not get a satisfying supply of nectar, and if these were the only moths
in the country the flowers would undoubtedly suffer, and the further
growth of the nectary be checked by exactly the same process which had
led to its increase. But there are an immense variety of moths, of
various lengths of proboscis, and as the nectary became longer, other
and larger species would become the fertilizers, and would carry on the
process till the largest moths became the sole agents. Now, if not
before, the moth would also be affected, for those with the longest
probosces would get most food, would be the strongest and most vigorous,
would visit and fertilize the greatest number of flowers, and would
leave the largest number of descendants. The flowers most completely
fertilized by these moths being those which had the longest nectaries,
there would in each generation be on the average an increase in the
length of the nectaries, and also an average increase in the length of
the probosces of the moths; and this would be a _necessary result_ from
the fact that nature ever fluctuates about a mean, or that in every
generation there would be flowers with longer and shorter nectaries, and
moths with longer and shorter probosces than the average. No doubt there
are a hundred causes that might have checked this process before it had
reached the point of development at which we find it. If, for instance,
the variation in the quantity of nectar had been at any stage greater
than the variation in the length of the nectary, then smaller moths
could have reached it and have effected the fertilization. Or if the
growth of the probosces of the moths had from other causes increased
quicker than that of the nectary, or if the increased length of
proboscis had been injurious to them in any way, or if the species of
moth with the longest proboscis had become much diminished by some enemy
or other unfavourable conditions, then, in any of these cases, the
shorter nectaried flowers, which would have attracted and could have
been fertilized by the smaller kinds of moths, would have had the
advantage. And checks of a similar nature to these no doubt have acted
in other parts of the world, and have prevented such an extraordinary
development of nectary as has been produced by favourable conditions in
Madagascar only, and in one single species of Orchid. I may here mention
that some of the large Sphinx moths of the tropics have probosces nearly
as long as the nectary of Angraecum sesquipedale. I have carefully
measured the proboscis of a specimen of Macrosila cluentius from South
America, in the collection of the British Museum, and find it to be nine
inches and a quarter long! One from tropical Africa (Macrosila morganii)
is seven inches and a half. A species having a proboscis two or three
inches longer could reach the nectar in the largest flowers of Angraecum
sesquipedale, whose nectaries vary in length from ten to fourteen
inches. That such a moth exists in Madagascar may be safely predicted;
and naturalists who visit that island should search for it with as much
confidence as Astronomers searched for the planet Neptune,--and I
venture to predict they will be equally successful!
Now, instead of this beautiful self-acting adjustment, the opposing
theory is, that the Creator of the Universe, by a direct act of his
Will, so disposed the natural forces influencing the growth of this one
species of plant as to cause its nectary to increase to this enormous
length; and at the same time, by an equally special act, determined the
flow of nourishment in the organization of the moth, so as to cause its
proboscis to increase in exactly the same proportion, having previously
so constructed the Angraecum that it could only be maintained in
existence by the agency of this moth. But what proof is given or
suggested that this was the mode by which the adjustment took place?
None whatever, except a feeling that there is an adjustment of a
delicate kind, and an inability to see how known causes could have
produced such an adjustment. I believe I have shown, however, that such
an adjustment is not only possible but inevitable, unless at some point
or other we deny the action of those simple laws which we have already
admitted to be but the expressions of existing facts.
_Adaptation brought about by General Laws._
It is difficult to find anything like parallel cases in inorganic
nature, but that of a river may perhaps illustrate the subject in some
degree. Let us suppose a person totally ignorant of Modern Geology to
study carefully a great River System. He finds in its lower part, a deep
broad channel filled to the brim, flowing slowly through a flat country
and carrying out to the sea a quantity of fine sediment. Higher up it
branches into a number of smaller channels, flowing alternately through
flat valleys and between high banks; sometimes he finds a deep rocky bed
with perpendicular walls, carrying the water through a chain of hills;
where the stream is narrow he finds it deep, where wide shallow. Further
up still, he comes to a mountainous region, with hundreds of streams and
rivulets, each with its tributary rills and gullies, collecting the
water from every square mile of surface, and every channel adapted to
the water that it has to carry. He finds that the bed of every branch,
and stream, and rivulet, has a steeper and steeper slope as it
approaches its sources, and is thus enabled to carry off the water from
heavy rains, and to bear away the stones and pebbles and gravel, that
would otherwise block up its course. In every part of this system he
would see exact adaptation of means to an end. He would say, that this
system of channels must have been designed, it answers its purpose so
effectually. Nothing but a mind could have so exactly adapted the slopes
of the channels, their capacity, and frequency, to the nature of the
soil and the quantity of the rainfall. Again, he would see special
adaptation to the wants of man, in broad quiet navigable rivers flowing
through fertile plains that support a large population, while the rocky
streams and mountain torrents, were confined to those sterile regions
suitable only for a small population of shepherds and herdsmen. He would
listen with incredulity to the Geologist, who assured him, that the
adaptation and adjustment he so admired was an inevitable result of the
action of general laws. That the rains and rivers, aided by subterranean
forces, had modelled the country, had formed the hills and valleys, had
scooped out the river beds, and levelled the plains;--and it would only
be after much patient observation and study, after having watched the
minute changes produced year by year, and multiplying them by thousands
and ten thousands, after visiting the various regions of the earth and
seeing the changes everywhere going on, and the unmistakable signs of
greater changes in past times,--that he could be made to understand that
the surface of the earth, however beautiful and harmonious it may
appear, is strictly due in every detail to the action of forces which
are demonstrably self-adjusting.
Moreover, when he had sufficiently extended his inquiries, he would
find, that every evil effect which he would imagine must be the result
of non-adjustment does somewhere or other occur, only it is not always
evil. Looking on a fertile valley, he would perhaps say--"If the channel
of this river were not well adjusted, if for a few miles it sloped the
wrong way, the water could not escape, and all this luxuriant valley,
full of human beings, would become a waste of waters." Well, there are
hundreds of such cases. Every lake is a valley "wasted by water," and in
some cases (as the Dead Sea) it is a positive evil, a blot upon the
harmony and adaptation of the surface of the earth. Again, he might
say--"If rain did not fall here, but the clouds passed over us to some
other regions, this verdant and highly cultivated plain would become a
desert." And there are such deserts over a large part of the earth,
which abundant rains would convert into pleasant dwelling-places for
man. Or he might observe some great navigable river, and reflect how
easily rocks, or a steeper channel in places, might render it useless to
man;--and a little inquiry would show him hundreds of rivers in every
part of the world, which are thus rendered useless for navigation.
Exactly the same thing occurs in organic nature. We see some one
wonderful case of adjustment, some unusual development of an organ, but
we pass over the hundreds of cases in which that adjustment and
development do not occur. No doubt when one adjustment is absent another
takes its place, because no organism can continue to exist that is not
adjusted to its environment; and unceasing variation with unlimited
powers of multiplication, in most cases, furnish the means of
self-adjustment. The world is so constituted, that by the action of
general laws there is produced the greatest possible variety of surface
and of climate; and by the action of laws equally general, the greatest
possible variety of organisms have been produced, adapted to the varied
conditions of every part of the earth. Tho objector would probably
himself admit, that the varied surface of the earth--the plains and
valleys, the hills and mountains, the deserts and volcanoes, the winds
and currents, the seas and lakes and rivers, and the various climates of
the earth--are all the results of general laws acting and re-acting
during countless ages; and that the Creator does not appear to guide and
control the action of these laws--here determining the height of a
mountain, there altering the channel of a river--here making the rains
more abundant, there changing the direction of a current. He would
probably admit that the forces of inorganic nature are self-adjusting,
and that the result necessarily fluctuates about a given mean condition
(which is itself slowly changing), while within certain limits the
greatest possible amount of variety is produced. If then a "contriving
mind" is not necessary at every step of the process of change eternally
going on in the inorganic world, why are we required to believe in the
continual action of such a mind in the region of organic nature? True,
the laws at work are more complex, the adjustments more delicate, the
appearance of special adaptation more remarkable; but why should we
measure the creative mind by our own? Why should we suppose the machine
too complicated, to have been designed by the Creator so complete that
it would necessarily work out harmonious results? The theory of
"continual interference" is a limitation of the Creator's power. It
assumes that he could not work by pure law in the organic, as he has
done in the inorganic world; it assumes that he could not foresee the
consequences of the laws of matter and mind combined--that results would
continually arise which are contrary to what is best, and that he has to
change what would otherwise be the course of nature, in order to produce
that beauty, and variety, and harmony, which even we, with our limited
intellects, can conceive to be the result of self-adjustment in a
universe governed by unvarying law. If we could not conceive the world
of nature to be self-adjusting and capable of endless development, it
would even then be an unworthy idea of a Creator, to impute the
incapacity of our minds to him; but when many human minds can conceive,
and can even trace out in detail some of the adaptations in nature as
the necessary results of unvarying law, it seems strange that, in the
interests of religion, any one should seek to prove that the System of
Nature, instead of being above, is far below our highest conceptions of
it. I, for one, cannot believe that the world would come to chaos if
left to Law alone. I cannot believe that there is in it no inherent
power of developing beauty or variety, and that the direct action of the
Deity is required to produce each spot or streak on every insect, each
detail of structure in every one of the millions of organisms that live
or have lived upon the earth. For it is impossible to draw a line. If
any modifications of structure could be the result of law, why not all?
If some self-adaptations could arise, why not others? If any varieties
of colour, why not all the varieties we see? No attempt is made to
explain this, except by reference to the fact that "purpose" and
"contrivance" are everywhere visible, and by the illogical deduction
that they could only have arisen from the direct action of some mind,
because the direct action of our minds produces similar "contrivances";
but it is forgotten that adaptation, however produced, must have the
appearance of design. The channel of a river looks as if made _for_ the
river, although it is made _by_ it; the fine layers and beds in a
deposit of sand, often look as if they had been sorted, and sifted, and
levelled, designedly; the sides and angles of a crystal exactly resemble
similar forms designed by man; but we do not therefore conclude that
these effects have, in each individual case, required the directing
action of a creative mind, or see any difficulty in their being produced
by natural Law.
_Beauty in Nature._
Let us, however, leave this general argument for a while, and turn to
another special case, which has been appealed to as conclusive against
Mr. Darwin's views. "Beauty" is, to some persons, as great a
stumbling-block as "contrivance." They cannot conceive a system of the
Universe, so perfect, as necessarily to develop every form of Beauty,
but suppose that when anything specially beautiful occurs, it is a step
beyond what that system could have produced, something which the Creator
has added for his own delectation.
Speaking of the Humming Birds, the Duke of Argyll says: "In the first
place, it is to be observed of the whole group, that there is no
connection which can be traced or conceived, between the splendour of
the humming birds and any function essential to their life. If there
were any such connection, that splendour could not be confined, as it
almost exclusively is, to only one sex. The female birds are, of course,
not placed at any disadvantage in the struggle for existence by their
more sombre colouring." And after describing the various ornaments of
these birds, he says: "Mere ornament and variety of form, and these for
their own sake, is the only principle or rule with reference to which
Creative Power seems to have worked in these wonderful and beautiful
birds.... A crest of topaz is no better in the struggle for existence
than a crest of sapphire. A frill ending in spangles of the emerald is
no better in the battle of life than a frill ending in spangles of the
ruby. A tail is not affected for the purposes of flight, whether its
marginal or its central feathers are decorated with white.... Mere
beauty and mere variety, for their own sake, are objects which we
ourselves seek when we can make the Forces of Nature subordinate to the
attainment of them. There seems to be no conceivable reason why we
should doubt or question, that these are ends and aims also in the forms
given to living organisms" ("Reign of Law," p. 248).
Here the statement that "no connection can be conceived between the
splendour of the humming birds and any function essential to their
life," is met by the fact, that Mr. Darwin has not only conceived but
has shown, both by observation and reasoning, how beauty of colour and
form may have a direct influence on the most important of all the
functions of life, that of reproduction. In the variations to which
birds are subject, any more brilliant colour than usual would be
attractive to the females, and would lead to the individuals so adorned
leaving more than the average number of offspring. Experiment and
observation have shown, that this kind of sexual selection does actually
take place; and the laws of inheritance would necessarily lead to the
further development of any individual peculiarity that was attractive,
and thus the splendour of the humming birds is directly connected with
their very existence. It is true that "a crest of topaz may be no better
than a crest of sapphire," but either of these may be much better than
no crest at all; and the different conditions under which the parent
form must have existed in different parts of its range, will have
determined different variations of tint, either of which were
advantageous. The reason why female birds are not adorned with equally
brilliant plumes is sufficiently clear; they would be injurious, by
rendering their possessors too conspicuous during incubation. Survival
of the fittest, has therefore favoured the development of those dark
green tints on the upper surface of so many female humming birds, which
are most conducive to their protection while the important functions of
hatching and rearing the young are being carried on. Keeping in mind the
laws of multiplication, variation, and survival of the fittest, which
are for ever in action, these varied developments of beauty and
harmonious adjustments to conditions, are not only conceivable but
demonstrable results.
The objection I am now combating is solely founded on the supposed
analogy of the Creator's mind to ours, as regards the love of Beauty for
its own sake; but if this analogy is to be trusted, then there ought to
be no natural objects which are disagreeable or ungraceful in our eyes.
And yet it is undoubtedly the fact that there are many such. Just as
surely as the Horse and Deer are beautiful and graceful, the Elephant,
Rhinoceros, Hippopotamus, and Camel are the reverse. The majority of
Monkeys and Apes are not beautiful; the majority of Birds have no beauty
of colour; a vast number of Insects and Reptiles are positively ugly.
Now, if the Creator's mind is like ours, whence this ugliness? It is
useless to say "that is a mystery we cannot explain," because we have
attempted to explain one-half of creation by a method that will not
apply to the other half. We know that a man with the highest taste and
with unlimited wealth, practically does abolish all ungraceful and
disagreeable forms and colours from his own domains. If the beauty of
creation is to be explained by the Creator's love of beauty, we are
bound to ask why he has not banished deformity from the earth, as the
wealthy and enlightened man does from his estate and from his dwelling;
and if we can get no satisfactory answer, we shall do well to reject the
explanation offered. Again, in the case of flowers, which are always
especially referred to, as the surest evidence of beauty being an end of
itself in creation, the whole of the facts are never fairly met. At
least half the plants in the world have not bright-coloured or beautiful
flowers; and Mr. Darwin has lately arrived at the wonderful
generalization, that flowers have become beautiful solely to attract
insects to assist in their fertilization. He adds, "I have come to this
conclusion from finding it an invariable rule, that when a flower is
fertilized by the wind it never has a gaily-coloured corolla." Here is a
most wonderful case of beauty being _useful_, when it might be least
expected. But much more is proved; for when beauty is of no use to the
plant it is not given. It cannot be imagined to do any harm. It is
simply not necessary, and is therefore withheld! We ought surely to have
been told how this fact is consistent with beauty being "an end in
itself," and with the statement of its being given to natural objects
"for its own sake."
_How new Forms are produced by Variation and Selection._
Let us now consider another of the popular objections which the Duke of
Argyll thus sets forth:--
"Mr. Darwin does not pretend to have discovered any law or rule,
according to which new Forms have been born from old Forms. He does not
hold that outward conditions, however changed, are sufficient to account
for them.... His theory seems to be far better than a mere theory--to be
an established scientific truth--in so far as it accounts, in part at
least, for the success and establishment and spread of new Forms _when
they have arisen_. But it does not even suggest the law under which, or
by or according to which, such new Forms are introduced. Natural
Selection can do nothing, except with the materials presented to its
hands. It cannot select except among the things open to selection....
Strictly speaking, therefore, Mr. Darwin's theory is not a theory on the
Origin of Species at all, but only a theory on the causes which lead to
the relative success or failure of such new forms as may be born into
the world." ("Reign of Law," p. 230.)
In this, and many other passages in his work, the Duke of Argyll sets
forth his idea of Creation as a "Creation by birth," but maintains that
each birth of a new form from parents differing from itself, has been
produced by a special interference of the Creator, in order to direct
the process of development into certain channels; that each new species
is in fact a "special creation," although brought into existence through
the ordinary laws of reproduction. He maintains therefore, that the laws
of multiplication and variation cannot furnish the right kinds of
materials at the right times for natural selection to work on. I
believe, on the contrary, that it can be logically _proved_ from the six
axiomatic laws before laid down, that such materials would be furnished;
but I prefer to show there are abundance of _facts_ which demonstrate
that they are furnished.
The experience of all cultivators of plants and breeders of animals
shows, that when a sufficient number of individuals are examined,
variations of any required kind can always be met with. On this depends
the possibility of obtaining breeds, races, and fixed varieties of
animals and plants; and it is found, that any one form of variation may
be accumulated by selection, without materially affecting the other
characters of the species; each _seems_ to vary in the one required
direction only. For example, in turnips, radishes, potatoes, and
carrots, the root or tuber varies in size, colour, form, and flavour,
while the foliage and flowers seem to remain almost stationary; in the
cabbage and lettuce, on the contrary, the foliage can be modified into
various forms and modes of growth, the root, flower, and fruit remaining
little altered; in the cauliflower and brocoli the flower heads vary; in
the garden pea the pod only changes. We get innumerable forms of fruit
in the apple and pear, while the leaves and flowers remain
undistinguishable; the same occurs in the gooseberry and garden currant.
Directly however, (in the very same genus) we want the flower to vary in
the Ribes sanguineum, it does so, although mere cultivation for hundreds
of years has not produced marked differences in the flowers of Ribes
grossularia. When fashion demands any particular change in the form or
size, or colour of a flower, sufficient variation always occurs in the
right direction, as is shown by our roses, auriculas, and geraniums;
when, as recently, ornamental leaves come into fashion sufficient
variation is found to meet the demand, and we have zoned pelargoniums,
and variegated ivy, and it is discovered that a host of our commonest
shrubs and herbaceous plants have taken to vary in this direction just
when we want them to do so! This rapid variation is not confined to old
and well-known plants subjected for a long series of generations to
cultivation, but the Sikim Rhododendrons, the Fuchsias, and Calceolarias
from the Andes, and the Pelargoniums from the Cape are equally
accommodating, and vary just when and where and how we require them.
Turning to animals we find equally striking examples. If we want any
special quality in any animal we have only to breed it in sufficient
quantities and watch carefully, and the required variety is _always_
found, and can be increased to almost any desired extent. In Sheep, we
get flesh, fat, and wool; in Cows, milk; in Horses, colour, strength,
size, and speed; in Poultry, we have got almost any variety of colour,
curious modifications of plumage, and the capacity of perpetual
egg-laying. In Pigeons we have a still more remarkable proof of the
universality of variation, for it has been at one time or another the
fancy of breeders to change the form of every part of these birds, and
they have never found the required variations absent. The form, size,
and shape of bill and feet, have been changed to such a degree as is
found only in distinct genera of wild birds; the number of tail feathers
has been increased, a character which is generally one of the most
permanent nature, and is of high importance in the classification of
birds; and the size, the colour, and the habits, have been also changed
to a marvellous extent. In Dogs, the degree of modification and the
facility with which it is effected, is almost equally apparent. Look at
the constant amount of variation in opposite directions that must have
been going on, to develop the poodle and the greyhound from the same
original stock! Instincts, habits, intelligence, size, speed, form, and
colour, have always varied, so as to produce the very races which the
wants or fancies or passions of men may have led them to desire. Whether
they wanted a bull-dog to torture another animal, a greyhound to catch
a hare, or a bloodhound to hunt down their oppressed fellow-creatures,
the required variations have always appeared.