Pearson, Woods, and Thorndike, who have also shown that the strength of
inheritance in the case of mental traits is approximately the same as for
physical characteristics like stature and eye-color. Just as a worker-bee
inherits a specific form of nervous system which coöperates with the other
equally determined organic systems, wherefore the animal is forced to
perform "instinctively" its peculiar specialized tasks, so the mental
capacity of a human being is largely determined by congenital factors.
Upon these primarily depends his success or failure. It is quite true that
environment has a high degree of influence, so great indeed that some
speak of a "social heredity"; they mean by this phrase that the mental
equipment of an individual is determined by the things he finds about him,
or learns from others without having to invent or originate them himself.
Thus a Zulu boy acquires the habits of a warrior and a huntsman when he
grows up in his native village, although he would undoubtedly develop
quite different aptitudes if he should be taken as an infant to a city of
white men. Nevertheless his mental machinery itself would be no less
surely determined by heredity, even though the things with which it dealt
would be provided by an alien environment.
Our present knowledge of the nature and history of human mentality enables
us to learn many lessons that have a direct practical value, although it
is impossible under the present limitations to give them the full
discussion they deserve. Starting from the dictum that physical
inheritance provides the mechanism of intellect, education and training of
any kind prove to be effective as agents for developing hereditary
qualities or for suppressing undesirable tendencies. Just as wind-strewn
grains of wheat may fall upon rock and stony soil and loam, to grow well
or poorly or not at all according to their environmental situations, so
children with similar intellectual possibilities would have their growth
fostered or hampered or prevented by the educational systems to which they
were subjected. But the common-sense of science demonstrates that the
mental qualities themselves could not be altered _in nature_ by the
circumstances controlling their development any more than the hereditary
capability of the wheat grains to produce wheat would be altered by the
character of the ground upon which they fell. Education and training thus
find their sphere of usefulness is developing what it is worth while to
bring out, and inhibiting the growth of what is harmful. That heredity in
mental as well as in physical aspects provides the varying materials with
which education must deal is a fundamental biological fact which is too
often disregarded. It would be as futile for an instructor to attempt the
task of forcing the children in a single schoolroom into the same mental
mold, as it would be for a gymnasium master to expect that by a similar
course of exercise he could make all of his students conform to the same
identical stature, the same shape of the skull, or the same color of the
eye and hair.
* * * * *
Before leaving the subject of mental evolution we must return to the
conception of inseparable mind and matter with which the present
discussion began. The whole problem of human mental evolution is solved
when we accept the conclusion that the nervous mechanism and the total
series of its functional operations have evolved together in the
production of the human brain and human faculty. The case regarding the
physical organs rests solidly on the basis of the evidences outlined in a
previous chapter; the special examination of purely mental phenomena has
likewise been made in the foregoing sections. Just here we must pause to
give further attention to the invariable relation between the human mind
and the human brain.
The personality of human consciousness consists of the current of thoughts
and feelings flowing continuously as one of them rises for a time to
dominance only to fade when it leads to and is replaced by another
dominant element of thought. This current is affected by the messages
brought to the brain by nerves from the outer parts of the body where lie
the eye and ear and other sense-organs. In like manner the various
non-nervous parts of the body exert their influences upon consciousness,
but the affective processes, as they are called, are not as well understood
as the impressions passed inwards by the sense-organs along their nervous
roadways to the central organ, the brain. But the brain is the place where
the thinking individual resides; and this is one of the most important
teachings of psychology, for not only does it help us to understand the
evidence that human faculty has evolved, but it also inevitably brings us
to consider certain vital questions of metaphysics, such as the
immortality of the thinking individual after the material person with its
brain ceases to exist. However, the latter question is something which
does not concern us here; now it is most important to realize how
completely mind is connected with the brain.
Many of the facts demonstrating this connection are matters of common
knowledge. In deep and dreamless sleep the essential tissues of the brain
are inactive, and in correspondence with the cessation of material events
the thinking individual actually ceases to exist for a time. Any one who
has ever fainted is subsequently aware of the break in the current of
human consciousness when the blood does not fully supply the brain and
this organ ceases to function properly; a severe blow upon the head
likewise interrupts the normal physical processes, and at the same time
the mind is correspondingly affected. Again, a progressive alteration of
the brain as the result of diseased growth causes the mind to grow dim and
incapable. Sometimes infants are born which are so deficient mentally as
to be idiots, and an examination of the brain in such a case reveals
certain correlated defects in physical organization. These and similar
facts form the basis for the dictum that the development and evolution of
the brain mean the growth and evolution of human intellect.
The further question as to the nature of the connection is interesting,
but it relates to matters of far less consequence to the naturalist than
the central fact of the invariable relation which does exist. Throughout
the centuries many philosophers and naturalists of numerous peoples have
endeavored to explain the connection in question in ways that have been
largely determined by the changing states of knowledge of various periods,
as well as by differences in individual temperament. Three general
conceptions have been developed: first, that the material and mental
phenomena _interact_; second, that they are _parallel_; and third, that
they are _one_.
According to the first view, the individual thoughts and feelings forming
elements in the chain of consecutive consciousness are affected by the
events in the material physiology of the brain as a physical structure;
the latter in turn react upon the psychical or mental elements. Thus there
would be two complete series of phenomena, which are interdependent and
interacting at all times, although each would be in itself a complete
chain of elements.
The second interpretation is that the two series of events--namely, the
physical processes of the brain and the elements of consciousness--are
completely _independent_ but entirely parallel. As one writer has put the
case, it is as though we had two clocks whose machinery worked at the same
rate and whose relationships were such that "one clock would give the
proper number of strokes when the hands of the other pointed to the hour."
But in my opinion this attempted explanation of the relation of mind to
matter evades the whole question, as it does not account for the
dependence of the former upon the latter, but merely assumes the existence
of a more ultimate and unknown group of causes for a parallelism in the
rates of operation of two series of things regarded as disconnected.
The third conception recommends itself to many on account of its greater
simplicity. Formulated as the doctrine of monism, it states that the mind
and its material basis are merely different _aspects_ of one and the same
thing, and that there is only one series of connected elements which are
known to us directly as the current of our thoughts and indirectly as the
physiological processes going on mainly in the cerebrum. Thus mind is
purely subjective, the brain is only mediately objective. It is because
the mental and the material are so intimately related that the monist
believes them to be connected as are the lungs and respiration, the hand
and grasping, or the eye and the reception of visual impressions from
without.
But whichever one of these explanations we choose to adopt as our own, the
basic fact of primary importance is that there is an invariable dependence
of human thought upon a brain comprising a highly developed cerebrum,
whatever may be the ultimate nature of the way mental processes are
determined by physical processes, or _vice versa_. This fact stands
unquestioned and unassailable; human faculty and the brain cannot be
considered apart, even if they may not actually be different aspects of
the same basic "mind-stuff," as Clifford calls the ultimate dual thing.
Like all of the other organs of lesser importance belonging to the nervous
system, the brain is a complex of tissues which in the last analysis are
groups of cell-bodies with their fibrous prolongations. When these
cellular elements are in operation, mental processes go on; the unit of
the mental process therefore is the functioning of a brain-cell. But we
know that the substance of a brain-cell is the wonderful physical basis of
life called protoplasm, that demanded our attention at the outset. The
chemicals that go to make up protoplasm are everywhere carbon, hydrogen,
oxygen, and other substances that are exactly the same outside the body as
inside. It is the combination of these substances in a peculiar way which
makes protoplasm, and it is the combination of their individual properties
which in a real even though unknown manner gives the powers to protoplasm,
even to that of a living brain-cell. Does science teach us, then, that the
ultimate elements of human faculty are carbon-_ness_ and hydrogen-_ness_,
and oxygen-_ness_, which in themselves are not mind, but which when they
are combined, and when such chemical atoms exist in protoplasm, constitute
mental powers? Plain common-sense answers in the affirmative. We need not,
indeed, we must not, attribute mind as such to rock salt or to the water
of a stream, but we do know that salts and water and other dead substances
may enter into the composition of the material brain which is the physical
basis of mind.
In my opinion the individual argument renders the monistic conception of
mind and matter unassailable. The food that we may eat and the water we
may drink are dead, and as such they display absolutely no evidence of
nervous or mental processes. When they enter our bodies, they with other
foods replenish the various tissues, and among these the parts of the
brain. In a material sense they become actual living protoplasm, replacing
the worn-out substances destroyed during our previous thinking; and their
properties are combined to make brain and thought, to play for a time
their part in life, and to pass back into the world of dead, unthinking
things. Every one of us knows that hunger reduces our ability to think
clearly and fully, and every one knows also that mental vigor is renewed
when fresh supplies of nourishment reach the brain. What can be the source
of mentality, if it is not something brought in from the outer world along
with the chemical substances which taken singly are devoid of mind?
Scientific monism frankly replies that it is unable to find another
origin.
We are thus brought to recognize, not only the continuity taught by
organic evolution, but also the uniformity of the materials constituting
the entire sensible world, inasmuch as the ultimate unit of all nervous
phenomena is the reflex act of a protoplasmic mass, which itself is a
synthesis of properties inhering in the chemical elements making up living
matter. Among inorganic things the mind-stuff units are combined in
relatively simple ways, and the "stuff" does not give any outward
evidences of "mind" as such. Living things are almost infinitely complex
as regards their chemical organization, and even in the very lowest of
them we can discern a cell-reflex element which, combined with others like
it, forms the unit of the compounds we call instinct, intelligence, and
reason. Hence through an analysis of mental evolution we are enabled to
form the larger conception of a continuous universe whose ultimate
elements are the same everywhere.
VII
SOCIAL EVOLUTION AS A BIOLOGICAL PROCESS
We now reach a critical juncture in our study of the foundations of
evolutionary doctrine, for we must pass at this point to an inquiry into
the nature and origin of human social relations. In undertaking this task
we may seem to leave the field which is properly that of organic
evolution, and many perhaps will be unwilling to view such aspects of
human life as materials for purely biological analysis, arrangement, and
explanation. But even before the reasons for doing so may be made
apparent, every one must admit that the subject of mental evolution, which
comprises so large a bulk of details expressly social in their character
and value, virtually compels us to scrutinize the history of the economic
and other interrelationships maintained by the human constituents of
civilized, barbarous, and savage communities. Language has been treated as
an individual mental product, and so have the arts of life and of
pleasure; but all of these things find their greatest utility in their
social usage,--in their value as bonds which hold together the few or many
human beings composing groups of lower or higher grade. Without
discovering any other reasons we would be impelled to take up social
evolution, for this process is inextricably bound up with the origin and
development of all departments of human thought and action.
If now this new field is actually to be included within the scope of the
laws controlling the rest of nature's evolution, two general conclusions
must be established. Although no formal order need be followed, it must at
some time be shown that human social relations are biological relations,
to be best explained only through their comparison with the far simpler
modes of association found by the biologist among lower orders of beings;
and in the second place it must be demonstrated that identical biological
laws, uniform in their operation everywhere in the organic world, have
controlled the origin and establishment of even the most complex societies
of men. So far no reason has been discovered by science for believing that
evolution has been discontinuous, holding true only for the merely
physical characteristics of humanity as a whole; and furthermore, the
impersonal student of nature finds ample positive evidences showing that
the basic laws of associations of whatever grade are exactly the same. For
these laws we are to seek.
Heretofore the doctrine of organic evolution has been discussed with
reference to the single individual organism viewed as a natural object
whose history and vital relations require elucidation. Both in the general
arguments of the first few chapters and in the fifth and sixth chapters
dealing with the single case of the human species, the proof has been
given that all of the structural and physiological characters of any and
every organic type fall within the scope of the principles of evolution,
by which alone they can be reasonably interpreted. It has been unjust in a
sense to ignore completely the importance of the organic relations of a
social nature to which we are now to turn, because no individual can exist
without having its life directly influenced, not only by other kinds of
organisms, but even more intimately by other members of its own species.
In a single day's activity we who are citizens of a great metropolis are
forced into contact with almost countless other lives, glancing off from
one and another after influencing them to some degree, and gaining
ourselves some impetus and stimulus from our longer or shorter intercourse
with each of them. Our varied social relations are so many and obvious
that it is quite superfluous to specify them as essential things in human
life. For the very reason that they are so obvious and constitute so large
a part of our daily life, we are in danger of conceiving them to be
exclusively human; we unconsciously regard them as different from anything
to be found elsewhere and quite independent of the biological laws
controlling the human unit.
On the contrary, as we trace the development of social organization from
its earliest rudiments it becomes ever clearer that evolution has been
continuous, and that during later ages there has been no suspension of the
natural laws which earlier produced the human type of organism. The
lessons we have learned are by no means to be ignored from this point
forward; all of our conceptions of human biological history must be kept
in mind, for anything new that we may learn is superadded to the rest,--it
cannot disturb or alter the foundations already laid. It is even more
important to realize that the same scientific method is to be employed
which has been so fruitful heretofore. It has given us interesting facts;
it has indicated the most profitable lines of attack upon one and another
scientific problem; and it has demonstrated the practical value of
accurate knowledge, even of information about the evolutionary process. As
familiarity with the laws of human physiology enables one to lead a more
hygienic and efficient life, and as the results of analyzing the evolution
of mentality make it possible to advance intellectually with greater
sureness, conserving our mental energies for effort along lines
established by hereditary endowment, so now we are justified in expecting
that a clear insight into the origin of our social situation and social
obligations will have a higher usefulness beyond the value of the mere
interest inhering in our new knowledge. Every one is necessarily concerned
with social questions; never before has there been so much world-wide
discussion of topics in this field. And while it is true that much good
may be accomplished in utter ignorance of the past history of human
institutions and of the underlying principles which control the varied
types of organic associations, surely enlightened efforts will be more
effective for good. Therefore every member of a community who is capable
of thinking straight rests under an obligation imposed by nature to learn
how he is related to his fellow-men; he must act in concert with them or
else he forfeits his rights as a social unit. And it is his clear duty to
search among the results of science for aid in ascertaining what he ought
to do, and what reasons are given by evolution for the nature of his vital
duties.
Despite the growing appreciation of the fundamental relation between
biology and sociology, it is still far from universal. That the latter
science is in a sense a division of the former is more often recognized by
the biologist than by the average well-informed student of human social
phenomena. The layman in sociology too often concerns himself solely with
the complexities of the human problems, and he remains unaware of the
manifold products in the way of communal organisms far lower in the scale
of life firmly established as primitive biological associations ages
before the first human beings so advanced in mental stature that tribal
unions were found good. Among insects especially the biologist finds many
types of organized living things, ranging widely from the solitary
individual--a counterpart of something even more primitive than the most
unsocial savage now existing--up to communities that rival human
civilization, as regards the concerted effect of the diversified lives of
the component units. The student of the whole of living nature is favored
still more in that he learns how the make-up of such a simple organism as
a jellyfish displays principles underlying the structure of the whole and
the interplay of the parts that are identical with principles of
organization everywhere else. And all of these things can be dealt with in
a purely impersonal way which is impossible when attention is restricted
to the human case alone. Thus it becomes the biologist's privilege and his
duty as well to place his findings before those who wish to understand the
constitution of human society in order that evils may be lessened and
benefits may be extended. He does this so far as he may be able in full
confidence that the elements and basic principles are discoverable in
lower nature, just as they are in the case of the material make-up and
mental constitution of the single human individual.
A more explicit preliminary statement must now be given of the grounds for
the belief that social evolution is but a part of organic evolution in
general. Some of these reasons are not far to seek, but their cogency can
scarcely be appreciated until we have examined the concrete facts of the
whole biological series. Any human society selected for examination--be it
a tribe, a village community, or a nation--is in last analysis an
aggregate of human units and nothing besides. Its life consists of the
combined activities of such components--and nothing else. Could we
subtract the members one by one, there would be no intangible residuum
after all the people and their lives had been taken away. When these
simple facts are recognized, it is clear at once that the concerted
activities performed by biological units cannot be anything but organic in
their ultimate basis and nature; the evolution of such activities thus
takes its place as a part of organic evolution.
The task of tracing out the history of social organizations of whatever
grade can now be defined in precise terms: in simple words, it is to learn
how the activities of the component biological units making up any
association really differ from the vital performances of biological units
existing by themselves. What is it that distinguishes a savage of
antiquity from an American of to-day? The modern example is just as much
an animal as the earlier type, and his physiology is essentially the same.
It is something added to the common biological qualities of all men, some
relation which does not appear as such in the life of rude tribes, that
makes the distinction. And it is just this superadded relation that
requires explanation, as regards its exact biological value and its
historic development as well.
In undertaking this difficult task, it seems best to begin with the very
simplest organisms that biology knows, working upwards through the scale
to man. By this course the most basic elements of organization can be
discovered without having to look for them among the intricate details of
our own vital situation, where secondary and adventitious elements stand
out in undue prominence, and where the impersonal view is well-nigh
impossible. Step by step we will then work up the scale of social
morphology, approaching in the natural evolutionary order that part of the
subject which interests us most deeply.