The doctrine of evolution according to Herbert Spencer further
considered.
In the last preceding chapter, I have examined Mr. Spencer's chief
objection to the doctrine of special creations when considered in
its general aspects. I now advance to the general aspects of the
evolution hypothesis as applied by this philosopher to the animal
kingdom. I have already suggested the appropriate answer to the
claim that the derivation of the evolution hypothesis is favorable
because it has originated "among the most instructed class and in
these better-instructed times," and that the derivation of the other
hypothesis is unfavorable because "it originated in times of profound
ignorance." On this point it is unnecessary to say more. But there is
a supposed "kindred antithesis" between "the two families of beliefs"
to which these two hypotheses are said respectively to belong; one of
which families "has been dying out," while the other family "has been
multiplying." This brings into view the peculiar philosophical system
of Mr. Spencer, by which he maintains "the unity of Nature," or the
prevalence of a universal law of evolution, as the law which is to be
discerned in remote fields of inquiry, and which "will presently be
recognized as the law of the phenomena which we are here considering,"
namely, the phenomena of animal life. "The discovery that evolution has
gone on, and is going on, in so many departments of Nature, becomes a
reason for believing that there is no department of Nature in which it
does not go on."[69]
In considering this mode of generalization it is important to
distinguish between the phenomena that are observable in those
departments of Nature which include only dead or inanimate matter, and
the phenomena that are peculiar to matter organized into living beings.
Again: it is important to distinguish between phenomena which have been
influenced by human agencies and those which can not have been affected
by the power of man. Another distinction of the greatest consequence
is that which divides the phenomena in question according to their
relation to a moral purpose. In one class of phenomena, a moral purpose
may be plainly discovered as the purpose of an intelligent causing
power, which has chosen a particular means for the accomplishment
of an end. In another class of phenomena, a moral purpose may not
be discoverable as the end for which the existing arrangement of
things was specially designed, and to which that arrangement was an
indispensable means. By classifying the departments of Nature and
observing their phenomena with these discriminations, we shall be
able to judge of the value of Mr. Spencer's philosophical system when
applied to the animal kingdom.
In grouping the departments and their respective phenomena as
departments in which the law of evolution has obtained, and in drawing
from them the sweeping deduction that there is no department in which
this law has not obtained as the _causa causans_, Mr. Spencer does not
appear to have made these necessary discriminations. He specifies the
following remote fields of inquiry, in which he maintains that this law
of evolution is now admitted to be the solution of the phenomena that
lie in those respective fields: First, the solar system, which, as he
asserts, astronomers now consider has been gradually evolved out of
diffused matter.[70] Second, geological discoveries, which show that
the earth has reached its present varied structure through a process of
evolution. Third, society, which has progressed through a corresponding
process of gradual development. "Constitutions are not made, but grow,"
is said to be now a recognized truth among "philosophical politicians,"
and a part of the more general truth that "societies are not made, but
grow." Fourth, languages, which, we are told, are now believed not
to have been artificially or supernaturally formed, but to have been
developed. Finally, the histories of religions, philosophy, science,
the fine arts, and the industrial arts, show, it is said, development
"through as unobtrusive changes as those which the mind of a child
passes on its way to maturity."[71]
It is obvious that in some of these departments neither human agency
nor the human will and choice can have had any influence in producing
the phenomena, while in some of them human agency, will, and choice
have had a vast influence in making the phenomena what they are. That
political constitutions or social institutions are not made, but grow,
is a dogma that is by no means universally true, however wise it may
sound, or with whatever confidence in a paradox it may be asserted by
"some political philosophers." While past events and present exigencies
may have largely shaped some political constitutions, we know that
others have been deliberately modified by a choice that has had more
or less of a free scope, and that sometimes this has amounted to an
arbitrary decision. Languages may or may not have been a direct and
supernatural gift from Heaven, but we know that their structure has
been powerfully influenced by human agencies, when they have come
to be written expressions of thought; for they have then received
expansion by the actual coinage of new words, as well as by new
meanings of old words; and even when they were in the first stages
of a spoken tongue, inflections that were purely arbitrary have been
introduced. So it has been with systems of religion, philosophy, the
fine arts, the mechanic arts, legislation, and jurisprudence. While
in all these departments changes have been going on, which upon a
superficial view appear to indicate a kind of spontaneous development,
when they are analyzed they are seen to have been wholly caused, or
more or less influenced, by the genius, the thought, the discoveries,
the exertions, and the acts of particular individuals who have had the
force to impress themselves upon the age, and thus to make new systems,
new beliefs, new products, new rules of social or political life, new
tastes, and new habits of thinking and acting.
Again: in some of the various orders of phenomena which are found in
these different departments, there is discernible a distinct moral
purpose in the shape which they have been made to assume, and in
others of them there is no moral purpose discoverable, which we can
say required the employment of the particular means to effect the
end. Thus, astronomers can not assign a moral purpose for which the
distribution of the fixed stars was made to be what it is, and which
purpose could not have been answered by some other arrangement. At
the same time, it is easy to see that the solar system was arranged
with reference to the law of universal gravitation, which made this
arrangement of the different bodies essential to the harmonious working
of a great and complex piece of mechanism. The present formation of
the earth may have resulted just as geologists think it has, and yet
they can not say that there was no moral purpose in the division of the
exterior surface of our globe into land and water, seas, continents,
mountains, etc. These are departments of Nature in which man has had no
influence in producing the phenomena. When we turn to those departments
in which man is placed as an actor, we often find an adjustment of
means to an end that is so comprehensive, as well as so plain, that
we may justly conclude it to have been chosen by the creating power,
with the express intent that human agency should be the means by which
certain effects are to be produced. For example: man is eminently
a social animal. Human society is a result of his strong social
propensities. He is placed in it as an actor; and in this arrangement
there is discoverable a moral purpose so plain that we may rightfully
regard the social phenomena of mutual protection and improvement
as proofs that society was ordained as the sphere of man's highest
development on earth.
So that, in reasoning about the phenomena of any of the departments
of Nature as affording indications of the so-called universal law
of evolution, we must not forget the distinction between organized
inanimate and organized animated matter; or the distinction between
those departments in which human will or choice, or the human
intellect, has had no influence in shaping the phenomena, and those
in which they have had great influence; or the distinction between
phenomena in which a special moral purpose can be and those in which
it can not be discovered, as the reason for the existing order of
things. It is especially hazardous to argue that because a spontaneous
development, or a gradual evolution, can be traced in some of the
phenomena of inanimate matter, it therefore must obtain in the animal
kingdom. It is alike hazardous to argue, because there has been what
is called evolution in some departments of Nature over which man has
had no control, that the same law obtains in other departments over
which he has also had no control, or those in which he has had a large
control.
The bearing of these discriminations upon the supposed universality
of the law of evolution may now be seen if we attend to the further
inquiry whether that law obtains throughout all the phenomena of
any one department of Nature as the sole cause of the phenomena in
that department. Take again, for example, the solar system. Suppose
it to be true that the bodies which compose it, the sun and the
planetary spheres, were gradually evolved out of diffused matter. Does
it necessarily follow that their existing arrangements and mutual
relations were not specially designed? That their orbits, their
revolutions, their distances from each other, were not specially
planned? That they were not hung in their respective positions with
an intentional adjustment to the great force of gravitation that was
prevailing throughout the universe? Must we suppose that all this part
of the whole phenomena of the solar system resulted from the operation
of an ungoverned evolution, because the bodies themselves may have been
gradually formed out of diffused matter into their present condition
without being spoken at once into that condition by the fiat of the
Almighty? We can certainly see that the existing arrangements must have
been intentional; and, if intentional, the intention must have taken
effect in the production of the phenomena exhibited by the arrangement,
as any design takes effect in the production of the phenomena which
are open to our observation. The moral purpose evinced by one part of
this arrangement, the alternation of day and night upon the earth,
for example, might have been effected by some other means than the
means which now produce it. But there is the strongest evidence that
a certain means was chosen and intentionally put into operation; and
although we can not tell why that means was preferred, the fact that it
was both designed and preferred makes it a special creation. To suppose
that it was left to be worked out by a process such as the hypothesis
of evolution assumes, by the gradual, fortuitous, and ungoverned
operation of infinitely slow-moving causes, which might have made the
adjustments very different from what they are, is to deprive it of the
element of intentional preference that is proved by its existence.
The hypothesis of evolution, when applied to all the phenomena of the
solar system, relegates one great branch of those phenomena to a realm
from which all special purposes and all direct design are absent, and
confines the explanation of the phenomena to the operation of causes
that might have brought about very different arrangements. That this
supposed process of evolution has, in fact, been followed by the
existing arrangements of the solar system, does not prove, or tend to
prove, that the existing arrangements are solely due to the supposed
method of their production; for we can not leave out the element of
some design, and if there was a design, the very nature of the system
required that the design should be executed by a special creation of a
plan for the mutual relations of the bodies composing it. The bodies
themselves might have been gradually formed out of diffused matter,
floating loosely in the realms of space. The relations of the bodies
to each other required the act of an intelligent will, in the direct
formation of an intentional plan; and that act was an act of special
creation in the same sense in which the structural plan of a species of
animal was a special creation.
Here, then, is one department of Nature in which it is not necessary
and not philosophical to assume that the law of so-called evolution has
been the universal law to which all the phenomena of that department
are to be attributed. If we follow out the same inquiry in other
departments of Nature remote from the animal kingdom, we shall find
reason to adopt the same conclusion in respect to their phenomena.
Thus, let us for a moment contemplate another of the departments
in which inanimate matter is the subject of observation, and in
which human will or intelligence has had no agency in producing the
phenomena, namely, the formation of the present structure of the
earth as it is described by geologists. This is a department in which
the hypothesis of evolution finds perhaps its stronghold. Yet it is
necessary even here to recognize an intentional plan and direct design
in some part of the phenomena. Let us suppose that during the period
required by any of the speculations of geologists, however long, a
mass of matter was gathered in an unformed condition, and gradually
shaped into the present condition of the earth by the action of its
constituent elements upon each other, influenced by the laws of
mechanical forces, of chemical combinations, of light and heat, and
of whatever physical agencies were made to operate in the process of
evolving the mass into the condition in which it has been known to us
for a certain time. Is it a rational conclusion that the intelligent
power which put these forces in operation--an hypothesis with which we
must begin to reason, or leave the origin of both matter and forces to
blind chance--did not guide their operation at all to the intentional
production of the results which we see? The results disclose some
manifest purposes; and although these purposes, or others equally
beneficent, might have been accomplished by different arrangements,
we can see that they have been effected by a certain arrangement of a
specific character. The results have been continents, seas, mountains,
rivers, lakes, formation and distribution of minerals, growth of
forests, and an almost innumerable, and certainly a very varied,
catalogue of phenomena, physical formations, and adaptations. All these
varied results disclose a plan by which this earth became a marvelously
convenient abode for the living creatures that have inhabited or still
inhabit it, especially for man. The formation of this plan was an
intelligent act, if we suppose that any intelligent being projected
the original gathering of the crude primordial matter and subjected it
to the operation of the forces employed to shape it into its present
condition. This plan was an act of special creation, in the same
sense in which the plan of a particular animal organism may have been
a special creation. While, therefore, a process which may be called
evolution may have operated as the agency through which the earth has
reached its present physical condition, the plan of that condition was
certainly not formed by any such process; for it was, if it was the
product of anything, the product of an intelligent will operating in
the production of preconceived results by the exercise of superhuman
and infinite wisdom and foresight.
When we turn to a department in which human influence has largely
or wholly shaped the phenomena, we find numerous special creations
that are not attributable to the operation of any law of development
or evolution such as is supposed to have led to the production of
one species of animal out of another, or out of several previous
species. In short, a survey of all the departments of Nature leads to
the conclusion that while there may be phenomena which are properly
traceable to the operation of the forces of Nature, or to fixed
general systems of production, there is another very large class
of the phenomena which owe their existence to special acts of an
intelligent will, finite or infinite, human or divine, according as
their production required superhuman power or admitted of the efficacy
of man's intervention.
The way is now somewhat cleared for an examination of Mr. Spencer's
application of the law of evolution to the gradual formation of
different species of animals out of one or more previous species,
without any act of special creation intervening anywhere in the series.
We have seen that this alleged law is not of universal force as the
cause of all the phenomena in all the departments of Nature. When
we come to apply it as the hypothesis which is to account for the
existence of different species of animals of very different types, we
must remember that we are dealing with organisms endowed with life,
and, although we can not sufficiently explain what life is, we know
that animated organisms are brought into being by systems of production
that are widely different from the modes in which inanimate matter
may have been or has been made to assume its existing forms. Bearing
this in mind, we come to the arguments and proofs by which Mr. Spencer
maintains the immense superiority of the evolution hypothesis over
that of special creations, in reference to the animal kingdom. It must
be remembered that this is a department in which man can have had no
agency in producing the phenomena, for whatever may have been the
slight variations produced by human interference with the breeding of
animals domesticated from their wild condition, we must investigate the
origin of species as if there had never been any human intervention
in the crossing of breeds, because that origin is to be looked for in
a sphere entirely removed from all human interference. Man himself is
included in the investigation, and we must make that investigation in
reference to a time when he did not exist, or when he did not exist as
we now know him.
One of the favorite methods of Mr. Spencer consists in arraying
difficulties for the believers in special creations, which, he argues,
can not be encountered by their hypothesis, and then arguing that there
are no difficulties in the way of the hypothesis of evolution. His
position shall be stated with all the strength that he gives to it,
and with all the care that I can bestow upon its treatment. He puts
the argument thus: In the animal kingdom individuals come into being
by a process of generation--that is to say, they arise out of other
individuals of the same species. If we contemplate the individuals
of any species, we find an evolution repeated in every one of them by
a uniform process of development, which, in a short space of time,
produces a series of astonishing changes. The seed becomes a tree,
and the tree differs from the seed immeasurably in bulk, structure,
color, form, specific gravity, and chemical composition; so that
no visible resemblance can be pointed out between them. The small,
semi-transparent gelatinous spherule constituting the human ovum
becomes the newly-born child; and this human infant "is so complex in
its structure that a cyclopædia is needed to describe its constituent
parts. The germinal vesicle is so simple that it may be defined in a
line. Nevertheless, a few months suffice to develop the one out of
the other, and that, too, by a series of modifications so small that
were the embryo examined, at successive minutes, even a microscope
would with difficulty disclose any sensible changes. Aided by such
facts, the conception of general evolution may be rendered as definite
a conception as any of our complex conceptions can be rendered. If,
instead of the successive minutes of a child's fœtal life, we take
successive generations of creatures, if we regard the successive
generations as differing from each other no more than the fœtus did in
successive minutes, our imaginations must indeed be feeble if we fail
to realize in thought the evolution of the most complex organism out of
the simplest. If a single cell, under appropriate conditions, becomes
a man in the space of a few years, there can surely be no difficulty
in understanding how, under appropriate conditions, a cell may, in the
course of untold millions of years, give origin to the human race."[72]
Here, then, we have a comparison between what takes place in the
development of the individual animal in the space of a few years,
and what may be supposed to take place in the successive generations
of different creatures through untold millions of years. We turn
then to the proof, direct or indirect, that races of entirely
distinct organisms have resulted from antecedent races by gradual
transformation. Direct proof sufficient to establish the progressive
modifications of antecedent races into other races is not claimed to
exist; yet it is claimed that there are numerous facts of the order
required by the hypothesis which warrant our acceptance of it. These
facts are the alterations of structure which take place in successive
generations of the same species, amounting, in the course of several
generations of the same race, to additions and suppressions of parts.
These changes among the individuals of the same race, comprehended in
what is scientifically called "heredity" and "variation," are exhibited
by the transmission of ancestral peculiarities of structure, by their
occasional suppression in some individuals of the race and their
reappearance in others, and by a difference in the relative sizes of
parts. These variations, arising in successive short intervals of time,
are said to be quite as marked as those which arise in a developing
embryo, and, in fact, they are said to be often much more marked. "The
structural modifications proved to have taken place since organisms
have been observed is not less than the hypothesis demands--bears as
great a ratio to this brief period as the total amount of structural
change seen in the evolution of a complex organism out of a simple germ
bears to the vast period during which living forms have existed on
earth."[73]
The difficulty that is thus prepared for the hypothesis of the special
creation of species may now be stated. There is a professed conception
of the ultimate power which is manifested to us through phenomena.
That conception implies omnipotence and omniscience, and it therefore
implies regularity of method, because uniformity of method is a mark
of strength, whereas irregularity of method is a mark of weakness. "A
persistent process, adapted to all contingencies, implies greater skill
in the achievement of an end than its achievement by the process of
meeting the contingencies as they severally arise." And, therefore,
those who adopt the notion of the special creation of species do, it
is said, in truth impair the professed character of the power to which
they assume that the phenomena of the existence of species are to be
referred, whereas the hypothesis of the evolution of species out of
other species is much more consistent with the professed conception of
the ultimate power.
In this claim of superiority for the evolution hypothesis, the learned
philosopher seems to have been almost oblivious of the fact that he was
dealing with animal organisms in two aspects: first, in regard to the
method by which individuals of the same species come into existence;
and, secondly, in regard to the method by which different species have
come into existence. In the first case, regularity of method is evinced
by the establishment of a uniform process of procreation and gestation.
This process, while retaining throughout the different classes of
animals one fundamental and characteristic method, namely, the union
of the sexes, is widely varied in respect to the time of gestation,
the fœtal development, and the nourishment of the young before and
after birth. There is no difficulty whatever in discovering the great
reason for which this system of the reproduction of individuals was
established. The tie that it makes between parents and offspring, and
more especially the tie between the female parent and the offspring,
was obviously one grand end for which this system of giving existence
to individuals was adopted; and although the instinct which arises
out of it is in some species feeble and almost inactive, it rises
higher and higher in its power and its manifestations in proportion
as the animals rise in the scale of being, until in man it exhibits
its greatest force and its most various effects, producing at last
pride of ancestry, and affecting in various ways the social and even
the political condition of mankind. But how can any corresponding
connection between one race of animals and another, or between
antecedent and subsequent species, be imagined? The sexual impulse
implanted in animals leads to the production of offspring of the same
race. The desire for offspring keeps up the perpetual succession of
individuals, and love of the offspring insures the protection of the
newly born by the most powerful of impulses. But what can be imagined
as an analogous impulse, appetite, or propensity which should lead one
species to strive after the production of another species? Is it said
that the different species are evolved out of one another by a process
in which the conscious desires, the efforts, the aspirations of the
preceding races play no part? This is certainly true, if there was
ever any such process as the evolution of species out of species; and
it follows that, in respect to one great moral purpose of a process,
there is no analogy to be derived from the regularity and uniformity of
the process by which individuals of the same species are multiplied.
Moreover, in regard to the latter process, we know that a barrier has
been set to its operation; for Nature does not now admit of the sexual
union between animals of entirely distinct species, and we have no
reason to believe that it ever did admit of it at any period in the
geological history of the earth.
Still further: In what sense are special creations "irregularities
of method"? In what sense are they "contingencies"? And if they are
"contingencies," how does it imply less skill to suppose that they
have been met as they have severally arisen, than would be implied by
supposing that they have been achieved by a uniform process adapted
to all contingencies? This notion that something is derogated from
the idea of omnipotence and omniscience by the hypothesis that such
a power has acted by special exercises of its creating faculty in
the production of different orders of beings as completed and final
types, instead of allowing or causing them to be successively evolved
out of each other by gradual derivations, is neither logical nor
philosophical. In no proper sense is a method of action an irregular
method unless it was imposed upon the actor by some antecedent
necessity, which compelled him to apply a method which was made uniform
in one case to another case in which the same kind of uniformity
would not be indispensable. The uniformity of the process by which
individuals of the same species are multiplied is a uniformity for that
particular end. The regularity in that case is a regularity that has
its special objects to accomplish. The uniformity and regularity of
a different method of causing different types of organisms to exist,
so long as the object is always effected in the same way, is just as
truly a regularity and uniformity for that case, and just as completely
fulfills the idea of infinite skill. That such creations are specially
made, that they are independently made, and that each is made for a
distinct purpose and also for the complex purposes of a varied class
of organisms, does not render them contingencies arising at random, or
make the method of meeting them an occasional, irregular, spasmodic
device for encountering something unforeseen and unexpected. The very
purposes for which the distinct organisms exist--purposes that are
apparent on a comprehensive survey of their various structures and
modes of life--and the fact that they have come into existence by some
process that was for the production of the ends a uniform and regular
one, whether that process was special creation or evolution, render the
two methods of action equally consistent with the professed conception
of the ultimate power. On the hypothesis of special creations so many
different types of organism as the Creator has seen fit to create have
been made by the exercise of a power remaining uniformly of the same
infinite nature, but varying the products at will for the purposes of
infinite wisdom.
What, again, does the learned author mean by meeting "contingencies"
"as they have severally arisen"? This suggestion of a difficulty for
the believers in special creations seems to imply that the distinct
types of animal organisms arose somehow as necessities outside of the
divine will, and that the Almighty artificer had to devise occasional
methods of meeting successive demands which he did not create. The
hypothesis of special creations does not drive its believers into any
such implications. The several distinct types of animal organisms are
supposed to have arisen in the divine mind as types which the Almighty
saw fit to create for certain purposes, and to have been severally
fashioned as types by his infinite power. They are in no sense
"contingencies" which he had to meet as occasions arising outside of
his infinite will. A human artificer has conceived and executed upon a
novel plan a machine that is distinguishable from all other machines.
He did not create the demand for that machine; the demand has grown
out of the wants of society; and the artificer has met the demand by
his genius and his mechanical skill, which have effected a marked
improvement in the condition of society. In one sense, therefore, he
has met a "contingency," because he has met a demand. But the infinite
Creator, upon the hypothesis of his existence and attributes, does not
meet an external demand; there is no demand upon him; he creates the
occasion; he makes the different organisms to effectuate the infinite
purposes which he also creates; the want and the means of satisfying
the want alike arise in the infinite wisdom and will. Such is the
hypothesis. We may now, therefore, pursue in some further detail the
argument which maintains that this hypothesis is of far inferior
strength to that of evolution, as the method in which the Almighty
power has acted in the production of different animal organisms.
First we have the analogy that is supposed to be afforded by what takes
place in the development of a single cell into a man in the space of
a few years, and an alleged correspondence of development by which
a single cell, in the course of untold millions of years, has given
origin to the human race. Granting any difference of time which this
comparison calls for, and substituting in place of the successive
moments or years of an individual life, from the formation of the
ovum to the fully developed animal, the successive generations of any
imaginable series of animals, the question is not merely what we can
definitely conceive, or how successfully we can construct a theory.
It is whether the supposed analogy will hold; whether we can find
that in the two cases development takes place in the same way or in
a way that is so nearly alike in the two cases as to warrant us in
reasoning from the one to the other. In the case of the development of
the single cell into the mature animal, although we can not, either
before or after birth, detect the changes that are taking place from
minute to minute, the infinitesimal accretions or losses, we know that
there is a perpetual and unbroken connection of life maintained from
the moment when the fœtus is formed to the moment when the mature
animal stands before us. Break this connection anywhere in the process
of development, and life is destroyed; the development is at once
arrested. It is this connection that constitutes, as I presume, what
the learned author calls the "appropriate conditions," in the case of
the production of the individual animal; it is, at all events, the one
grand and indispensable condition to the development of the cell into
the fœtus, of the fœtus into the newly born child, and of the child
into the man. Now, if we are to reason from this case of individual
development to the other case of successive generations of creatures
differing from each other in the same or any other ratio in which
the perfect man differs from the ovum, the fœtus, or the newly born
child, which are all successive stages of one and the same individual
life, we ought to find in the successive generations of the different
creatures some bond of connection, some continuity of lives with lives,
some perpetuation from one organism to another, that will constitute
the "appropriate conditions" for a corresponding development from a
single cell through the successive types of animal life into the human
race. Without such connection, continuity, perpetuation from organism
to organism, shown by some satisfactory proof, we have nothing but a
theory, and a theory that is destitute of the grand conditions that
will alone support the analogy between the two cases. If anywhere in
the supposed chain of successive generations of different animals the
continuity of animal and animal is broken, the hypothesis of special
creations of new organisms must come in: for we must remember that
we are reasoning about animal life, and if the continuity of lives
with one another is interrupted, the series terminates, just as the
series between the ovum, the fœtus, the child, and the man terminates,
at whatever stage it is interrupted by a cause that destroys the
mysterious principle of life. It is therefore absolutely necessary to
look for some proof which will show that in the supposed series of
successive generations of animals out of antecedent types, by whatever
gradations and in whatever space of time we may suppose the process
of evolution to have been worked, there has been a continuity of life
between the different types, a perpetuation of organism from organism,
a connection of lives with lives.
We now come to another supposed analogy, on which great stress is laid
by the evolution school, and especially by Mr. Spencer. Individuals
of the same family are found to be marked by striking peculiarities
of structure, ancestral traits, which appear and disappear and then
appear again, in successive generations. This is obviously a case where
the "appropriate conditions" are all comprehended in the connection
of life with life. When we trace the pedigree of a single man or any
other individual animal back to a remote pair of ancestors, we connect
together in an unbroken chain the successive generations of parents
and offspring. If the chain is anywhere broken, so that direct descent
can not be traced throughout the series, we can not by direct evidence
carry the peculiarities of family traits any further back than the
ancestor or pair of ancestors with which we can find an unbroken
connection of life with life. We do indeed often say in common parlance
that an individual must have a trace of a certain blood in his veins,
because of certain peculiarities of structure, complexion, or other
tokens of descent, even when we can not find a perfect pedigree
which would show where the infusion of the supposed blood came in.
But although it might be allowable, in making out the descent of an
individual man or any other animal, from a certain ancestor or pair of
ancestors, to aid the pedigree by strong family or race resemblance,
even when a link is wanting, it could only be for the purpose of
establishing a pedigree, a connection of lives with lives, that such
collateral evidence could be resorted to. If by direct proof of an
unbroken descent a full pedigree is made out, or if, when some link is
wanting, the collateral proof from strong family or race resemblances
is sufficient to warrant the belief that the link once existed, we
might accept it as a fact that the individual descended from the
supposed ancestors in a direct line, or that some peculiarity of blood
came into his constitution at some point in the descent of individuals
from individuals.[74]
Can we apply this mode of reasoning to the evolution of distinct types
of animals out of antecedent and different types? The very nature of
the descent or derivation that is to be satisfactorily established
requires a connection of lives with lives, just as such a connection is
required in making out the pedigree of an individual animal. We must
construct a pedigree for the different classes or types of animals
through which, by direct or collateral evidence, we can connect the
different organisms together, so as to warrant the belief that by
the ordinary process of generation these animals of widely different
organizations have been successfully developed out of each other, life
from life, organisms from organisms. The hypothesis is, that from a
single cell all the various races and types of animals have in process
of time been gradually formed out of each other, through an ascending
scale, until we reach the human race, whose race pedigree consists of a
series of imperceptible formations, back to the single cell from which
the whole series proceeded. This, we must remember, is not a case of
the evolving production of different forms of inanimate matter, but it
is the case of the evolving production of different forms of animal
life out of other preceding and different forms, by the process of
animal generation.
Of direct evidence of this evolution of species, it can not be said
that we have any which will make it a parallel case with the direct
evidence of the descent of an individual from parents and other
ancestors. We have different animal organisms that are marked by
distinctions which compel us to regard them as separate species, and
there is no known instance in which we can directly trace a production
of one of these distinct species out of another or others by finding
a connection of lives with lives. Even in the vegetable kingdom, with
all the crosses for which Nature has made such wonderful and various
provision, we do not find such occurrences as the production of an oak
out of the seed of an apple, or the production of an orange-tree out of
an acorn. We do not gather grapes of thorns or figs of thistles. There
are barriers set to miscegenation even in the vegetable world, and we
have no direct evidence that at any period in the geological history of
the earth these barriers have been crossed, and very little indirect
evidence to warrant us in believing that they ever have been or ever
will be. In the animal kingdom such barriers are extremely prominent
and certain. We not only have no direct evidence that any one species
of animal was at any period of the earth's history or in any length of
time gradually evolved out of another distinct species, but we know
that the union of the sexes and the production of new individuals can
not take place out of certain limits; that, while Nature will permit
of the crossing of different breeds of the same animal, and so will
admit of very limited variations of structure, she will not admit of
the sexual union of different species, so as to produce individuals
having a union of the different organisms, or a resultant of a third
organism of a different type from any that had preceded it. Is it, for
example, from mere taste or moral feeling that such occurrences as the
sexual union between man and beast have not been known to have produced
a third and different animal? We know that it is because the Almighty
has "fixed his canon" against such a union in the case of man and in
the cases of all the other distinct animal organisms; and to find this
canon we do not need to go to Scripture or revelation, although we may
find it there also.
We are remitted, therefore, to indirect evidence, and in considering
this evidence we have to note that we have nothing but an imaginary
pedigree, or one hypothetically constructed, to which to apply it. In
tracing the pedigree of an individual animal, we have a certain number
of known connections of life with life; and where it becomes necessary
to bridge over a break in the connection so as to carry the line back
to an earlier ancestor, we may perhaps apply the collateral evidence
of family or race resemblance to assist in making the connection with
that particular ancestor a reasonably safe deduction. But in the case
of the hypothetical pedigree which supposes the human race to have been
evolved from a single cell through successive organisms rising higher
and higher in the scale of being, we have no known connections of lives
with lives to which to apply the collateral proofs. The collateral
proofs are not auxiliary evidence; they are the sole evidence; and
unless they are such as to exclude every other reasonable explanation
of the phenomena which they exhibit excepting that of the supposed
evolution, they can not be said to satisfy the rules of rational belief
in the hypothesis to which we apply them.
What, then, is the indirect and collateral evidence? It consists, as
we have already seen, of two principal classes of phenomena: first,
resemblances of fœtal development which are found on comparing the
fœtal growth of different species of animals; second, resemblances in
the structure of different species of animals after birth and maturity.
These various resemblances are supposed to constitute proof of descent
from a common stock, which may be carried back in the series as far as
the resemblance can be carried, at whatever point that may be. Thus,
in comparing all the vertebrata, we find certain marked peculiarities
of structure common to the whole class: the deduction is, that all the
vertebrate animals came from a common stock. In comparing all the
mammalia, we find certain marked peculiarities of structure common
to the whole class: the deduction is that all the mammalia came from
a common stock. Going still further back in the supposed series, we
come to the amphibians, as the supposed common stock from which the
vertebrate and mammalian land animals were derived; and, comparing the
different classes of the amphibians, we find certain resemblances which
point to the fish inhabitants of the water as their common stock; and
then we trace the more highly organized fishes through the more lowly
organized back to the aquatic worm, which may itself be supposed to
have been developed out of a single cell.[75]
The resemblances of structure, wherever we make the comparison
between different species, are referable to an ideal plan of animal
construction, followed throughout a class of animals, and adjusted to
their peculiar differences which distinguish one species from another,
just as in the vegetable world there is an ideal plan of construction
of trees followed throughout a class of plants, and adjusted to the
peculiar differences which distinguish one kind of tree from another.
As between man and the monkey, or between man and the horse, or the
seal, or the bat, or the bird, there are certain resemblances in the
structure of the skeleton, which indicate an identity of plan, although
varied in its adjustments to the distinguishing structure of each
separate species of animal. In a former chapter, I have shown why the
adoption of an ideal plan of a general character is consistent with
what I have called the "economy of Nature" in the special creation of
different species. On a careful revision of the subject, I can see
no reason to change the expression, or to modify the idea which it
was intended to convey, and which I will here repeat. It is entirely
consistent with the conception of an infinite and all-wise creating
power, to suppose that in the formation of a large class of organisms,
all the constructive power that was needed for the formation of a
general plan was exercised throughout the class, and that there was
super added the exercise of all the power of variation that was needful
to produce distinct species. Repetition of the same general plan of
construction is certainly no mark of inferiority of original power,
if accompanied by adaptations to new and further conditions. It is
a proof that in one direction all the necessary power was used, and
no more, and that in producing the distinct organisms the necessary
amount of further power was also used. If we follow the resemblances of
structure that may be traced through all the animals of a varied class,
we shall find that they may be referred, as a rational and consistent
hypothesis, to this method of giving to each animal its characteristic
formation. If this is a rational hypothesis, it is so because it is
consistent with all the observable phenomena; and consequently, the
opposite hypothesis that all these phenomena of resemblances and
differences are due to the law of evolution does not exclude every
other explanation of their existence.
To apply this now to one of the comparisons on which great stress
is laid--the comparison between the brain of man and that of the
ape. Two questions arise in this comparison: 1. Do the resemblances
necessarily show that these two animals came from a common stock? 2.
Do the resemblances necessarily show that man was descended from some
ape through intermediate animals by gradual transformations? And, when
I ask whether the comparison necessarily leads to these conclusions,
I mean to ask whether the resemblances point so strongly to the
conclusions that they must rationally be held to exclude every other
hypothesis.
Prof. Huxley furnished to Mr. Darwin a very learned note, in which he
stated the results of all that is now known concerning the resemblances
and differences in the structure and the development of the brain in
man and the apes. The differences may be laid aside in the present
discussion, because it is not necessary, for my present purpose, to
found anything upon them. But the resemblances, just as they are stated
by the eminent anatomist, without regard to controverted details,
are the important facts to be considered. The substance of the whole
comparison is that the cerebral hemispheres in man and the higher apes
are disposed after the very same pattern in him as in them; that every
principal "gyrus" and "sulcus" of a chimpanzee's brain is clearly
represented in that of a man, so that the terminology which applies
to one answers for the other; that there is no dispute as to the
resemblance in fundamental character between the ape's brain and man's;
and that even the details of the arrangement of the "gyri" and "sulci"
of the cerebral hemispheres present a wonderfully close similarity
between the chimpanzee, orang, and man.[76] These are said to be
the result of a comparison of the adult brain of man and the higher
apes; and, although it is claimed by some anatomists that there are
fundamental differences in the mode of their development which point
to a difference of origin, this is denied by Huxley, who maintains
that there is a fundamental agreement in the development of the brain
in man and apes. His views of the facts for the purpose of the present
inquiry may be accepted without controversy, not only because he is an
authority whose statements of facts I am not disposed to dispute, but
because it is not necessary to dispute them. What, then, do they show?
They show that there are animals known as apes and animals known as
men, whose brains are found to be fundamentally constructed upon the
same general plan, with strong resemblances throughout the different
parts of the organ; and the first question is, Do these resemblances
show that the two animals came from a common stock? Upon the theory
that man has resulted from the gradual modifications of the same form
as that from which the apes have sprung, the resemblances in the
structure of their respective brains are claimed as having a tendency
to show that there was an animal which preceded both of them, and which
was their common ancestor, in the same sense in which an individual
progenitor was the common ancestor of two other individuals, whether
one of these two individuals was or was not descended from the other in
a direct line. On the other hand, upon the hypothesis of the special
creation of the ape as one animal, and the special creation of man as
another animal, there was no common stock from which the two animals
have been derived, and the resemblances of their brains point to the
adoption of a general plan of construction for that organ, or its
construction upon the same model, and the adaptation of that model to
the other parts of the structure, and the purposes of the existence of
each of the two animals. Without again repeating the argument which
shows that the latter hypothesis is perfectly consistent with the
professed conception of the infinite power, I will now inquire whether,
on the former hypothesis, we have anything to which we can apply the
evidence of resemblance as a collateral aid in reaching the conclusion
that these two animals were derived from a common progenitor, or from
some antecedent animal whose brain and other parts of the structure
became modified into theirs by numerous intermediate gradations.
Between the higher apes, or between any of the apes and any known
antecedent and different animal, no naturalist has discovered the
intermediate link or links. Darwin supposes that there was some
one extremely ancient progenitor from which proceeded the two main
divisions of the _Simiadæ_--namely, the Catarrhine and Platyrhine
monkeys, with their sub-groups. This extremely ancient progenitor is
nothing but a scientific hypothesis; or, to use a legal phrase, it
had nothing but a constructive existence. It is necessary to believe
in the principle of evolution, in order to work out the hypothesis
of this creature from which the two great stems of the _Simiadæ_ are
supposed to have proceeded. Here, then, we have the case of a pedigree
or succession of animal races, the _propositum_ of which has no known
existence. Next we have two known divisions of the _Simiadæ_, or
monkeys; but, between them and their imaginary common progenitor, we
have no known intermediate animals constituting the gradations of
structure from the progenitor to the descendants. The whole chain has
to be made out by tracing resemblances among the animals of a certain
class that are known, then applying these resemblances to the supposed
divergencies from the structure of a supposed progenitor, and then
drawing the conclusion that there was such a progenitor. It may be
submitted to the common sense of mankind, whether this is a state of
facts which will warrant scientists or philosophers in using toward
those who do not accept their theory quite so much of the _de haut en
bas_ style of remark as we find in the writings of Mr. Spencer.[77]
If the researches of geologists had ever discovered any remains of
an animal that would fulfill the requirements, and thus stand as the
progenitor of the _Simiadæ_. By the case would correspond to that of a
known individual from whom we undertake to trace the descent of another
individual through many intermediates; and in such a case strong family
resemblances of various kinds might possibly afford some aid in making
out the pedigree as a reliable conclusion. But there is no means of
connecting the Old World and the New World apes with any but an unknown
and imaginary, progenitor. Darwin himself frankly tells us that "the
early progenitor of the whole Simian stock, including man," is an
undiscovered animal, which may not have been identical with, or may not
even have closely resembled, any existing ape or monkey.[78]
Passing from the supposed common progenitor to the resemblances
between the brain of the higher apes and the brain of man, we come to
the question whether these resemblances show that man was descended
from any of the Simian stock through intermediate animals by gradual
transformation. Here the case is in one respect different; for the
animals that are to be compared are known, and their respective brains
have been subjected to close anatomical scrutiny. This part of the
process of evolution begins from one true species, the ape, and ends
in another true species, the man. We are unable to trace the man and
the ape to a common progenitor race; but we find the ape possessed of
a brain which strongly resembles man's. I have searched diligently in
the writings of naturalists for a sound reason which ought rationally
to exclude the hypothesis that the brain of the ape was formed upon
the same ideal plan as the brain of man, each animal being a distinct
species and separately created. Anatomical comparison of the two
brains shows that, whether they were separately planned upon the same
general model, or the one was derived from the other by a process of
gradual transformation through successive intermediate animals, the
resemblances are consistent with either hypothesis. We are remitted,
therefore, to an inquiry for the evidence which will establish the
existence of a race or races of animals through whom there descended
to man the peculiar structure of brain found in one of the classes of
apes--namely, the Catarrhine or Old World monkeys. If such intermediate
races could be found, their existence at any period anterior to the
period of man's appearance on earth would have some tendency to
show that man was descended from one of the families of apes, and
this tendency would become stronger in proportion to the number of
successive links in the family chain that could be made out. But not
one of these links is known to have existed. There is an assumption
that man, "from a genealogical point of view, belongs to the Catarrhine
or Old World stock" of monkeys; and this assumption is claimed to be
supported by the fact that the character of his brain is fundamentally
the same as theirs.
A brain is an organ which, upon the hypothesis of an independent
creation of distinct species of animals, would be expected to be found
in very numerous species, although they might differ widely from
each other. In all the vertebrate animals this organ is the one from
which, by its connection with the spinal chord, the central portion
of the nervous system, that system descends through the arches of
the vertebræ, and thence radiates to the various other organs of
the body. The brain is the central seat of sensation, to which are
transmitted, along certain nerves, the impressions produced upon or
arising in the other organs; and it is the source from which voluntary
activity is transmitted along other nerves to organs and muscles that
are subjected to a power of movement from within. The office which
such an organ performs in a complex piece of animal mechanism is
therefore the same in all the vertebrate animals in which it is found;
and it would necessarily be found to be constructed upon the same
uniform plan, and with just the degree of uniformity and adaptation
which would fit it to perform its office in the particular species
of animal to which it might be given. In point of fact, we find this
office of the brain performed in all the vertebrate animals upon the
same uniform plan, with the necessary adaptations to the various
structures of the different animals. Resemblances, therefore, in the
convolutions of different parts of this organ, as found in different
vertebrate animals, however close they may be, prove nothing more than
the adoption of a general plan for the production of objects common
to the whole class of the vertebrate animals; and unless we can find
other and independent proof that one species was descended from another
by connection of lives with lives through successive generations,
the hypothesis of special creations of the different species is not
excluded by the facts.
Let us now further examine the supposed kinship of man with the
monkey, as evidenced by the similarity of the structure of the
brains of the two animals, in reference to the supposed process of
evolution as the means of accounting for the origin of two species
so essentially distinct. How has it happened that different species
have become completed and final types, transmitting, after they have
become completed, one and the same type, by the ordinary process of
generation, and not admitting of the sexual union with any other
distinct species? On the theory of the evolution of animal out of
animal, we must suppose that at some time the secondary causes of
natural and sexual selection have done their work. It ends in the
production of a species which thereafter remains one and the same
animal, and Nature has established a barrier to any sexual union with
any other species. If we give the rein to our imaginations, and, taking
the process of evolution as it is described to us, suppose that in the
long course of countless ages the struggle for existence among very
numerous individuals has led to gradual transformations of structure
which the sexual selection has transmitted to offspring, and so a new
animal has at length been formed through the successive "survivals of
the fittest," we reach an animal of a new species, and that species,
under no circumstances, produces any type but its own, so far as we
have any means of knowledge. All the knowledge respecting the ape that
has been accumulated shows only that this species of animal, since it
became a completed type, has procreated its own type and no other.
Whatever struggle for existence the individuals of this type have had
to undergo, whatever modifications of structure or habits of life the
survival of the fittest individuals of this type may have produced
from the earliest imaginable period until the present time, the fact
remains that this species of animal is a completed and final product.
At the same time we have another completed and final type of animal
known as man, which, so long as he has been known at all, is a distinct
and peculiar species. Between the brain of this animal and the brain
of the other we find certain strong resemblances. In each of them
this organ is a structure performing the same office in the animal
mechanism, with adaptations peculiar to the varying structure of each
of them. In order to justify the conclusion that the one animal is a
modified descendant from the other, so as to exclude the hypothesis
that the resemblances of any one or of all of their respective organs
was a result of the adoption of a general plan in special creations of
distinct species, we ought to find some instance or instances in which
the completed animal called the ape has been developed into an animal
approaching more nearly to man than the man, as he is first known to
us, approached to the first ape that is known to us. Without such
intermediate connections, the analogy of the descent of individuals
from other individuals of the same species will not hold. There is
nothing left but resemblances of structure in one or more organs, which
are just as consistent with the hypothesis of special creations as with
that of evolution. Strong resemblances of structure and in the offices
of different organs may be found between man and the horse, but upon
no theory of evolution has it been suggested that man is descended
from the horse, or from any other animal to which he bears more or
less resemblance, excepting the monkey; and it is quite possible that
naturalists have been led unconsciously to make this exception by
external resemblances of the monkey and the man, by the imitative power
of the inferior animal when it comes in contact with man, and by some
of its habits when found in its wild and native haunts.
FOOTNOTES:
[69] "Biology," i, pp. 346-348 _et seq._
[70] Concerning the nebular hypothesis, and what astronomers now
consider, see _post._
[71] "Biology," i.
[72] "Biology," i, pp. 349, 350.
[73] "Biology," i, p. 351. I am not quite sure that I understand
what Mr. Spencer means by "direct" proof. In the passage immediately
following the sentence last quoted, he speaks of "the kind and
quantity of _direct evidence_ that all organic beings have gradually
arisen," etc., whereas, in a previous passage, he had admitted that
the facts at present assignable in _direct_ proof of this hypothesis
are insufficient. I presume he meant insufficient in number. (Compare
"Biology," i, pp. 351 and 352). Now, I should say that _direct_ proof
of the hypothesis that all animal organisms have arisen successively
out of one another would require more or less positive evidence of
such occurrences; and that the proof which is afforded by what has
taken place within the limits of a single species in the course of
successive generations would be _indirect_ evidence of what may have
taken place in the evolution of different species, because it requires
the aid of analogy to connect the two. I am not aware that there is
supposed to be any proof of the evolution of species out of species,
excepting that which is derived from what has taken place in single
races in the development of the ovum into the infant, the development
of the infant into the mature animal, and the limited varieties of
structure appearing among individuals of the same race. As I go on
through the examination of Mr. Spencer's argument, it will appear
whether there are grounds for regarding this kind of reasoning as
satisfactory or the reverse.
[74] I have stated here, in reference to the pedigree of an
individual, a far more liberal rule of evidence than would probably be
allowed in courts of justice, where anything of value was depending
upon the establishment of a descent from a certain ancestor. But I
have purposely suggested the broadest rule that can be applied to
family or race resemblances as a means of aiding a pedigree in popular
determination or in a _judicium rusticum_. For example, suppose that
there were persons now living in this country who trace their descent
from the English husband of Pocahontas, the daughter of an Indian
chief, and from her. They bear, we will suppose, the family name of
the Englishman whom she is known to have married, and perhaps one of
them bears very strong resemblance to the Indian race in features,
complexion, and hair. In a judicial trial of this person's supposed
pedigree I do not suppose that these resemblances, if they constituted
his sole evidence, together with the name of Rolfe which he bears, and
which a certain number of his ancestors may have borne before him,
would be received as evidence of his descent from the Indian girl
whose name was Pocahontas, and who married an Englishman of the name
of Rolfe more than two centuries ago. It would be necessary to make
some proof of the whole pedigree by the kind of evidence which the law
admits in such cases, and then the resemblances of the individual to
the Indian race might possibly be received as confirmatory proof, in
aid of the proof derived from the family name of Pocahontas's English
husband, from reputation, written or oral declarations of deceased
witnesses, family documents, ancient gravestones, and the like. In
popular judgment most persons would be apt to accept the family name
of Rolfe and the apparent trace of Indian blood as sufficient proof of
the descent of the individual from the Indian girl who married John
Rolfe. But in a court of justice these facts would go for nothing
without some independent proof of the pedigree.
[75] See the table of the Darwinian pedigree of man, _ante_. Any
other mode of arranging the order of evolution that will admit of the
application of the steps of supposed development to what is known of
the animal kingdom, will equally serve to illustrate the theory.
[76] Darwin's "Descent of Man," Prof. Huxley's note, p. 199 _et seq._
[77] Mr. Spencer observes that the hypothesis of special creations is
one "which formulates absolute ignorance into a semblance of positive
knowledge...." Thus, however regarded, the hypothesis of special
creations turns out to be worthless--worthless by its derivation;
worthless in its intrinsic incoherence; worthless as absolutely
without evidence; worthless as not satisfying a moral want. "We must
therefore consider it as counting for nothing, in opposition to any
other hypothesis respecting the origin of organic beings." There is a
great deal more in the same tone. (See "Biology," i, pp. 344, 345, and
_passim_ throughout Chapters II and III of Part III of that work.) Mr.
Darwin, who is sufficiently positive, is much more moderate, and in my
opinion a much better reasoner, although I can not subscribe to his
reasoning or his conclusions. A rather irreverent naval officer of my
acquaintance once extolled a doctrinal sermon, which he had just heard
preached by a Unitarian clergyman, in this fashion: "I tell you what,
sir, the preacher did not leave the Trinity a leg to stand upon."
Probably some of Mr. Spencer's readers think that he has equally
demolished the doctrine of special creations.
[78] "Descent of Man," p. 155.