LAMARCK AND MR. DARWIN.
IT will have been seen that in the preceding pages the theory of
evolution, as originally propounded by Lamarck, has been more than once
supported, as against the later theory concerning it put forward by Mr.
Darwin, and now generally accepted.
It is not possible for me, within the limits at my command, to do
anything like justice to the arguments that may be brought forward in
favour of either of these two theories. Mr. Darwin’s books are at the
command of every one; and so much has been discovered since Lamarck’s
day, that if he were living now, he would probably state his case very
differently; I shall therefore content myself with a few brief remarks,
which will hardly, however, aspire to the dignity of argument.
According to Mr. Darwin, differentiations of structure and instinct have
mainly come about through the accumulation of small, fortuitous
variations without intelligence or desire upon the part of the creature
varying; modification, however, through desire and sense of need, is not
denied entirely, inasmuch as considerable effect is ascribed by Mr.
Darwin to use and disuse, which involves, as has been already said, the
modification of a structure in accordance with the wishes of its
possessor.
According to Lamarck, genera and species have been evolved, in the main,
by exactly the same process as that by which human inventions and
civilisations are now progressing; and this involves that intelligence,
ingenuity, heroism, and all the elements of romance, should have had the
main share in the development of every herb and living creature around
us.
I take the following brief outline of the most important part of
Lamarck’s theory from vol. xxxvi. of the Naturalist’s Library (Edinburgh,
1843):—
“The more simple bodies,” says the editor, giving Lamarck’s opinion
without endorsing it, “are easily formed, and this being the case, it is
easy to conceive how in the lapse of time animals of a more complex
structure should be produced, _for it must be admitted as a fundamental
law_, _that the production of a new organ in an animal body results from
any new want or desire it may experience_. The first effort of a being
just beginning to develop itself must be to procure subsistence, and
hence in time there comes to be produced a stomach or alimentary cavity.”
(Thus we saw that the amœba is in the habit of “extemporising” a stomach
when it wants one.) “Other wants occasioned by circumstances will lead
to other efforts, which in their turn will generate new organs.”
Lamarck’s wonderful conception was hampered by an unnecessary adjunct,
namely, a belief in an inherent tendency towards progressive development
in every low organism. He was thus driven to account for the presence of
many very low and very ancient organisms at the present day, and fell
back upon the theory, which is not yet supported by evidence, that such
low forms are still continually coming into existence from inorganic
matter. But there seems no necessity to suppose that all low forms
should possess an inherent tendency towards progression. It would be
enough that there should occasionally arise somewhat more gifted
specimens of one or more original forms. These would vary, and the ball
would be thus set rolling, while the less gifted would remain _in statu
quo_, provided they were sufficiently gifted to escape extinction.
Nor do I gather that Lamarck insisted on continued personality and memory
so as to account for heredity at all, and so as to see life as a single,
or as at any rate, only a few, vast compound animals, but without the
connecting organism between each component item in the whole creature,
which is found in animals that are strictly called compound. Until
continued personality and memory are connected with the idea of heredity,
heredity of any kind is little more than a term for something which one
does not understand. But there seems little _à priori_ difficulty as
regards Lamarck’s main idea, now that Mr. Darwin has familiarised us with
evolution, and made us feel what a vast array of facts can be brought
forward in support of it.
Mr. Darwin tells us, in the preface to his last edition of the “Origin of
Species,” that Lamarck was partly led to his conclusions by the analogy
of domestic productions. It is rather hard to say what these words
imply; they may mean anything from a baby to an apple dumpling, but if
they imply that Lamarck drew inspirations from the gradual development of
the mechanical inventions of man, and from the progress of man’s ideas, I
would say that of all sources this would seem to be the safest and most
fertile from which to draw.
Plants and animals under domestication are indeed a suggestive field for
study, but machines are the manner in which man is varying at this
moment. We know how our own minds work, and how our mechanical
organisations—for, in all sober seriousness, this is what it comes
to—have progressed hand in hand with our desires; sometimes the power a
little ahead, and sometimes the desire; sometimes both combining to form
an organ with almost infinite capacity for variation, and sometimes
comparatively early reaching the limit of utmost development in respect
of any new conception, and accordingly coming to a full stop; sometimes
making leaps and bounds, and sometimes advancing sluggishly. Here we are
behind the scenes, and can see how the whole thing works. We have man,
the very animal which we can best understand, caught in the very act of
variation, through his own needs, and not through the needs of others;
the whole process is a natural one; the varying of a creature as much in
a wild state as the ants and butterflies are wild. There is less
occasion here for the continual “might be” and “may be,” which we are
compelled to put up with when dealing with plants and animals, of the
workings of whose minds we can only obscurely judge. Also, there is more
prospect of pecuniary profit attaching to the careful study of machinery
than can be generally hoped for from the study of the lower animals; and
though I admit that this consideration should not be carried too far, a
great deal of very unnecessary suffering will be spared to the lower
animals; for much that passes for natural history is little better than
prying into other people’s business, from no other motive than curiosity.
I would, therefore, strongly advise the reader to use man, and the
present races of man, and the growing inventions and conceptions of man,
as his guide, if he would seek to form an independent judgement on the
development of organic life. For all growth is only somebody making
something.
Lamarck’s theories fell into disrepute, partly because they were too
startling to be capable of ready fusion with existing ideas; they were,
in fact, too wide a cross for fertility; partly because they fell upon
evil times, during the reaction that followed the French Revolution;
partly because, unless I am mistaken, he did not sufficiently link on the
experience of the race to that of the individual, nor perceive the
importance of the principle that consciousness, memory, volition,
intelligence, &c., vanish, or become latent, on becoming intense. He
also appears to have mixed up matter with his system, which was either
plainly wrong, or so incapable of proof as to enable people to laugh at
him, and pooh-pooh him; but I believe it will come to be perceived, that
he has received somewhat scant justice at the hands of his successors,
and that his “crude theories,” as they have been somewhat cheaply called,
are far from having had their last say.
Returning to Mr. Darwin, we find, as we have already seen, that it is
hard to say exactly how much Mr. Darwin differs from Lamarck, and how
much he agrees with him. Mr. Darwin has always maintained that use and
disuse are highly important, and this implies that the effect produced on
the parent should be remembered by the offspring, in the same way as the
memory of a wound is transmitted by one set of cells to succeeding ones,
who long repeat the scar, though it may fade finally away. Also, after
dealing with the manner in which one eye of a young flat-fish travels
round the head till both eyes are on the same side of the fish, he gives
(“Natural Selection,” p. 188, ed. 1875) an instance of a structure “which
apparently owes its origin exclusively to use or habit.” He refers to
the tail of some American monkeys “which has been converted into a
wonderfully perfect prehensile organ, and serves as a fifth hand. A
reviewer,” he continues, . . . “remarks on this structure—‘It is
impossible to believe that in any number of ages the first slight
incipient tendency to grasp, could preserve the lives of the individuals
possessing it, or favour their chance of having and of rearing
offspring.’ But there is no necessity for any such belief. Habit, and
this almost implies that some benefit, great or small, is thus derived,
would in all probability suffice for the work.” If, then, habit can do
this—and it is no small thing to develop a wonderfully perfect prehensile
organ which can serve as a fifth hand—how much more may not habit do,
even though unaided, as Mr. Darwin supposes to have been the case in this
instance, by “natural selection”? After attributing many of the
structural and instinctive differences of plants and animals to the
effects of use—as we may plainly do with Mr. Darwin’s own consent—after
attributing a good deal more to unknown causes, and a good deal to
changed conditions, which are bound, if at all important, to result
either in sterility or variation—how much of the work of originating
species is left for natural selection?—which, as Mr. Darwin admits
(“Natural Selection,” p. 63, ed. 1876), does not _induce variability_,
but “implies only the preservation of _such variations as arise_, and are
beneficial to the being under its conditions of life?” An important part
assuredly, and one which we can never sufficiently thank Mr. Darwin for
having put so forcibly before us, but an indirect part only, like the
part played by time and space, and not, I think, the one which Mr. Darwin
would assign to it.
Mr. Darwin himself has admitted that in the earlier editions of his
“Origin of Species” he “underrated, as it now seems probable, the
frequency and importance of modifications due to spontaneous
variability.” And this involves the having over-rated the action of
“natural selection” as an agent in the evolution of species. But one
gathers that he still believes the accumulation of small and fortuitous
variations through the agency of “natural selection” to be the main cause
of the present divergencies of structure and instinct. I do not,
however, think that Mr. Darwin is clear about his own meaning. I think
the prominence given to “natural selection” in connection with the
“origin of species” has led him, in spite of himself, and in spite of his
being on his guard (as is clearly shown by the paragraph on page 63
“Natural Selection,” above referred to), to regard “natural selection” as
in some way accounting for variation, just as the use of the dangerous
word “spontaneous,”—though he is so often on his guard against it, and so
frequently prefaces it with the words “so-called,”—would seem to have led
him into very serious confusion of thought in the passage quoted at the
beginning of this paragraph.
For after saying that he had underrated “the frequency and importance of
modifications due to spontaneous variability,” he continues, “but it is
impossible to attribute to this cause the innumerable structures which
are so well adapted to the habits of life of each species.” That is to
say, it is impossible to attribute these innumerable structures to
spontaneous variability.
What _is_ spontaneous variability?
Clearly, from his preceding paragraph, Mr. Darwin means only “so-called
spontaneous variations,” such as “the appearance of a moss-rose on a
common rose, or of a nectarine on a peach-tree,” which he gives as good
examples of so-called spontaneous variation.
And these variations are, after all, due to causes, but to unknown
causes; spontaneous variation being, in fact, but another name for
variation due to causes which we know nothing about, but in no possible
sense a _cause of variation_. So that when we come to put clearly before
our minds exactly what the sentence we are considering amounts to, it
comes to this: that it is impossible to attribute the innumerable
structures which are so well adapted to the habits of life of each
species to _unknown causes_.
“I can no more believe in _this_,” continues Mr. Darwin, “than that the
well-adapted form of a race-horse or greyhound, which, before the
principle of selection by man was well understood, excited so much
surprise in the minds of the older naturalists, can _thus_ be explained”
(“Natural Selection,” p. 171, ed. 1876).
Or, in other words, “I can no more believe that the well-adapted
structures of species are due to unknown causes, than I can believe that
the well-adapted form of a race-horse can be explained by being
attributed to unknown causes.”
I have puzzled over this paragraph for several hours with the sincerest
desire to get at the precise idea which underlies it, but the more I have
studied it the more convinced I am that it does not contain, or at any
rate convey, any clear or definite idea at all. If I thought it was a
mere slip, I should not call attention to it; this book will probably
have slips enough of its own without introducing those of a great man
unnecessarily; but I submit that it is necessary to call attention to it
here, inasmuch as it is impossible to believe that after years of
reflection upon his subject, Mr. Darwin should have written as above,
especially in such a place, if his mind was really clear about his own
position. Immediately after the admission of a certain amount of
miscalculation, there comes a more or less exculpatory sentence which
sounds so right that ninety-nine people out of a hundred would walk
through it, unless led by some exigency of their own position to examine
it closely but which yet upon examination proves to be as nearly
meaningless as a sentence can be.
The weak point in Mr. Darwin’s theory would seem to be a deficiency, so
to speak, of motive power to originate and direct the variations which
time is to accumulate. It deals admirably with the accumulation of
variations in creatures already varying, but it does not provide a
sufficient number of sufficiently important variations to be accumulated.
Given the motive power which Lamarck suggested, and Mr. Darwin’s
mechanism would appear (with the help of memory, as bearing upon
reproduction, of continued personality, and hence of inherited habit, and
of the vanishing tendency of consciousness) to work with perfect ease.
Mr. Darwin has made us all feel that in some way or other variations _are
accumulated_, and that evolution is the true solution of the present
widely different structures around us, whereas, before he wrote, hardly
any one believed this. However we may differ from him in detail, the
present general acceptance of evolution must remain as his work, and a
more valuable work can hardly be imagined. Nevertheless, I cannot think
that “natural selection,” working upon small, fortuitous, indefinite,
unintelligent variations, would produce the results we see around us.
One wants something that will give a more definite aim to variations, and
hence, at times, cause bolder leaps in advance. One cannot but doubt
whether so many plants and animals would be being so continually saved
“by the skin of their teeth,” as must be so saved if the variations from
which genera ultimately arise are as small in their commencement and at
each successive stage as Mr. Darwin seems to believe. God—to use the
language of the Bible—is not extreme to mark what is done amiss, whether
with plant or beast or man; on the other hand, when towers of Siloam
fall, they fall on the just as well as the unjust.
One feels, on considering Mr. Darwin’s position, that if it be admitted
that there is in the lowest creature a power to vary, no matter how
small, one has got in this power as near the “origin of species” as one
can ever hope to get. For no one professes to account for the origin of
life; but if a creature with a power to vary reproduces itself at all, it
must reproduce another creature _which shall also have the power to
vary_; so that, given time and space enough, there is no knowing where
such a creature could or would stop.
If the primordial cell had been only capable of reproducing itself once,
there would have followed a single line of descendants, the chain of
which might at any moment have been broken by casualty. Doubtless the
millionth repetition would have differed very materially from the
original—as widely, perhaps, as we differ from the primordial cell; but
it would only have differed by addition, and could no more in any
generation resume its latest development without having passed through
the initial stage of being what its first forefather was, and doing what
its first forefather did, and without going through all or a sufficient
number of the steps whereby it had reached its latest differentiation,
than water can rise above its own level.
The very idea, then, of reproduction involves, unless I am mistaken,
that, no matter how much the creature reproducing itself may gain in
power and versatility, it must still always begin _with itself again_ in
each generation. The primordial cell being capable of reproducing itself
not only once, but many times over, each of the creatures which it
produces must be similarly gifted; hence the geometrical ratio of
increase and the existing divergence of type. In each generation it will
pass rapidly and unconsciously through all the earlier stages of which
there has been infinite experience, and for which the conditions are
reproduced with sufficient similarity to cause no failure of memory or
hesitation; but in each generation, when it comes to the part in which
the course is not so clear, it will become conscious; still, however,
where the course is plain, as in breathing, digesting, &c., retaining
unconsciousness. Thus organs which present all the appearance of being
designed—as, for example, the tip for its beak prepared by the embryo
chicken—would be prepared in the end, as it were, by rote, and without
sense of design, though none the less owing their origin to design.
The question is not concerning evolution, but as to the main cause which
has led to evolution in such and such shapes. To me it seems that the
“Origin of Variation,” whatever it is, is the only true “Origin of
Species,” and that this must, as Lamarck insisted, be looked for in the
needs and experiences of the creatures varying. Unless we can explain
the origin of variations, we are met by the unexplained _at every step_
in the progress of a creature from its original homogeneous condition to
its differentiation, we will say, as an elephant; so that to say that an
elephant has become an elephant through the accumulation of a vast number
of small, fortuitous, but unexplained, variations in some lower
creatures, is really to say that it has become an elephant owing to a
series of causes about which we know nothing whatever, or, in other
words, that one does not know how it came to be an elephant. But to say
that an elephant has become an elephant owing to a series of variations,
nine-tenths of which were caused by the wishes of the creature or
creatures from which the elephant is descended—this is to offer a reason,
and definitely put the insoluble one step further back. The question
will then turn upon the sufficiency of the reason—that is to say, whether
the hypothesis is borne out by facts.
The effects of competition would, of course, have an extremely important
effect upon any creature, in the same way as any other condition of
nature under which it lived, must affect its sense of need and its
opinions generally. The results of competition would be, as it were, the
decisions of an arbiter settling the question whether such and such
variation was really to the animal’s advantage or not—a matter on which
the animal will, on the whole, have formed a pretty fair judgement for
itself. _Undoubtedly the past decisions of such an arbiter would affect
the conduct of the creature_, which would have doubtless had its
shortcomings and blunders, and would amend them. The creature would
shape its course according to its experience of the common course of
events, but it would be continually trying and often successfully, to
evade the law by all manner of sharp practice. New precedents would thus
arise, so that the law would shift with time and circumstances; but the
law would not otherwise direct the channels into which life would flow,
than as laws, whether natural or artificial, have affected the
development of the widely differing trades and professions among mankind.
These have had their origin rather in the needs and experiences of
mankind than in any laws.
To put much the same as the above in different words. Assume that small
favourable variations are preserved more commonly, in proportion to their
numbers, than is perhaps the case, and assume that considerable
variations occur more rarely than they probably do occur, how account for
any variation at all? “Natural selection” cannot _create_ the smallest
variation unless it acts through perception of its mode of operation,
recognised inarticulately, but none the less clearly, by the creature
varying. “Natural selection” operates on what it finds, and not on what
it has made. Animals that have been wise and lucky live longer and breed
more than others less wise and lucky. Assuredly. The wise and lucky
animals transmit their wisdom and luck. Assuredly. They add to their
powers, and diverge into widely different directions. Assuredly. What
is the cause of this? Surely the fact that they were capable of feeling
needs, and that they differed in their needs and manner of gratifying
them, and that they continued to live in successive generations, rather
than the fact that when lucky and wise they thrived and bred more
descendants. This last is an accessory hardly less important for the
_development_ of species than the fact of the continuation of life at
all; but it is an accessory of much the same kind as this, for if animals
continue to live at all, they must live _in some way_, and will find that
there are good ways and bad ways of living. An animal which discovers
the good way will gradually develop further powers, and so species will
get further and further apart; but the origin of this is to be looked
for, not in the power which decides whether this or that way was good,
but in the cause which determines the creature, consciously or
unconsciously, to try this or that way.
But Mr. Darwin might say that this is not a fair way of stating the
issue. He might say, “You beg the question; you assume that there is an
inherent tendency in animals towards progressive development, whereas I
say that there is no good evidence of any such tendency. I maintain that
the differences that have from time to time arisen have come about mainly
from causes so far beyond our ken, that we can only call them
spontaneous; and if so, natural selection which you must allow to have at
any rate played an important part in the _accumulation_ of variations,
must also be allowed to be the nearest thing to the cause of Specific
differences, which we are able to arrive at.”
Thus he writes (“Natural Selection,” p. 176, ed. 1876): “Although we have
no good evidence of the existence in organic beings of a tendency towards
progressive development, yet this necessarily follows, as I have
attempted to show in the fourth chapter, through the continued action of
natural selection.” Mr. Darwin does not say that organic beings have no
tendency to vary at all, but only that there is no good evidence that
they have a tendency to progressive development, which, I take it, means,
to see an ideal a long way off, and very different to their present
selves, which ideal they think will suit them, and towards which they
accordingly make. I would admit this as contrary to all experience. I
doubt whether plants and animals have any _innate tendency to vary_ at
all, being led to question this by gathering from “Plants and Animals
under Domestication” that this is Mr. Darwin’s own opinion. I am
inclined rather to think that they have only an innate _power to vary_
slightly, in accordance with changed conditions, and an innate capability
of being affected both in structure and instinct, by causes similar to
those which we observe to affect ourselves. But however this may be,
they do vary somewhat, and unless they did, they would not in time have
come to be so widely different from each other as they now are. The
question is as to the origin and character of these variations.
We say they mainly originate in a creature through a sense of its needs,
and vary through the varying surroundings which will cause those needs to
vary, and through the opening up of new desires in many creatures, as the
consequence of the gratification of old ones; they depend greatly on
differences of individual capacity and temperament; they are
communicated, and in the course of time transmitted, as what we call
hereditary habits or structures, though these are only, in truth, intense
and epitomised memories of how certain creatures liked to deal with
protoplasm. The question whether this or that is really good or ill, is
settled, as the proof of the pudding by the eating thereof, _i.e._, by
the rigorous competitive examinations through which most living organisms
must pass. Mr. Darwin says that there is no good evidence in support of
any great principle, or tendency on the part of the creature itself,
which would steer variation, as it were, and keep its head straight, but
that the most marvellous adaptations of structures to needs are simply
the result of small and blind variations, accumulated by the operation of
“natural selection,” which is thus the main cause of the origin of
species.
Enough has perhaps already been said to make the reader feel that the
question wants reopening; I shall, therefore, here only remark that we
may assume no fundamental difference as regards intelligence, memory, and
sense of needs to exist between man and the lowest animals, and that in
man we do distinctly see a tendency towards progressive development,
operating through his power of profiting by and transmitting his
experience, but operating in directions which man cannot foresee for any
long distance. We also see this in many of the higher animals under
domestication, as with horses which have learnt to canter and dogs which
point; more especially we observe it along the line of latest
development, where equilibrium of settled convictions has not yet been
fully attained. One neither finds nor expects much _a priori_ knowledge,
whether in man or beast; but one does find some little in the beginnings
of, and throughout the development of, every habit, at the commencement
of which, and on every successive improvement in which, deductive and
inductive methods are, as it were, fused. Thus the effect, where we can
best watch its causes, seems mainly produced by a desire for a definite
object—in some cases a serious and sensible desire, in others an idle
one, in others, again, a mistaken one; and sometimes by a blunder which,
in the hands of an otherwise able creature, has turned up trumps. In
wild animals and plants the divergences have been accumulated, if they
answered to the prolonged desires of the creature itself, and if these
desires were to its true ultimate good; with plants or animals under
domestication they have been accumulated if they answered a little to the
original wishes of the creature, and much, to the wishes of man. As long
as man continued to like them, they would be advantageous to the
creature; when he tired of them, they would be disadvantageous to it, and
would accumulate no longer. Surely the results produced in the
adaptation of structure to need among many plants and insects are better
accounted for on this, which I suppose to be Lamarck’s view, namely, by
supposing that what goes on amongst ourselves has gone on amongst all
creatures, than by supposing that these adaptations are the results of
perfectly blind and unintelligent variations.
Let me give two examples of such adaptations, taken from Mr. St. George
Mivart’s “Genesis of Species,” to which work I would wish particularly to
call the reader’s attention. He should also read Mr. Darwin’s answers to
Mr. Mivart (p. 176, “Natural Selection,” ed. 1876, and onwards).
Mr. Mivart writes:—
“Some insects which imitate leaves extend the imitation even to the very
injuries on those leaves made by the attacks of insects or fungi. Thus
speaking of the walking-stick insects, Mr. Wallace says, ‘One of these
creatures obtained by myself in Borneo (_ceroxylus laceratus_) was
covered over with foliaceous excrescences of a clear olive green colour,
so as exactly to resemble a stick grown over by a creeping moss or
jungermannia. The Dyak who brought it me assured me it was grown over
with moss, though alive, and it was only after a most minute examination
that I could convince myself it was not so.’ Again, as to the leaf
butterfly, he says, ‘We come to a still more extraordinary part of the
imitation, for we find representations of leaves in every stage of decay,
variously blotched, and mildewed, and pierced with holes, and in many
cases irregularly covered with powdery black dots, gathered into patches
and spots so closely resembling the various kinds of minute fungi that
grow on dead leaves, that it is impossible to avoid thinking at first
sight that the butterflies themselves have been attacked by real fungi.’”
I can no more believe that these artificial fungi in which the moth
arrays itself are due to the accumulation of minute, perfectly blind, and
unintelligent variations, than I can believe that the artificial flowers
which a woman wears in her hat can have got there without design; or that
a detective puts on plain clothes without the slightest intention of
making his victim think that he is not a policeman.
Again Mr. Mivart writes:—
“In the work just referred to (‘The Fertilisation of Orchids’), Mr.
Darwin gives a series of the most wonderful and minute contrivances, by
which the visits of insects are utilised for the fertilisation of
orchids—structures so wonderful that nothing could well be more so,
except the attribution of their origin to minute, fortuitous, and
indefinite variations.
“The instances are too numerous and too long to quote, but in his ‘Origin
of Species’ he describes two which must not be passed over. In one
(_coryanthes_) the orchid has its lower lip enlarged into a bucket, above
which stand two water-secreting horns. These latter replenish the
bucket, from which, when half-filled, the water overflows by a spout on
one side. Bees visiting the flower fall into the bucket and crawl out at
the spout. By the peculiar arrangement of the parts of the flower, the
first bee which does so, carries away the pollen mass glued to his back,
and then when he has his next involuntary bath in another flower, as he
crawls out, the pollen attached to him comes in contact with the stigma
of that second flower and fertilises it. In the other example
(_catasetum_), when a bee gnaws a certain part of the flower, he
inevitably touches a long delicate projection which Mr. Darwin calls the
‘antenna.’ ‘This antenna transmits a vibration to a membrane which is
instantly ruptured; this sets free a spring by which the pollen mass is
shot forth like an arrow in the right direction, and adheres by its
viscid extremity to the back of the bee’” (“Genesis of Species,” p. 63).
No one can tell a story so charmingly as Mr. Darwin, but I can no more
believe that all this has come about without design on the part of the
orchid, and a gradual perception of the advantages it is able to take
over the bee, and a righteous determination to enjoy them, than I can
believe that a mousetrap or a steam-engine is the result of the
accumulation of blind minute fortuitous variations in a creature called
man, which creature has never wanted either mousetraps or steam-engines,
but has had a sort of promiscuous tendency to make them, and was
benefited by making them, so that those of the race who had a tendency to
make them survived and left issue, which issue would thus naturally tend
to make more mousetraps and more steam-engines.
Pursuing this idea still further, can we for a moment believe that these
additions to our limbs—for this is what they are—have mainly come about
through the occasional birth of individuals, who, without design on their
own parts, nevertheless made them better or worse, and who, accordingly,
either survived and transmitted their improvement, or perished, they and
their incapacity together?
When I can believe in this, then—and not till then—can I believe in an
origin of species which does not resolve itself mainly into sense of
need, faith, intelligence, and memory. Then, and not till then, can I
believe that such organs as the eye and ear can have arisen in any other
way than as the result of that kind of mental ingenuity, and of moral as
well as physical capacity, without which, till then, I should have
considered such an invention as the steam-engine to be impossible.