the individual brick and bolt and girder, so the evolution of a biological
association begins with the unitary organisms consisting of single cells,
like _Amoeba_. We have had occasion to discuss this animal many times
in our previous studies of one or another aspect of evolution, and once
again we must return to it in order to reëstablish certain points that are
of fundamental importance for our present purposes. Within the limits of
its simple body, _Amoeba_ performs the several tasks which nature
demands a living thing shall do; it feeds and respires and moves,
continually utilizing matter and energy obtained from the environment for
the reconstruction of its substance and replenishment of its vital powers;
it coördinates the activities of its simple body, and by its reflex
responses to environmental influences it maintains its adjustment to the
external conditions of life. The animal does all of these things with a
purely individual benefit, namely, the prolongation of its own life. While
it is performing these individual tasks, it does not concern itself with
anything else but its own welfare; the interests of other living things
are not involved in any way, excepting in the case of other organisms that
may serve the animal as food. _Amoeba_, like every other living thing,
if it is to exist, must unconsciously obey the first great commandment of
nature,--"_Preserve thyself_."
But its life is incomplete if it stops with the furtherance of aims that
we may call purely selfish. Nature also demands that an _Amoeba_, again
like every other living thing, shall perpetuate its kind. The mode by
which it reproduces is ordinarily quite simple; the animal grows to a
certain bulk and then it divides into two masses of protoplasm, each of
which receives a portion of the mother nucleus. Sometimes by a peculiar
process it breaks up into numerous small fragments called spores, which
also receive portions of the parent nucleus. The most striking feature in
both kinds of reproduction in _Amoeba_ is the complete destruction of
the individual parent that exists before the act and does not afterwards.
It is quite true that every part of the mother animal passes over into one
or another of its products, but it is equally true that no one of these
products is by itself the original individual. So even the simplest animal
we know performs a task that is not only useless to itself, but is
completely destructive of itself, for nature's greater purpose of
preserving the race. We can readily see why this must be so; there is no
place in the world for a species whose members put individual well-being
above the welfare of the race, for which the production of new generations
is essential, even though the satisfaction of this demand should
necessitate the sacrifice of the parent organism. We might hesitate to use
the word "altruistic" in describing the self-destructive reproductive act
of an _Amoeba_, because this word connotes some degree of consciousness
of the existence of other than personal interests, and of the welfare of
different individuals. There is no reason to believe that such conscious
recognition of any natural duties is possible in the case of so low an
organism. But the fact remains that the result worked out by nature is the
same as though there were a definite understanding of real duties. Even
this unitary organism, then, acts mechanically so as to fulfil two primal
obligations, first _to itself_, through activities with individual benefit
as the result, and _to the race_ by the act of reproduction which closes
its individual existence and inaugurates a new generation.
The life of this example, representing the whole series of one-celled
organisms, is almost infinitely simpler than that of a member of a human
community, yet it reveals the beginnings of certain characteristics of the
latter. Here, it is true, the natural obligations in question are not like
those which are ordinarily denoted social, but it is equally true that
even in this most elementary instance a living thing does not live unto
itself alone. It is easy to see the value to the species as a whole of
obedience to the second great law--"_Preserve thy kind_." But a little
further thought makes it plain that even the performance of acts in
compliance with the first mandate--"_preserve thyself_"--are not purely
selfish, although their immediate value is realized as individual benefit.
Surely an organism that failed to live an efficient individual life would
be ineffective in reproduction, so that from one point of view everything
an animal does is tributary to the culminating act performed for the
larger good of the life of the whole species. It is a nice balance that
nature has worked out in _Amoeba_, as well as in all other cases,
between the personal life of the individual, complete only when the final
process of multiplication supervenes, and this process itself, which
demands an efficient performance, even though this is destructive of the
performer.
Before passing to the next members of the series, which reveal additional
principles more truly social in the human sense, let us pause to note that
already we have found certain natural criteria that belong in the
department of ethics. Even in the case of the biological unit like
_Amoeba_, which is entirely solitary and unrelated to other individuals
of its kind excepting in so far as it is a link in the chain of successive
generations, any vital activity can be called good or bad, right or wrong.
Nature judges an act good and right if it tends to preserve the animal and
the species; an act is wrong and evil if it is biologically destructive of
the animal or if it interferes with the perpetuation of its kind. Again it
must be pointed out that these terms are human words, employed for the
complex conceptions that belong alone to retrospective and contemplative
human consciousness to most of us they seem to imply the existence of some
absolute standard or ideal by which a given act may be tested to see if it
is right or the opposite.
If human ethics is truly unrelated to beginnings found in lower nature,
something that has arisen by itself from supernature, then we must not use
the terms in question except by way of analogy. If, however, nature has
been continuous in the working out of every department of human life and
human thought through evolution, then the criteria of the righteousness of
the acts performed even by an _Amoeba_ may be found to be basic and
fundamental for ethical systems of whatever human race or time. This
subject remains to be discussed in the final chapter, but it must be clear
that we cannot survey the evolutionary process by which social systems
have come into being without dealing at the same time with the origin and
growth of ethical conduct as such.
* * * * *
Without leaving the group of one-celled animals typified by _Amoeba_, we
find colonies of the most elementary biological nature, where other
natural obligations are added to the two of greatest importance. Some
species of the bell-animalcule, _Vorticella_, provide characteristic
examples of these primitive compound protozoa. Here the assemblage is made
up of one-celled individuals essentially similar to one another in
structure and in physiological activities; in the latter respect each one
of them is like _Amoeba_ as well. They may remain together for a longer
or shorter period, or during their whole existence until the time of
reproduction. Like the solitary protozoön, each member leads a complete
life in and by itself, equivalent to that of every biological unit. It
obeys the two great laws already laid down, but in addition it seems to be
required to remain with the others for some mutual good. The biological
value of the association which imposes this additional obligation may be
found perhaps in the fact that a large group is not so readily eaten by an
enemy as an individual cell; but it is clearer that the process of
reproduction, which consists of the fusion of small "gametes," or
nucleated fragments produced by diverse or similar parents, must be
greatly facilitated by the occurrence of gamete-forming individuals in one
and the same colony. "_To remain together_" is the new duty imposed by
nature for the good of all and for the welfare of each member of the
group. Some biological advantage accrues to the several components, just
as the banding of wolves enables the pack to accomplish something which
the single wolf is unable to do, although in the latter case it is not so
much a reproductive alliance that is formed as an offensive and defensive
union.
One step higher in the scale stands the plant-form called _Volvox_, near
the border-line between the one-celled and the many-celled organisms. This
aquatic type, about the size of the head of an ordinary pin, is a hollow
spherical colony, with a wall composed of closely set cellular components.
These elements are not all alike, as in the case of colonial protozoa like
_Vorticella_, for they fall into two classes which are distinguished by
certain structural and functional characteristics. Most of them are simple
feeding individuals which absorb nourishment for themselves primarily, but
they pass on their surplus supplies to less favored neighbors if occasion
demands. The other members begin life like the first-named, but later they
become specialized to serve as reproductive individuals solely. Every
member of the colony must obey the first precept of nature, otherwise it
would be unable to play its part in the life of the whole community. But
the discharge of the second natural obligation, namely to preserve the
race, is here assigned to some, and to some only, of the whole group of
cell individuals. It follows therefore that the division of the tasks
necessary for the maintenance of a complete biological individual, and the
differentiation of the members of the group into two kinds, leads to the
establishment of an individuality of a higher order than the cell. Neither
the purely nutritive nor the reproducing member is complete in itself; the
two kinds must be combined to make a perfect organism. The life of any
member can be selfish no longer, for if it is to exist itself, it must
help others for the mutual advantage of all. A clear social relation is
thus established; and the reflex conduct of the units of a _Volvox_ colony
can be justly denoted altruistic, even though in this case, as before,
there can be no conscious recognition of the reasons why mutual interests
are best served by what is actually done.
One of the most interesting and significant aspects of the life-history of
_Volvox_ is the appearance for the first time of biological death. More
elementary organisms are immortal potentially even if not actually, for
every portion of the body is capable of passing over into an animal of a
succeeding generation. But in _Volvox_ a division of labor has been
effected of such a nature that most of the components discharge the tasks
of individual value, and with the performance of these they die. Only the
reproductive members are immortal in the sense that _Amoeba_ is, for
they only have a place in the chain of consecutive generations of _Volvox_
colonies. From the standpoint of the nutritive individual it is better to
be relieved of the reproductive task in order that there may be no
interruption of its specialized activities for the good of all, but the
entailed mortality is certainly disadvantageous to it. It is the higher
interest of the colony as a whole that supersedes the welfare of the parts
taken singly, and this larger welfare is safeguarded by a differentiation
worked out by natural evolution which results in the assignment of
personal and racial duties to different individuals, at the cost
ultimately of the lives of the former.
We now reach the realm of the true many-celled animals, or Metazoa, where
the biological units are combined to form an organic association
displaying many more resemblances to a human society. The freshwater polyp
_Hydra_, like the foregoing illustrations, is one whose structure has
already been discussed in the earlier chapters, but now we may use it for
an analysis of another series of biological phenomena. Its sac-like body
consists of two cell-layers; the outer one is concerned primarily with
offense and defense, while the inner layer is made up of digesting or
nutritive elements. The essential cells concerned solely with reproduction
lie below the outer sheet. Comparing this animal with an association like
_Volvox_, we discover the same differentiation into immortal germ-elements
and mortal cells, concerned respectively with the _Hydra's_ racial
existence and with its individual life; but far-reaching changes have come
about in the biological relationships of the second class of cells. In
describing the new phenomena it is absolutely necessary to employ the
terms of human social organization, because the _Hydra's_ body is a true
colony of diverse cells in exactly the same sense that a nation is a body
of human beings with more or less dissimilar social functions.
To begin with the differentiation into ectoderm and endoderm, the organism
is comparable to a human community made up of military and agricultural
classes. The cells of the former group protect themselves and the feeding
elements also, while the units of the second defenseless type devote
themselves to the task of provisioning the whole community, giving
supplies of food to the defenders in exchange for the protection they
afford; each kind needs the other, and each performs some distinctive task
for the other as well as for itself. But the parallel thus drawn need not
stop here. In the case of the outer layer, the cells are mostly flat
covering elements that are the first to be torn off and injured when the
animal is attacked. Scattered about among them are sense-cells standing
like sentinels with delicate upright processes which receive stimuli from
without the sense-cells transmit impulses to the network of nerve-cells
below, which is a counterpart of the signal corps of an army, keeping all
parts of the whole organization in communication with one another. Most
wonderful of all are the stinging-cells of the outer layer; these produce
a flask-shaped, poisoned bomb which is discharged by the convulsive
contraction of the cell itself so as to stun and injure the enemy or prey.
The bomb-throwing cells die immediately after they have ejected their
missiles; like soldiers participating in a forlorn hope, they sacrifice
their lives in one supreme effort of service to the cell-community of
which they are members.
These and similar facts prove conclusively that _Hydra_ is a true
community even in the human sense, and that the laws of biological
association are established at a point far below the level of the insects.
The individuality of the unit is still maintained, and each cell must
guard its own interests to a certain degree, but the original independence
of the unit has become so altered by differentiation and division of labor
that a close interdependent relation has come about. The complete
individual is now the _whole_ aggregate; it is the entire _Hydra_ itself
which must obey the primary commands of nature to live efficiently and to
perpetuate its kind. True it is that the life of the higher individual is
the sum total of the activities performed by its constituent cells, but no
one of the varied specialized elements is biologically perfect by itself
or equivalent to the whole. And, as we have seen, the welfare of the
complete animal takes precedence over that of any one of its parts, just
as the existence of a nation may be preserved only by the death of
soldiers warring for its honor and life.
If, now, we should pass on to the more complex organisms like worms and
insects and vertebrates, and should disregard the communal relations of
some of these animals, each individual proves to be like _Hydra_ as
regards the principles underlying its make-up and workings. A single bee,
like a man, is a definitely constituted aggregate of cells, differing as a
whole from _Hydra_ only in the _degree of differentiation_ exhibited by
its constituent elements. Instead of a loose network of nerve-cells there
is the far more complex nervous system whose evolution has been outlined
in the sixth chapter. The blood-vascular and respiratory and excretory
systems have become well organized, in response, so to speak, to the
demands on the part of the nervous and alimentary organs that they may be
relieved of the tasks of circulation and respiration and the discharge of
ash-wastes. Therefore the cells which make up an insect and a man are more
diverse, they have more varied interrelationships, and they are far more
interdependent then in the case of the components of _Hydra_. Yet all the
many-celled organisms that we are so accustomed to regard as individuals
are really communities, demonstrating the existence and partial antithesis
of the great laws of egoism and altruism, which are traceable even down to
_Amoeba_ and its like.
So much has been made of the lower kinds of cell-associations because the
mind of the layman is unconsciously imbued with the idea that human
society is a new thing,--an idea which we now see it is necessary to
discard at the outset. Indeed, the cell-association of the _Hydra_ and
insect type is a more compact and a more stable kind of community than any
group of human individuals worked out by nature toward the present end of
the whole scheme of evolution. That is to say, the subordination of
cell-interest to cell-group welfare, while it must not go so far as to
render the unit incapable of doing its work, is sufficiently advanced to
make uncontrolled individualism impossible. Let any class of _Hydra's_
cells, such as the nerve or muscle network, assume to exercise a selfish
preeminence or to conduct a "strike," the other classes, like the feeding
cells, would not be properly served and they would be unable in
consequence to work efficiently for the strikers. The immediate result
would be suicidal, for the selfish nerve-class would inevitably suffer
through the downfall of the whole social fabric. It is a nicely adjusted
equilibrium that is established, where the "equal rights" of all the
diverse cells consist in freedom to play a special part in the life of the
group, serving other individuals in return for their service. The Golden
Rule is a natural law as old as nature; for even in _Hydra's_ life,
unconscious discharge of duties to the race, and hence to others, is
obligatory. And all these low types of organic associations evolved ages
before the rules of human social order were vaguely recognized by the
reflective self-consciousness of man, to be formulated as the science of
ethics.
The evolution of the wonderfully varied societies found among insects
begins with the solitary insect itself, just as this, viewed as a
cell-community, originates from one-celled beginnings like _Amoeba_
through progressive evolution in time. The similarity between social
insects and human associations is clearer than in the case of a comparison
between an example from either group and a cell-community, because the
higher forms lack the organic contact of the components which is so
prominent a feature in the lower instance. The social bonds are looser and
they allow a freer play of the constituents; but nevertheless the same laws
that control the activities of the cells making up what we now take as the
individual element, command obedience on the part of the interrelated
members of an insect community with equal strictness.
A butterfly or a moth is primarily egoistic and unsocial in the ordinary
sense during its entire life-history, until the final reproductive act
which has a value to the species. The caterpillar larva devotes all of its
energies to feeding and growing, unconcerned with the final duties of the
moth with which it is connected just as the indifferent unit of a young
_Volvox_ colony is related to a reproducing member of the full-grown
organism. Now and then, it is true, species like the so-called tent
caterpillar are met with where numerous larvæ spin silken communal nests
to which they retire at night and in which they remain to molt. The pupa,
like the larva, is individualistic and employs its time in producing the
final adult form. The mature individual, however, is constructed almost
solely for the greater purpose of perpetuating the species. Indeed the
larger silkworm moths do not and cannot feed, and their value is only that
of a device for keeping the race established. Adult may-flies live only a
few minutes, just long enough to provide for the fertilization and
deposition of the eggs, although to prepare for these acts the young
individuals must have toiled for months; the preparatory time may amount
to many years in such a case as the seventeen-year locust. But nature is
satisfied, as long as the organic mechanisms obey her double commandment,
"Live and grow so as to multiply." Like an _Amoeba_, the solitary insect
must be egoistic at first, in order to be altruistic in a racial sense in
its last days.
Wasps, bees, and ants provide many familiar examples of colonial
organizations that become all the more marvelous on closer acquaintance,
on account of their resemblances to human associations on the one hand,
and to cell-associations on the other. Their illustrative beauty is
enhanced by their wide variety, for they grade from counterparts of highly
civilized men down to a savage among insects, such as the strictly
solitary digger-wasp, whose instincts served to exemplify the insect type
of "mentality" in the discussions of the preceding chapter.
The true communities founded by wasps and hornets must be assigned to a
low grade in the scale because they originate during a single season and
break up at its end; for this very reason the wasp community is intensely
interesting to the student of comparative social evolution. In the spring
a solitary female emerges from the crevice where she has hibernated and
resumes active life; she feeds for a time to renew her strength and then
she constructs a simple nest of mud or masticated wood-pulp. In the first
few cells of this nest she deposits her eggs, and when they hatch she
herself provides the larvæ with food, but still continues to enlarge the
house and to produce more eggs. Thus during the first few weeks of the
colony's existence this single individual performs a variety of tasks of
racial as well as of purely egoistic value; but as time goes on, a
profound change comes about in her activities and in the life of the whole
community. The members of the first brood do not grow into counterparts of
their mother; they are all sexless "workers" who progressively relieve
their parent of the tasks of nest-building and foraging and nursing, so
that their mother becomes a "queen" who devotes her entire time to the
special reproductive task which she only can perform. We may justly
compare the queen to the reproductive organ of _Hydra_, for the values to
the life of the species are identical in the two cases, while the various
classes of workers are counterparts of such units as the muscle and nerve
and nutritive components of the _Hydra_ or any other cell-community
individual. Another resemblance between the two is found in the death of
all the sexless individuals at the end of the season, when reproducing
males and females are finally formed, of whom the fertile queens only
survive in their winter hiding places; and again we can discover the cause
for biological death in that division of labor which calls upon certain
members of the whole community to perform tasks that have no value when
once provision has been made for perpetuating the species. Finally the
mode by which the colony grows and amplifies is in all respects like the
embryonic development of an egg into a _Hydra_, so that we may add the
phrase "social embryology" to our vocabulary. The original female is an
undifferentiated master of all trades; the small tribe she first
establishes is little better off than a horde of savages; but during its
seasonal existence the community increases in numbers and complexity until
it advances well toward the civilized condition, when each class performs
its special task for the good of all.