares of the
distances, and the orbits of the planets are deducible from the laws of
the forces which allow a schoolboy's stone to break a window. The
lightning was the angel of the Lord; but it has pleased Providence, in
these modern times, that science should make it the humble messenger of
man, and we know that every flash that shimmers about the horizon on a
summer's evening is determined by ascertainable conditions, and that its
direction and brightness might, if our knowledge of these were great
enough, have been calculated.
The solvency of great mercantile companies rests on the validity of the
laws which have been ascertained to govern the seeming irregularity of
that human life which the moralist bewails as the most uncertain of
things; plague, pestilence, and famine are admitted, by all but fools,
to be the natural result of causes for the most part fully within human
control, and not the unavoidable tortures inflicted by wrathful
Omnipotence upon his helpless handiwork.
Harmonious order governing eternally continuous progress--the web and
woof of matter and force interweaving by slow degrees, without a broken
thread, that veil which lies between us and the Infinite--that universe
which alone we know or can know; such is the picture which science draws
of the world, and in proportion as any part of that picture is in unison
with the rest, so may we feel sure that it is rightly painted. Shall
Biology alone remain out of harmony with her sister sciences?
Such arguments against the hypothesis of the direct creation of species
as these are plainly enough deducible from general considerations; but
there are, in addition, phænomena exhibited by species themselves, and
yet not so much a part of their very essence as to have required earlier
mention, which are in the highest degree perplexing, if we adopt the
popularly accepted hypothesis. Such are the facts of distribution in
space and in time; the singular phænomena brought to light by the study
of development; the structural relations of species upon which our
systems of classification are founded; the great doctrines of
philosophical anatomy, such as that of homology, or of the community of
structural plan exhibited by large groups of species differing very
widely in their habits and functions.
The species of animals which inhabit the sea on opposite sides of the
isthmus of Panama are wholly distinct;[63] the animals and plants which
inhabit islands are commonly distinct from those of the neighbouring
mainlands, and yet have a similarity of aspect. The mammals of the
latest tertiary epoch in the Old and New Worlds belong to the same
genera, or family groups, as those which now inhabit the same great
geographical area. The crocodilian reptiles which existed in the
earliest secondary epoch were similar in general structure to those now
living, but exhibit slight differences in their vertebræ, nasal
passages, and one or two other points. The guinea-pig has teeth which
are shed before it is born, and hence can never subserve the masticatory
purpose for which they seem contrived, and, in like manner, the female
dugong has tusks which never cut the gum. All the members of the same
great group run through similar conditions in their development, and all
their parts, in the adult state, are arranged according to the same
plan. Man is more like a gorilla than a gorilla is like a lemur. Such
are a few, taken at random, among the multitudes of similar facts which
modern research has established; but when the student seeks for an
explanation of them from the supporters of the received hypothesis of
the origin of species, the reply he receives is, in substance, of
Oriental simplicity and brevity--"Mashallah! it so pleases God!" There
are different species on opposite sides of the isthmus of Panama,
because they were created different on the two sides. The pliocene
mammals are like the existing ones, because such was the plan of
creation; and we find rudimental organs and similarity of plan, because
it has pleased the Creator to set before himself a "divine exemplar or
archetype," and to copy it in his works; and somewhat ill, those who
hold this view imply, in some of them. That such verbal hocus-pocus
should be received as science will one day be regarded as evidence of
the low state of intelligence in the nineteenth century, just as we
amuse ourselves with the phraseology about Nature's abhorrence of a
vacuum, wherewith Torricelli's compatriots were satisfied to explain the
rise of water in a pump. And be it recollected that this sort of
satisfaction works not only negative but positive ill, by discouraging
inquiry, and so depriving man of the usufruct of one of the most fertile
fields of his great patrimony, Nature.
The objections to the doctrine of the origin of species by special
creation which have been detailed, must have occurred, with more or less
force, to the mind of every one who has seriously and independently
considered the subject. It is therefore no wonder that, from time to
time, this hypothesis should have been met by counter hypotheses, all as
well, and some better, founded than itself; and it is curious to remark
that the inventors of the opposing views seem to have been led into them
as much by their knowledge of geology, as by their acquaintance with
biology. In fact, when the mind has once admitted the conception of the
gradual production of the present physical state of our globe, by
natural causes operating through long ages of time, it will be little
disposed to allow that living beings have made their appearance in
another way, and the speculations of De Maillet and his successors are
the natural complement of Scilla's demonstration of the true nature of
fossils.
A contemporary of Newton and of Leibnitz, sharing therefore in the
intellectual activity of the remarkable age which witnessed the birth of
modern physical science, Benoît de Maillet spent a long life as a
consular agent of the French Government in various Mediterranean ports.
For sixteen years, in fact, he held the office of Consul-General in
Egypt, and the wonderful phænomena offered by the valley of the Nile
appear to have strongly impressed his mind, to have directed his
attention to all facts of a similar order which came within his
observation, and to have led him to speculate on the origin of the
present condition of our globe and of its inhabitants. But, with all his
ardour for science, De Maillet seems to have hesitated to publish views
which, notwithstanding the ingenious attempts to reconcile them with the
Hebrew hypothesis contained in the preface to "Telliamed," were hardly
likely to be received with favour by his contemporaries.
But a short time had elapsed since more than one of the great anatomists
and physicists of the Italian school had paid dearly for their
endeavours to dissipate some of the prevalent errors; and their
illustrious pupil, Harvey, the founder of modern physiology, had not
fared so well, in a country less oppressed by the benumbing influences
of theology, as to tempt any man to follow his example. Probably not
uninfluenced by these considerations, his Catholic majesty's
Consul-General for Egypt kept his theories to himself throughout a long
life, for "Telliamed," the only scientific work which is known to have
proceeded from his pen, was not printed till 1735, when its author had
reached the ripe age of seventy-nine; and though De Maillet lived three
years longer, his book was not given to the world before 1748. Even then
it was anonymous to those who were not in the secret of the anagramatic
character of its title; and the preface and dedication are so worded as,
in case of necessity, to give the printer a fair chance of falling back
on the excuse that the work was intended for a mere _jeu d'esprit_.
The speculations of the supposititious Indian sage, though quite as
sound as those of many a "Mosaic Geology," which sells exceedingly well,
have no great value if we consider them by the light of modern science.
The waters are supposed to have originally covered the whole globe; to
have deposited the rocky masses which compose its mountains by processes
comparable to those which are now forming mud, sand, and shingle; and
then to have gradually lowered their level, leaving the spoils of their
animal and vegetable inhabitants embedded in the strata. As the dry land
appeared, certain of the aquatic animals are supposed to have taken to
it, and to have become gradually adapted to terrestrial and aërial modes
of existence. But if we regard the general tenor and style of the
reasoning in relation to the state of knowledge of the day, two
circumstances appear very well worthy of remark. The first, that De
Maillet had a notion of the modifiability of living forms (though
without any precise information on the subject), and how such
modifiability might account for the origin of species; the second, that
he very clearly apprehended the great modern geological doctrine, so
strongly insisted upon by Hutton, and so ably and comprehensively
expounded by Lyell, that we must look to existing causes for the
explanation of past geological events. Indeed, the following passage of
the preface, in which De Maillet is supposed to speak of the Indian
philosopher Telliamed, his _alter ego_, might have been written by the
most philosophical uniformitarian of the present day:--
"Ce qu'il y a d'étonnant, est que pour arriver à ces connoissances
il semble avoir perverti l'ordre naturel, pui-qu'au lieu de
s'attacher d'abord à rechercher l'origine de notre globe il a
commencé par travailler à s'instruire de la nature. Mais à
l'entendre, ce renversement de l'ordre a été pour lui l'effet d'un
génie favorable qui l'a conduit pas à pas et comme par la main aux
découvertes les plus sublimes. C'est en décomposant la substance de
ce globe par une anatomie exacte de toutes ses parties qu'il a
premièrement appris de quelles matières il etait composé et quels
arrangemens ces mêmes matières observaient entre elles. Ces
lumières jointes à l'esprit de comparaison toujours nécessaire à
quiconque entreprend de percer les voiles dont la nature aime à se
cacher, ont servi de guide à notre philosophe pour parvenir à des
connoissances plus intéressantes. Par la matière et l'arrangement
de ces compositions il prétend avoir reconnu quelle est la
véritable origine de ce globe que nous habitons, comment et par qui
il a été formé."--Pp. xix. xx.
But De Maillet was before his age, and as could hardly fail to happen to
one who speculated on a zoological and botanical question before
Linnæus, and on a physiological problem before Haller, he fell into
great errors here and there; and hence, perhaps, the general neglect of
his work. Robinet's speculations are rather behind, than in advance of,
those of De Maillet; and though Linnæus may have played with the
hypothesis of transmutation, it obtained no serious support until
Lamarck adopted it, and advocated it with great ability in his
"Philosophie Zoologique."
Impelled towards the hypothesis of the transmutation of species, partly
by his general cosmological and geological views; partly by the
conception of a graduated, though irregularly branching, scale of being,
which had arisen out of his profound study of plants and of the lower
forms of animal life, Lamarck, whose general line of thought often
closely resembles that of De Maillet, made a great advance upon the
crude and merely speculative manner in which that writer deals with the
question of the origin of living beings, by endeavouring to find
physical causes competent to effect that change of one species into
another, which De Maillet had only supposed to occur. And Lamarck
conceived that he had found in Nature such causes, amply sufficient for
the purpose in view. It is a physiological fact, he says, that organs
are increased in size by action, atrophied by inaction; it is another
physiological fact that modifications produced are transmissible to
offspring. Change the actions of an animal, therefore, and you will
change its structure, by increasing the development of the parts newly
brought into use and by the diminution of those less used; but by
altering the circumstances which surround it you will alter its actions,
and hence, in the long run, change of circumstance must produce change
of organization. All the species of animals, therefore, are, in
Lamarck's view, the result of the indirect action of changes of
circumstance upon those primitive germs which he considered to have
originally arisen, by spontaneous generation, within the waters of the
globe. It is curious, however, that Lamarck should insist so
strongly[64] as he has done, that circumstances never in any degree
directly modify the form or the organization of animals, but only
operate by changing their wants and consequently their actions; for he
thereby brings upon himself the obvious question, how, then, do plants,
which cannot be said to have wants or actions, become modified? To this
he replies, that they are modified by the changes in their nutritive
processes, which are effected by changing circumstances; and it does not
seem to have occurred to him that such changes might be as well supposed
to take place among animals.
When we have said that Lamarck felt that mere speculation was not the
way to arrive at the origin of species, but that it was necessary, in
order to the establishment of any sound theory on the subject, to
discover by observation or otherwise, some _vera causa_, competent to
give rise to them; that he affirmed the true order of classification to
coincide with the order of their development one from another; that he
insisted on the necessity of allowing sufficient time, very strongly;
and that all the varieties of instinct and reason were traced back by
him to the same cause as that which has given rise to species, we have
enumerated his chief contributions to the advance of the question. On
the other hand, from his ignorance of any power in Nature competent to
modify the structure of animals, except the development of parts, or
atrophy of them, in consequence of a change of needs, Lamarck was led to
attach infinitely greater weight than it deserves to this agency, and
the absurdities into which he was led have met with deserved
condemnation. Of the struggle for existence, on which, as, we shall
see, Mr. Darwin lays such great stress, he had no conception; indeed, he
doubts whether there really are such things as extinct species, unless
they be such large animals as may have met their death at the hands of
man; and so little does he dream of there being any other destructive
causes at work, that, in discussing the possible existence of fossil
shells, he asks, "Pourquoi d'ailleurs seroient-ils perdues dès que
l'homme n'a pu opérer leur destruction?" (Phil. Zool., vol. i. p. 77.)
Of the influence of selection Lamarck has as little notion, and he makes
no use of the wonderful phænomena which are exhibited by domesticated
animals, and illustrate its powers. The vast influence of Cuvier was
employed against the Lamarckian views, and, as the untenability of some
of his conclusions was easily shown, his doctrines sank under the
opprobium of scientific, as well as of theological, heterodoxy. Nor have
the efforts made of late years to revive them tended to re-establish
their credit in the minds of sound thinkers acquainted with the facts of
the case; indeed it may be doubted whether Lamarck has not suffered more
from his friends than from his foes.