THE DARWINIAN REVOLUTION BEGINS.
So far as the scientific world was concerned the 'Origin of Species'
fell, like a grain of mustard seed, upon good and well-prepared ground;
the plant that sprang from it grew up forthwith into a great and stately
tree, that overshadowed with its spreading branches all the corners of
the earth.
The soil, indeed, had been carefully broken for it beforehand: Lamarck
and St. Hilaire, Spencer and Chambers, had ploughed and harrowed in all
diligence; and the minds of men were thoroughly ready for the
assimilation of the new doctrine. But the seed itself, too, was the
right germ for the exact moment; it contained within itself the
vivifying principle that enabled it to grow and wax exceeding great
where kindred germs before had withered away, or had borne but scanty
and immature fruit.
Two conditions contributed to this result, one external, the other
internal.
First for the less important external consideration. Darwin himself was
a sound man with an established reputation for solidity and learning.
That gained for his theory from the very first outset universal respect
and a fair hearing. Herbert Spencer was known to be a philosopher: and
the practical English nation mistrusts philosophers: those people probe
too deep and soar too high for any sensible person to follow them in all
their flights. Robert Chambers, the unknown author of 'Vestiges of
Creation,' was a shallow sciolist; it was whispered abroad that he was
even inaccurate and slovenly in his facts: and your scientific plodder
detests the very shadow of minute inaccuracy, though it speak with the
tongues of men and angels, and be bound up with all the grasp and power
of a Newton or a Goethe. But Charles Darwin was a known personage, an
F.R.S., a distinguished authority upon coral reefs and barnacles, a
great geologist, a great biologist, a great observer and indefatigable
collector. His book came into the public hands stamped with the
imprimatur of official recognition. Darwin was the father of the infant
theory; Lyell and Hooker stood for its sponsors. The world could not
afford to despise its contents; they could not brand its author offhand
as a clever dreamer or a foolish amateur, or consign him to the dreaded
English limbo of the 'mere theorist.'
Next, for the other and far more important internal consideration. The
book itself was one of the greatest, the most learned, the most lucid,
the most logical, the most crushing, the most conclusive, that the world
had ever yet seen. Step by step, and principle by principle, it proved
every point in its progress triumphantly before it went on to
demonstrate the next. So vast an array of facts so thoroughly in hand
had never before been mustered and marshalled in favour of any
biological theory. Those who had insight to learn and understand were
convinced at once by the cogency of the argument; those who had not were
overpowered and silenced by the weight of the authority and the mass of
the learning. A hot battle burst forth at once, no doubt, around the
successful volume; but it was one of those battles which are aroused
only by great truths,--a battle in which the victory is a foregone
conclusion, and the rancour of the assailants the highest compliment to
the prowess of the assailed.
Darwin himself, in his quiet country home at Down, was simply astonished
at the rapid success of his own work. The first edition was published at
the end of November 1859; it was exhausted almost immediately, and a
second was got ready in hot haste by the beginning of January 1860. In
less than six weeks the book had become famous, and Darwin found himself
the centre of a European contest, waged with exceeding bitterness, over
the truth or falsity of his wonderful volume. To the world at large
Darwinism and evolution became at once synonymous terms. The same people
who would entirely ascribe the Protestant Reformation to the account of
Luther, and the inductive philosophy to the account of Bacon, also
believed, in the simplicity of their hearts, that the whole vast
evolutionary movement was due at bottom to that very insidious and
dangerous book of Mr. Darwin's.
The fact is, profound as had been the impulses in the evolutionary
direction among men of science before Darwin's work appeared at all,
immense as were the throes and pangs of labour throughout all Europe
which preceded and accompanied its actual birth, when it came at last it
came to the general world of unscientific readers with all the sudden
vividness and novelty of a tremendous earthquake. Long predestined, it
was yet wholly unexpected. Men at large had known nothing or next to
nothing of this colossal but hidden revolutionary force which had been
gathering head and energy for so many years unseen within the bowels of
the earth; and now that its outer manifestation had actually burst upon
them, they felt the solid ground of dogmatic security bodily giving way
beneath their feet, and knew not where to turn in their extremity for
support. Naturally, it was the theological interest that felt itself at
first most forcibly assailed. The first few chapters of Genesis, or
rather the belief in their scientific and historical character, already
sapped by the revelations of geology, seemed to orthodox defenders to be
fatally undermined if the Darwinian hypothesis were once to meet with
general recognition. The first resource of menaced orthodoxy is always
to deny the alleged facts; the second is to patch up tardily the feeble
and hollow _modus vivendi_ of an artificial pact. On this occasion the
orthodox acted strictly after their kind: but to their credit it should
be added that they yielded gracefully in the long run to the unanimous
voice of scientific opinion. Twenty-three years later, when all that was
mortal of Charles Darwin was being borne with pomp and pageantry to its
last resting-place in Westminster Abbey, enlightened orthodoxy, with
generous oblivion, ratified a truce over the dead body of the great
leader, and, outgrowing its original dread of naturalistic
interpretations, accepted his theory without reserve as 'not necessarily
hostile to the main fundamental truths of religion.' Let us render
justice to the vanquished in a memorable struggle. Churchmen followed
respectfully to the grave with frank and noble inconsistency the
honoured remains of the very teacher whom less than a quarter of a
century earlier they had naturally dreaded as loosening the traditional
foundations of all accepted religion and morality.
But if the attack was fierce and bitter, the defence was assisted by a
sudden access of powerful forces from friendly quarters. A few of the
elder generation of naturalists held out, indeed, for various shorter or
longer periods; some of them never came into the camp at all, but
lingered on, left behind, like stragglers from the onward march, by the
younger biologists, in isolated non-conformity on the lonely heights of
austere officialism. Their business was to ticket and docket and
pigeon-hole, not to venture abroad on untried wings into the airy
regions of philosophical speculation. The elder men, in fact, had many
of them lost that elasticity and modifiability of intellect which is
necessary for the reception of new and revolutionary fundamental
concepts. A mind that has hardened down into the last stage of extreme
maturity may assimilate fresh facts and fresh minor principles, but it
cannot assimilate fresh synthetic systems of the entire cosmos.
Moreover, some of the elder thinkers were committed beforehand to
opposing views, with which they lacked either the courage or the
intellectual power to break; while others were entangled by religious
restrictions, and unable to free themselves from the cramping fetters of
a narrow orthodoxy. But even among his own contemporaries and seniors
Darwin found not a few whose minds were thoroughly prepared beforehand
for the reception of his lucid and luminous hypothesis; while the
younger naturalists, with the plasticity of youth, assimilated almost
to a man, with the utmost avidity, the great truths thus showered down
upon them by the preacher of evolution.
Sir Joseph Hooker and Professor Huxley were among the first to give in
their adhesion and stand up boldly for the new truth by the side of the
reckless and disturbing innovator. In June 1859, nearly a year after the
reading of the Darwin-Wallace papers at the Linnean Society, but five
months previously to the publication of the 'Origin of Species,' Huxley
lectured at the Royal Institution on 'Persistent Types of Animal Life,'
and declared against the old barren theory of successive creations, in
favour of the new and fruitful hypothesis of gradual modification. In
December 1859, a month later than the appearance of Darwin's book,
Hooker published his 'Introduction to the Flora of Australia,' in the
first part of which he championed the belief in the descent and
modification of species, and enforced his views by many original
observations drawn from the domain of botanical science. For fifteen
years, as Darwin himself gratefully observed in his introduction to the
'Origin of Species,' that learned botanist had shared the secret of
natural selection, and aided its author in every possible way by his
large stores of knowledge and his excellent judgment. Bates, the
naturalist on the Amazons, followed fast with his beautiful and striking
theory of mimicry, a crucial instance well explained. The facts of the
strange disguises which birds and insects often assume had long been
present to his acute mind, and he hailed with delight the discovery of
the new principle, which at once enabled him to reduce them with ease
to symmetry and order. To Herbert Spencer, an evolutionist in fibre from
the very beginning, the fresh doctrine of natural selection came like a
powerful ally and an unexpected assistant in deciphering the deep
fundamental problems on which he was at that moment actually engaged;
and in his 'Principles of Biology,' even then in contemplation, he at
once adopted and utilised the new truth with all the keen and vigorous
insight of his profound analytic and synthetic intellect. The first part
of that important work was issued to subscribers just three years after
the original appearance of the 'Origin of Species;' the first volume was
fully completed in October 1864. It is to Mr. Spencer that we owe the
pellucid expression 'survival of the fittest,' which conveys even better
than Darwin's own phrase, 'natural selection,' the essential element
added by the 'Origin of Species' to the pre-existing evolutionary
conception.
The British Association for the Advancement of Science held its big
annual doctrinaire picnic the next summer after the publication of
Darwin's book, at Oxford. The Oxford meeting was a stormy and a
well-remembered one. The 'Origin of Species' was there discussed and
attacked before a biological section strangely enough presided over by
Darwin's old Cambridge teacher, Professor Henslow. Though then a
beneficed parish priest, Henslow had the boldness frankly to avow his
own acceptance of his great pupil's startling conclusions. Huxley
followed in the same path, as did also Lubbock and Hooker. On the whole,
the evolutionists were already in the ascendant; the fresh young
intellects especially being quick to seize upon the new pabulum so
generously dealt out to them by the new evolutionism.
Among scientific minds of the first order, Lyell alone in England,
heavily weighted by theological preconceptions, for awhile hung back.
All his life long, as his letters show us, the great geologist had felt
the powerful spell of the Lamarckian hypothesis continually enticing him
with its seductive charm. He had fought against it blindly, in the
passionate endeavour to preserve what he thought his higher faith in the
separate and divine creation of man; but ever and anon he returned anew
to the biological Circe with a fresh fascination, as the moth returns to
the beautiful flame that has scorched and singed it. In a well-known
passage in the earlier editions of his 'Principles of Geology,' the
father of uniformitarianism gives at length his own reasons for
dissenting from the doctrine of evolution as then set forth; and even
after Darwin's discovery had supplied him with a new clue, a _vera
causa_, a sufficient power for the modification of species into fresh
forms, theological difficulties made him cling still as long as possible
to the old theory of the origin of man which he loved to describe as
that of the 'archangel ruined.' He was loth to exchange this cherished
belief for the degrading alternative (as it approved itself to him) of
the ape elevated. But in the end, with the fearless honesty of a
searcher after truth, he gave way slowly and regretfully. Always looking
back with something like remorse to the flesh-pots of the ecclesiastical
Egypt, with its enticing visions of fallen grandeur, the great thinker
whose uniformitarian theory of geology had more than aught else paved
the way for the gradual acceptance of Darwin's evolutionism, came out
at last from the house of bondage, and nobly ranged himself on the side
of what his intellect judged to be the truth of nature, though his
emotions urged him hard to blind his judgment and to neglect its lights
for an emotional figment. Science has no more pathetic figure than that
of the old philosopher, in his sixty-sixth year, throwing himself with
all the eagerness of youth into what he had long considered the wrong
scale, and vigorously wrecking in the 'Antiquity of Man' what seemed to
the dimmed vision of his own emotional nature the very foundations of
his beloved creed. But still he did it. He came out and was separate. In
his own idiomatic language, he found at last that 'we must go the whole
ourang;' and, deep as was the pang that the recantation cost him, he
formally retracted the condemnation of 'transformism' in his earlier
works, and accepted, however unwillingly, the theory he had so often and
so deliberately rejected.
The 'Antiquity of Man' came out in February 1863, some three years after
the 'Origin of Species.' For some time speculation had been active over
the strange hatchets which Boucher de Perthes had recently unearthed
among the Abbeville drift--shapeless masses of chipped flint rudely
fashioned into the form of an axe, which we now call palæolithic
implements, and know to be the handicraft of preglacial men. But until
Lyell's authoritative work appeared the unscientific public could not
tell exactly what to think of these curious and almost unhuman-looking
objects. Lyell at once set all doubts at rest; the magic of his name
silenced the derisive whispers of the dissidents. Already, in the
previous year, the first fasciculus of Colenso's famous work on the
Pentateuch had dealt a serious blow from the ecclesiastical and critical
side at the authenticity and historical truth of the Mosaic cosmogony.
Lyell now from the scientific side completely demolished its literal
truth, as ordinarily interpreted, by throwing back the primitive origin
of our race into a dim past of immeasurable antiquity. In so doing he
was clearing the way for Charles Darwin's second great work, 'The
Descent of Man;' and by incorporating in his book Huxley's remarks on
the Neanderthal skull, and much similar evolutionary matter, he
advertised the new creed in the animal origin of our race with all the
acquired weight of his immense and justly-deserved European reputation.
As a matter of taste, Lyell did not relish the application of
evolutionism to his own species. But, with that perfect loyalty to fact
which he shared so completely with Charles Darwin, as soon as he found
the evidence overwhelming, he gave in. By that grudging concession he
immensely strengthened the position of the new creed. 'I plead guilty,'
he writes to Sir Joseph Hooker, 'to going farther in my reasoning
towards transmutation than in my sentiments and imagination, and perhaps
for that very reason I shall lead more people on to Darwin and you, than
one who, being born later, like Lubbock, has comparatively little to
abandon of old and long-cherished ideas, which constituted the charm to
me of the theoretical part of the science in my earlier days.' And to
Darwin himself he writes regretfully. 'The descent of man from the
brutes takes away much of the charm from my speculations on the past
relating to such matters.' This very reluctance itself told powerfully
in favour of Charles Darwin's novel theories: there is no evidence more
valuable to a cause than that which it extorts by moral force, in spite
of himself, from the faltering lips of an unwilling witness.
The same year that saw the publication of Lyell's 'Antiquity of Man' saw
also the first appearance of Huxley's work on 'Man's Place in Nature.'
Darwin himself had been anxious rather than otherwise to avoid too close
reference to the implications of his theory as regards the origin and
destiny of the human race. He had desired that his strictly scientific
views on the rise of specific distinctions should be judged entirely on
their own merits, unhampered by the interference of real or supposed
theological and ethical considerations. His own language on all such
subjects, wherever he was compelled to trench on them in the 'Origin of
Species,' was guarded and conciliatory; he scarcely referred at all to
man or his history; and his occasional notices of the moving principle
and first cause of the entire cosmos were reverential and religious in
the truest sense and in the highest degree. But you cannot let loose a
moral whirlwind, and then attempt to direct its course; you cannot open
the floodgates of opinion or of speculation, and then pretend to set
limits to the scope of their restless motion. Darwin soon found out that
people would insist in drawing inferences beyond what was written, and
in seeing implicit conclusions when they were not definitely formulated
in the words of their author. 'Man is perennially interesting to man,'
says the great chaotic American thinker; and whatever all-embracing
truth you set before him, you may be sure that man will see in it
chiefly the implications that most closely affect his own happiness and
his own destiny. The biological question of the origin of species is a
sufficiently wide one, but it includes also, among other cases, the
origin of the very familiar species _Homo sapiens_ of Linnæus. Some
theologians jumped at once at the conclusion, right or wrong, that if
Darwinism were true man was nothing more than a developed monkey, the
immortal soul was an exploded myth, the foundations of religion itself
were shattered, and the wave of infidelity was doomed to swamp the whole
of Christendom with its blank nihilism. Scientific men, on the other
hand, drew the conclusion that man must be descended, like other
mammals, from some common early vertebrate ancestor, and that the
current views of his origin and destiny must be largely modified by the
evolutionary creed. Of this profound scientific belief Professor
Huxley's maiden work was the earliest outcome.
Meantime, on the continent of Europe and over-sea in America, the
Darwinian theory was being hotly debated and warmly defended. France,
coldly sceptical and critical, positive rather than imaginative in
matters of science, and little prone by native cast of mind to the
evolutionary attitude, stood aloof to a great extent from the onward
course of the general movement. Here and there, to be sure, a Gaudry or
a Ribot, a Delboeuf or a De Candolle (the two latter a Liège Belgian and
a Genevan Swiss) might heartily throw himself into the new ideas, and
contribute whole squadrons of geological or botanical fact to the final
victory. Yet, as a whole, the dry and cautious French intelligence, ever
inclined to a scientific opportunism, preferred for the moment to stand
by expectant and await the result of the European consensus. But
philosophical Germany, on the other hand, beaming enthusiasm from its
myriad spectacles, eagerly welcomed the novel ideas, and proclaimed from
the housetops the evolutionary faith as a main plank in the rising
platform of the newly-roused Kulturkampf. Fritz Müller began with all
the ardour of a fresh convert to collect his admirable 'Facts for
Darwin;' his brother Hermann sat down with indomitable patience, like
the master's own, to watch the ceaseless action of the bees and
butterflies in the fertilisation of flowers. Rütimeyer applied the
Darwinian principles to the explanation of mammalian relationships, and
Haeckel set to work upon his vast reconstructive 'History of Creation,'
a largely speculative work which, with all its faults, distinctly
carried forward the evolutionary impulse, and set fresh researchers
working upon new lines, to confirm or to disprove its audacious
imaginings. In America, Asa Gray gave to the young creed the high
authority of his well-known name, and Chauncey Wright helped it onward
on the road with all the restrained force of his singular and oblique
but powerful and original personality. If Agassiz and Dawson still
hesitated, Fiske and Youmans were ardent in the faith. If critical
Boston put up its eye-glass doubtfully, Chicago and St. Louis were ready
for conversion. Everywhere Darwin and Darwinism became as household
words; it was the singular fate of the great prophet of evolution, alone
almost among the sons of men, to hear his own name familiarly twisted
during his own lifetime into a colloquial adjective, and to see the
Darwinian theory and the errors of Darwinism staring him in the face a
hundred times a day from every newspaper and every periodical.
Of course the 'Origin of Species' was largely translated at once into
all the civilised languages of Europe, Russian as well as French, Dutch
as well as German, Swedish as well as Italian, Spanish as well as
Hungarian, nay even, at last, transcending narrow continental limits,
Japanese as well as Hindustani. The revolution which it was rapidly
effecting was indeed a revolution in every mode of thought and feeling
as well as a revolution in mere restricted biological opinion. But all
this time, the modest, single-minded, and unassuming author was working
unmoved among his plants and pigeons in his home at Down, regardless of
the European fame he was so quickly acquiring, and anxious only to bring
to a termination the vast work which he still contemplated. A little
more than eleven years intervened between the publication of the 'Origin
of Species,' in 1859, and the first appearance of the 'Descent of Man,'
in 1871. The interval was occupied in carrying out in part the gigantic
scheme of his original collections for the full treatment of the
development theory. The work published in 1859 Darwin regarded merely as
an abstract and preliminary outline of his full opinions: 'No one can
feel more sensible than I do,' he wrote, 'of the necessity of hereafter
publishing in detail all the facts, with references, on which my
conclusions have been grounded.' The marvellously learned work on the
'Variation of Animals and Plants under Domestication,' which came out in
two volumes in 1867, formed the first instalment of this long-projected
treatise. The second part, as he told Mr. Fiske, was to have treated of
the variation of animals and plants through natural selection; while the
third part would have dealt at length with the phenomena of morphology,
of classification, and of distribution in space and time. But these
latter portions of the work were never written. To say the truth, they
were never needed. So universal was the recognition among the younger
men of Darwin's discovery, that before ten years were over innumerable
workers were pushing out the consequences of natural selection into
every field of biology and palæontology. It seemed no longer so
necessary as it had once seemed to write the larger and more elaborate
treatise he had originally contemplated.
The volume on the variation of animals and plants contained also
Darwin's one solitary contribution to the pure speculative philosophy of
life--his 'Provisional Hypothesis of Pangenesis,' by which he strove to
account on philosophical principles for the general facts of physical
and mental heredity. Not to mince matters, it was his one conspicuous
failure, and is now pretty universally admitted as such. Let not the
love of the biographer deceive us; Darwin was here attempting a task
_ultra vires_. As already observed, his mind, vast as it was, leaned
rather to the concrete than to the abstract side: he lacked the
distinctively metaphysical and speculative twist. Strange to say, too,
his abortive theory appeared some years later than Herbert Spencer's
magnificent all-sided conception of 'Physiological Units,' put forth
expressly to meet the self-same difficulty. But while Darwin's
hypothesis is rudely materialistic, Herbert Spencer's is built up by an
acute and subtle analytical perception of all the analogous facts in
universal nature. It is a singular instance of a crude and essentially
unphilosophic conception endeavouring to replace a finished and delicate
philosophical idea.
Earlier still, in 1862, Darwin had published his wonderful and
fascinating book on the 'Fertilisation of Orchids.' It is delightful to
contemplate the picture of the unruffled naturalist, in the midst of
that universal storm of ecclesiastical obloquy and scientific enthusiasm
which he had roused throughout Europe, sitting down calmly in his
Kentish conservatory to watch the behaviour of catasetums and
masdevallias, and to work out the details of his chosen subject, with
that marvellous patience of which he was so great a master, in the
pettiest minutiæ of fertilisation as displayed by a single highly
developed family of plants. Whoever wishes to learn the full profundity
of Darwin's researches, into every point that he set himself to
investigate, cannot do better than turn for a while to the consideration
of that exquisite treatise on one of the quaintest fairylands of
science. He will there learn by what an extraordinary wealth of cunning
devices natural selection has ensured the due conveyance of the
fecundating pollen from stamens to stigmas within the limits of a single
group of vegetable organisms. Here the fertilising mass is gummed
automatically between the eyes of the exploring bee, and then bent round
by the drying of its stalk so as to come in contact with the stigmatic
surface. There the pollen club is jerked out elastically by a sensitive
fibre, and actually flung by its irritable antennæ at the unconscious
head of the fertilising insect. In one case, the lip of the flower
secretes moisture and forms a sort of cold bath, which wets the wings of
the bees, so compelling them to creep out of the bucket by a passage
close to the anthers and stigma; in another case, the honey is concealed
at the bottom of so long a tube that only the proper fertilising moth
with a proboscis of ten or eleven inches in length can probe the deep
recess in which it is hidden. These, and a hundred other similar
instances, were all carefully considered and described by the great
naturalist as the by-work with which he filled up one of the intervals
between his greater and more comprehensive treatises.
In the decade between 1860 and 1870 the progress of Darwinism was rapid
and continuous. One by one, the few scientific men who still held out
were overborne by the weight of evidence. Geology kept supplying fresh
instances of transitional forms; the progress of research in unexplored
countries kept adding to our knowledge of existing intermediate species
and varieties. During those ten years, Herbert Spencer published his
'First Principles,' his 'Biology,' and the remodelled form of his
'Psychology;' Huxley brought out 'Man's Place in Nature,' the 'Lectures
on Comparative Anatomy,' and the 'Introduction to the Classification of
Animals;' Wallace produced his 'Malay Archipelago' and his
'Contributions to the Theory of Natural Selection;' and Galton wrote his
admirable work on 'Hereditary Genius,' of which his own family is so
remarkable an instance. Tyndall and Lewes had long since signified their
warm adhesion. At Oxford, Rolleston was bringing up a fresh generation
of young biologists in the new faith; at Cambridge, Darwin's old
university, a whole school of brilliant and accurate physiologists was
beginning to make itself both felt and heard in the world of science. In
the domain of anthropology, Tylor was welcoming the assistance of the
new ideas, while Lubbock was engaged on his kindred investigations into
the Origin of Civilisation and the Primitive Condition of Man. All these
diverse lines of thought both showed the wide-spread influence of
Darwin's first great work, and led up to the preparation of his second,
in which he dealt with the history and development of the human race.
And what was thus true of England was equally true of the civilised
world, regarded as a whole: everywhere the great evolutionary movement
was well in progress; everywhere the impulse sent forth from that quiet
Kentish home was permeating and quickening the entire pulse of
intelligent humanity.
Why was it that the 'Origin of Species' possessed this extraordinary
vitalising and kinetic power, this germinal energy, this contagious
force, beyond all other forms of evolutionism previously promulgated?
Why did the world, that listened so coldly to Lamarck and Chambers, turn
so ready an ear to Charles Darwin and natural selection? Partly, no
doubt, because in the fulness of time the moment had come and the
prophet had arisen. All great movements are long brewing, and burst out
at last (like the Reformation and the French Revolution) with explosive
energy. But the cause is largely to be found, also, I believe, in the
peculiar nature of the Darwinian solution. True, a thoroughly logical
mind, a mind of the very highest order, would have said even before
Darwin, 'Creation can have no possible place in the physical series of
things at all. How organisms came to be I do not yet exactly see; but I
am sure they must have come to be by some merely physical process, if we
could only find it out.' And such minds were all actually evolutionary
even before Darwin had made the _modus operandi_ of evolution
intelligible. But most people are not so clear-sighted. They require to
have everything proved to them by the strictest collocation of actual
instances. They will not believe unless one rise from the dead. There
are men who rejected the raw doctrine of special creation on evidence
adduced; and there are men who never even for a moment entertained it as
conceivable. The former compose the mass of the scientific world, and it
was for their conversion that the Darwinian hypothesis was so highly
salutary. As Professor Fiske rightly remarks, 'The truth is that before
the publication of the "Origin of Species" there was no opinion whatever
current respecting the subject that deserved to be called a scientific
hypothesis. That the more complex forms of life must have come into
existence through some process of development from simpler forms was no
doubt the only sensible and rational view to take of the subject; but in
a vague and general opinion of this sort there is nothing that is
properly scientific. A scientific hypothesis must connect the phenomena
with which it deals by alleging a "true cause;" and before 1859 no one
had suggested a "true cause" for the origination of new species,
although the problem was one over which every philosophical naturalist
had puzzled since the beginning of the century. This explains why Mr.
Darwin's success was so rapid and complete, and it also explains why he
came so near being anticipated.' To put it briefly, _a priori_, creation
is from the very first unbelievable; but, as a matter of evidence,
Lamarck failed to make evolution comprehensible, or to give a rationale
of its mode of action, while Darwin's theory of natural selection
succeeded in doing so for those who awaited _a posteriori_ proof. Hence
Darwin was able to convert the world, where Lamarck had only been able
to stir up enquiry among the picked spirits of the scientific and
philosophical coterie. Therein lies the true secret of his rapid, his
brilliant, and his triumphant progress. He had found out not only _that_
it was so, but _how_ it was so, too. In Aristotelian phrase, he had
discovered the _πῶς_ as well as the _ὅτι_.