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ESSAYS OF A BIOLOGIST
* * * * * *
DUCTLESS AND OTHER GLANDS
_Fred E. Wynne, M. B._
A brief description of the results of recent research into the
physiology and functions of the ductless glands and the application of
this knowledge to the prevention and cure of disease.
* * * * * *
ESSAYS of a BIOLOGIST
by
JULIAN HUXLEY
[Illustration: Logo]
New York
Alfred · A · Knopf
1923
Copyright, 1923, by Alfred A. Knopf, Inc.
Published October, 1923
Set up, electrotyped, printed and bound by the Vail-Ballou Press, Inc.,
Binghamton, N. Y.
Paper furnished by W. F. Etherington & Co., New York.
Manufactured in the United States of America
TO MY COLLEAGUES AND FRIENDS
AT THE RICE INSTITUTE
HOUSTON, TEXAS
PREFACE
A preface should be long, like one of Mr. Shaw’s, or short. I propose
the latter.
The essays here collected were written on very various occasions. This
must excuse the considerable overlap that will be found among them. I
have not thought it worth while to attempt to get rid of this, since,
though facts may be repeated, the point of view and general context are
on each occasion different.
Contrary to all custom, I have put the meat courses at the two ends
of my menu. If an author may presume to advise his readers, I would
suggest that, after finishing the first essay, they should (if they
retain a stomach for more) proceed at once to the last. This done, they
will find the others all in a sense lesser variations (if I may change
my metaphor) upon the same themes.
In spite, however, of the diversity of their occasions, there is a
common thread running through them, a common background of ideas. I
do not know whether I am justified in calling those ideas especially
biological, but they are certainly ideas which must present themselves
to any biologist who does not deliberately confine himself to the
technicalities of his science.
The biologist cannot fail to be impressed by the fact that his science
to-day is, roughly and broadly speaking, in the position which
Chemistry and Physics occupied a century ago. It is beginning to reach
down from observation to experimental analysis, and from experimental
analysis to grasp of principle. Furthermore, as the grasp of principles
in physico-chemical science led speedily to an immense new extension
both of knowledge and of control, so it is not to be doubted that
like effects will spring from like causes in biology. But whereas the
extension of control in physics and chemistry led to a multiplication
of the number of things which man could do and experience, the
extension of control in biology will _inter alia_ mean an alteration
of the modes of man’s experience itself. The one, that is to say,
remained in essence a quantitative change so far as concerns the real
life of man; the other can be a qualitative change. Applied physics and
chemistry bring more grist to the mill; applied biology will also be
capable of changing the mill itself.
The possibilities of physiological improvement, of the better
combination of existing psychical faculties, of the education of
old faculties to new heights, and of the discovery of new faculties
altogether--all this is no utopian silliness, but is bound to come
about if science continues her current progress.
Take but one example. In the first half of last century, hypnotism, or
mesmerism as it was then called, was in complete scientific disrepute.
To-day, all the main claims of its founders have been verified, and
many new facts unearthed. Every text-book on the subject will tell
you that men may be made insensible to pain by hypnosis alone without
any drug, many women even being delivered of children under its
influence without suffering. Temperature can be changed, blisters
raised, and many other processes not normally under the control of the
will can similarly be affected. The mind can be raised to an abnormal
sensitiveness, in which differences between objects that are completely
unrecognizable in ordinary waking existence, such as those between the
backs of two cards in a pack, may be easily distinguished.
If such possibilities are open to the empiricism of the hypnotist,
what may we not await from any truly scientific knowledge of mind,
comparable even in low degree to our knowledge of, say, electricity?
But these in a sense are all details, relevant in a way, and yet only
details. There is something still more fundamental in the biologist’s
attitude. He has to study evolution, and in that study there is brought
home to him, more vividly than to any one to whom the facts are not so
familiar, that in spite of all appearances to the contrary there has
been, throughout the whole of evolution, and most markedly in the rise
of man from his pre-human forbears, a real advance, a progress.
He sees further that the most remarkable single feature in that
progress has been the evolution of self-consciousness in the
development of man. That has made possible not only innumerable single
changes, but a change in the very method of change itself; for it
substituted the possibility of conscious control of evolution for the
previous mechanism of the blind chances of variation aided by the
equally blind sifting process of natural selection, a mechanism in
which consciousness had no part.
Most of mankind, now as in the past, close their eyes to this
possibility. They seek to put off their responsibility on to
the shoulders of various abstractions which they think can bear
their burden well enough if only they are spelt with a capital
letter:--Fate--God--Nature--Law--Eternal Justice--and such like. Men
are educated to be self-reliant and enterprising in the details of
life, but dependent, unreflective, _laissez-faire_ about life itself.
The idea that the basis of living could be really and radically altered
is outside most people’s orbit; and if it is forced upon their notice,
they as often as not find it in some way immoral.
Closely connected with this, in a sense its corollary, we have the fact
that ninety-nine people out of a hundred are concerned with getting a
living rather than with living, and that if for any reason they are
liberated from this necessity, they generally have not the remotest
idea how to employ their time with either pleasure or profit to
themselves or to others.
There are two ways of living: a man may be casual and simply exist,
or constructive and deliberately try to do something with his life.
The constructive idea implies constructiveness not only about one’s
own life, but about that of society, and the future possibilities of
humanity.
In pre-human evolution, the blind chances of variation and the blind
sifting of natural selection have directed the course of evolution
and of progress. It is on survival and the production of offspring
that the process has hinged; the machinery is in reality blind, but
these emerge as its apparent ends or purposes. The realization of ever
higher potentialities of living substance has happened, but only as a
secondary result and slow by-product of the main process.
In human evolution up till the present, the apparent ends and aims
have for the most part and in the bulk of men remained the same; it is
only the methods of pursuing them that have changed. True or conscious
purpose comes in and aids the unconscious biological forces already at
work.
However, to most men at some time, and to some men at most times,
these purely biological ends and purposes of life become altogether
inadequate. They perceive the door opened to a thousand possibilities
higher than this, all demanding to be satisfied. The realization of
what for want of a better term we can call spiritual values becomes
the true end of life, superposed on and dominating the previous
biological values.
When civilizations and societies are organized so that their prime
purpose is the pursuit of spiritual values, then life will have
passed another critical point in its evolution; as always, what has
gone before is necessary as foundation for what is coming, and the
biological conditions must be fulfilled before the new and higher
edifice can be built; but, as when the mammals superseded the reptiles,
so this change of aim will mean the rise of a new type to be the
dominant and highest form of life.
This can only come about so far as man consciously attempts to make
it come about. His evolution up to the present can be summed up in
one sentence--that through his coming to possess reason, life in his
person has become self-conscious, and evolution is handed over to him
as trustee and director. “Nature” will no longer do the work unaided.
Nature--if by that we mean blind and non-conscious forces--has,
marvellously, produced man and consciousness; they must carry on the
task to new results which she alone can never reach.
Mr. Trotter, in his delightful book on the Herd-instinct, draws
a distinction between the stable-minded or resistive and the
unstable-minded or adaptive, and points out how the destinies of
society have usually been entrusted to the former--whence spring our
persecutions of prophets and our neglect of innovating genius. This
will continue so long as the accepted belief of the majority is that
there exists a Providence who has assigned every one his proper place,
or even (oddest whim!) ordained the present type of society; so long
as they rely more on authority than experience, look to the past more
than to the future, to revelation instead of reason, to an arbitrary
Governor instead of to a discoverable order.
The general conceptions of the universe which a man or a civilization
entertains come in large part to determine his or its actions. There
are only two general and embracing conceptions of the sort (though any
number which are not general, and fail because they leave out whole
tracts of reality): in the fewest possible words, one is scientific,
the other unscientific; one tries to use to its fullest extent the
intellect with which we have been evolved, the other does not. The
thread running through most of these essays is the attempt to discover
and apply in certain fields as much as possible of this scientific
conception to several different fields of reality.
Of these essays, “Progress” has already appeared in the _Hibbert
Journal_, “Biology and Sociology” in the _Monist_, “Ils n’ont que de
l’âme” and “Philosophic Ants” in the _Cornbill Magazine_, “Rationalism
and the Idea of God” in the _Rationalist Press Annual_, and “Religion
and Science” in _Science and Civilization_, this year’s representative
of the annual “Unity” series edited by Mr. F. S. Marvin and published
by the Oxford University Press. They have all, however, been
considerably revised and enlarged before appearing in the present
volume. I have to thank the proprietors and publishers for kindly
permitting me to reprint these.
OXFORD,
_April 1923_.
CONTENTS
I PROGRESS, BIOLOGICAL AND OTHER 3
II BIOLOGY AND SOCIOLOGY 69
III ILS N’ONT QUE DE L’ÂME: AN ESSAY ON BIRD-MIND 107
IV SEX BIOLOGY AND SEX PSYCHOLOGY 133
V PHILOSOPHIC ANTS: A BIOLOGIC FANTASY 177
VI RATIONALISM AND THE IDEA OF GOD 207
VII RELIGION AND SCIENCE: OLD WINE IN NEW BOTTLES 235
I
PROGRESS, BIOLOGICAL AND OTHER
EVOLUTION: AT THE MIND’S CINEMA
I turn the handle and the story starts:
Reel after reel is all astronomy,
Till life, enkindled in a niche of sky,
Leaps on the stage to play a million parts.
Life leaves the slime and through all ocean darts;
She conquers earth, and raises wings to fly;
Then spirit blooms, and learns how not to die,--
Nesting beyond the grave in others’ hearts.
--I turn the handle: other men like me
Have made the film: and now I sit and look
In quiet, privileged like Divinity
To read the roaring world as in a book.
If this thy past, where shall thy future climb,
O Spirit, built of Elements and Time!
MUNICH, _Jan. 1923_.
PROGRESS, BIOLOGICAL AND OTHER
“Usus et impigrae simul experientia mentis
Paulatim docuit pedetemtim progredientes.”
--LUCRETIUS.
“As natural selection works solely by and for the good of each
being, all corporeal and mental environments will tend to progress
towards perfection.”
--CHARLES DARWIN.
“Social progress means the checking of the cosmic process at every
step and the substitution for it of another which may be called
the ethical process.”
--T. H. HUXLEY.
“It is probable that what hindered Kant from broaching his
theory of progress with as much confidence as Condorcet was his
perception that nothing could be decisively affirmed about the
course of civilization until the laws of its movement had been
discovered. He saw that this was a matter for future scientific
investigation.”
--J. B. BURY.
What is the most fundamental need of man? It would be interesting to
conduct a plebiscite of such a question, a plebiscite of the same sort
that was conducted by one of the French newspapers some years ago,
to discover the opinions of its readers as to who was the greatest
Frenchman of the century.
When I say the most fundamental need of man, I do not mean those basic
needs for food and drink and shelter which he shares with the animals:
I mean the most fundamental to him _as man_, as an organism differing
from all other organisms in the power of thought, in reflection and
self-consciousness. What variety of answers would be given, I dare not
guess; but I hazard the belief that the majority, if the suggestion
were put before them, would agree that his deepest need was to discover
something, some being or power, some force or tendency, which was
moulding the destinies of the world--something not himself, greater
than himself, with which he yet felt that he could harmonize his
nature, in which he could repose his doubts, through faith in which he
could achieve confidence and hope.
That need has been felt by all those to whom life has been more
than a problem of the unreflective satisfaction of instincts and
desires--however pure those instincts, or beautiful those desires;
it has been felt by all in whom the problem of existence has been
apprehended by intellect and disinterested imagination.
I say all. There may be rare creatures who, secure in strength of body
and mind and in unhampered unfolding of their faculties, possess a
confidence by which this need is never felt. They are like those whom
Wordsworth drew for us in the “Ode to Duty”:--
“There are who ask not if thine eye
Be on them; who, in love and truth,
Where no misgiving is, rely
Upon the genial sense of youth:
Glad hearts! without reproach or blot;
Who do thy work and know it not.”
But such are rare; or should we say that their type of mind, though
not uncommon in the earlier years of life, only by the rarest chance
achieves its course without a descent into that vale where the finite
human intellect grapples unequally with infinite problems?
The need has been felt in all ages and in all countries; and the
answers, the partial satisfactions of the needs which have been found
by the mind of men, are correspondingly diverse.
Savages have endowed the objects around them, living and inanimate,
with supernatural qualities. At a higher grade of development they
have created gods made with hands, visible images of their fears or
their desires, by whose worship and service they assuaged the urgent
need within their breast. Still later, turning from such crudity, they
became servants and worshippers of unseen gods, conceived under the
form of persons, but persons transcending human personality, beings in
whom was vested the control of man and of the world.
Up to this point there had been an increase of spirituality in the
constructions by which human thought satisfied its need; none the less,
the ideas underlying the mode of these constructions had not materially
altered. As Voltaire so pungently put it, man had created God in his
own image.
What remains? there remains to search in the external world, to find
there if possible a foundation of fact for the belief drawn from the
inner world of mind, to test the conceptions of a supreme being or
supereminent power against ever more and more touchstones of reality,
until the most sceptical shall acknowledge that the final construction
represents, with whatever degree of incompleteness, yet not a mere
fragment educed to fill a void, however inevitable, to satisfy a
longing, however natural, but the summary and essence of a body of
verifiable fact, having an existence independent of the wishes or
ideals of mankind.
It was the striving after some such certainty that led Matthew Arnold
to his famous definition of God as “something, not ourselves, which
makes for righteousness.” Dissatisfaction with the assertion that
belief in a very special and undemonstrable form of Divinity was
necessary as an act of faith has, in a large measure, helped the
widespread revulsion against orthodox Christianity. It was the need for
some external, ascertainable basis for belief which led such different
minds as William James and H. G. Wells to approach religion, and in
such diverse ways as in the “Varieties of Religious Experience” and in
“God the Invisible King.” It is this same need which is leading the
representatives of Christianity to lay ever greater stress upon the
reality and pragmatic value of the religious experience, less and less
upon dogmas and creeds.
It will be my attempt in this brief paper to show how the facts of
evolutionary biology provide us, in the shape of a verifiable doctrine
of progress, with one of the elements most essential to any such
externally-grounded conception of God, to any construction which shall
be able to serve as permanent satisfaction of that deepest need whereof
we have spoken.
Any such construction must take account of many separate parts of
reality. In the first place, it must consider those realities inherent
in the mind of man: his desire for goodness; the sense of value which
all agree is attached to certain experiences of mystics and to certain
religious emotions; his ideals and their importance for the conduct of
life. But in the second place it must consider those realities which
are independent of man and of his mind--the ascertainable body of hard
fact, those things which existed before ever he existed, which would
exist were he to disappear, with which he must struggle as best he may.
Lastly, there is the need for intermediation between the one and the
other reality, between the inner _felt_ and the outer _known_.
Mr. Wells,[1] if you remember, erected a new trinitarianism, which in
broad outlines corresponded with this division. With his particular
construction, I do not in many respects agree. But that some form
of trinitarianism is a reasonably natural method of symbolizing the
inevitable tripleness of inner experience, outer fact, and their
interrelation is obvious enough. In the particular trinitarianism
of Christianity, the reality apprehended to exist behind the forces
of Nature is called the Father, the upspringing force within the
mind of man, especially when it seems to transcend individuality and
to overflow into what we designate as the mystical, is called the
Holy Ghost, and the activity, personal or vicarious, which mediates
between the individual and the rest of the universe, reconciling
his incompleteness and his failures with its apparent sternness and
inexorableness, is called the Son.
Some men lay more weight on one of these aspects than on the others.
I know a clergyman of the Church of England who, on being reproached
during a theological argument with failure to pay sufficient respect
to the doctrine of God the Father, replied: “I am not interested in
God the Father”; and I know intellectually-minded men who wish to
reject the validity of all religious experience because their minds
are so made that they pay more attention to external fact and because
their reason refuses to let them agree with the interpretations of
fact propounded by most religious bodies. But, for a properly balanced
construction, for the finding of something which shall serve not as the
basis of a creed for this or that sect, but of a creed for humanity, of
something which instead of dividing shall unite, we need all aspects.
The idea of Progress constitutes, as I hope to show, the most important
element in the first part of our construction--that which attempts to
synthesize the facts of Nature; and besides, no inconsiderable portion
of the third, the interrelation of inner and outer.
Readers of Bury’s interesting book on the Idea of Progress[2] will
perhaps, with me, have been surprised at the modernity of that
conception. He shows how, in antiquity, the idea was never a dominant
one, and further that the adumbrations made of it all lacked some
element without which it cannot be styled progress in the sense in
which that word is used to-day.
Not indeed till the late Renaissance can we say that the idea of
Progress became in any real sense incorporated with the common thought
of Western civilization. From then to the present it has suffered
many vicissitudes. Starting in the XVIIth century as little more than
a consciousness of the superiority of the present over the past, in
the XVIIIth it changed to a dogma, its adherents claiming that there
existed a “Law of Progress” leading inevitably to the perfectioning
of humanity. In the XIXth century the dogma was questioned, and
thinkers began to put it to the test--the test of comparing theory with
historical fact. A new lease of life, however, was given to the idea of
a law of progress by the evolution theory; but finally, of late years,
there has been a marked reaction, leading not only to a denial of any
such inevitable law, but often to a questioning of the very existence
of Progress in any shape or form.
It is the business of the philosopher and of the biologist to see
whether this scepticism be justified, and to find out by a more
scientific approach how much of the doctrine of Progress is valid.
To the layman it would seem inevitable, once the validity of the
evolution theory was granted, to concede the fact of Progress in some
form or another. If we accept the doctrine of evolution, we are bound
to believe that man has arisen from mammals, terrestrial from aquatic
forms, vertebrates from invertebrates, multicellular from unicellular,
and in general the larger and the more complex from the smaller and
simpler. To the average man it will appear indisputable that a man is
_higher_ than a worm or a polyp, an insect _higher_ than a protozoan,
even if he cannot exactly define in what resides this highness or
lowness of organic types.
It is, curiously enough, among the professional biologists that
objectors to the notion of biological progress and to its corollary,
the distinction of higher and lower forms of life, have chiefly been
found. I say curiously enough, and yet to a dispassionate observer it
is perhaps not so curious, but only one further instance of that common
human failing, the inability to see woods because of the trees that
compose them.
That is as it may be. Our best course will be to start by examining
some of the chief objections to the idea of biological progress, in
order to see if they involve errors of thought which we may then avoid.
The most widespread of all the objections raised may, I think, be
fairly put as follows: “The fundamental attribute of living beings
is adaptation to environment. A man is not better adapted to his
environment than the flea which lives upon him as a parasite, or than
the bacillus which kills him, nor is a bird better adapted to air than
a jelly-fish to water; therefore we have no right to speak of one as
higher than the other, or to regard the transition from one type to
another as involving progress.”
A second class of objector is prepared to admit that there has been
an increase of complexity, an increase in the degree of organization
during evolution, but refuses to allow that increase of complexity
has any value in itself, whether biological or philosophical, and
accordingly refuses to dignify this trend towards greater complexity by
the name of progress.
Yet a third difficulty is raised by those who ask us to fix our
attention on forms of life like Lingula, the lamp-shell, which, though
millions of years elapse, do not evolve. If there exists a Law of
Progress, they say, how is it that such creatures are exempt from its
operations?
Finally, a somewhat similar attitude is adopted by those who refuse
to grant that evolution can involve progress when it has, as we know,
brought about well-nigh innumerable degenerations. Granted, for
instance, they would say, that the average Crustacean is in many ways
an improvement upon the simple form of life from which we must suppose
that it arose, yet we know that within the group of Crustacea there are
several lines of descent which have led to the production of parasitic
forms--animals in which the activity and complex organization of the
ancestral type has been sacrificed, and as end-product we are presented
with a hateful being, an almost shapeless mass consisting of little
else but over-developed reproductive organs and mechanisms for sucking
nutriment from its unfortunate host. Such a result is revealed to us
in the Crustacean form Sacculina, and is paralleled by countless other
examples in almost every class of animals. The degradation of parasites
and sedentary types is equally a product of the evolutionary process
with the genesis of the ant, the bird or the human being; how then can
we call the evolutionary process progressive?
These are important objections. Can they be met? In the broadest way
they can and must be met by the only possible method, the method of
Science, which consists in examining facts objectively, and by drawing
conclusions not a priori, but a posteriori. A law of Nature is not (and
I wonder how often this fallacy has been exploded, only to reappear
next day)--a law of Nature is not something revealed, not something
absolute, not something imposed on phenomena from without or from
above; it is no more and no less than a summing-up, in generalized
form, of our own observations of phenomena; it is an epitome of fact
from which we can draw several conclusions. By beginning in this way
from the very beginning, by examining the basis of our mode of thinking
in natural science, only thus are we enabled to see at one and the same
moment how to investigate the question of progress on the constructive
side, and how to neutralize the force of the objections to the idea.
Questions of fact are simple to deal with. It is indubitable that some
forms of life remain stationary and unevolving for secular periods; it
is equally indubitable that degeneration is widespread in evolution.
These are facts. But we are not therefore called upon to deny the
possibility of progress. To do so would be to fall into the error
of reasoning which we have already condemned. It remains for us to
take these facts into account when examining the totality of facts
concerning organic life, and to see whether, in spite of them, we
cannot discover a series of other facts, a movement in phenomena, which
may still legitimately be called progress. To deny progress because of
degeneration is really no more legitimate than to assert that, because
each wave runs back after it has broken, therefore the tide can never
rise.
Similarly with the first two objections. If the degree of adaptation
has not increased during evolution, then it is clear that progress
does not consist in increase in adaptation. But it does not follow
that progress does not exist; it may quite well consist in an increase
of other qualities. So with complexity. Complexity has increased, but
increase in complexity is not progress, say the objectors. Granted:
but may there not be something else which has increased besides mere
complexity?
No; the remedy for all our difficulties, and indeed the only way in
which we can arrive at the _possibility_ of saying whether biological
progress exists or no, is to adopt the positive method.
Let us then begin our survey of biological evolution in the endeavour
to find whether or no progress is visible there. To start with, we must
be clear what are the sources of our knowledge on the subject.
Direct observation of progressive evolution has, of course, not yet
been possible in the period--biologically negligible--in which man has
directed his attention to the problem; and historical record is also
absent. The best available evidence is that of paleontology: here the
relative positions of the layers of the earth’s crust enable us to
deduce their temporal sequence--and naturally, that of the organisms
whose fossil remains they embalm--with a great deal of accuracy.[3]
We can scarcely ever observe the direct transition from the forms of
life in an older to those in a younger stratum, nor can we absolutely
prove their genetic relationship. But in a vast number of cases it is
abundantly clear that the later type of organization is descended from
the former--that a group of forms in the younger stratum had its origin
in one or more species of the group to which the forms in the older
stratum belong. Sometimes, however, as in many groups of mammals, the
gaps are few and small, the seriation almost complete. In any event we
have here evidence which, so far as it goes, is perfectly admissible
for the main lines and for many of the smaller branches of evolutionary
descent.
Unfortunately, it does not go very far--or, we had better say, it is
of restricted application. By the time we find well-preserved fossils
in the rocks, the main groups of the animal kingdom and their chief
subdivisions had been already differentiated, with the one important
exception of the vertebrates; while time, heat, and pressure have
so modified the earlier strata as to destroy the fossil forefathers
of insects, molluscs, crustacea, and the rest, which they must have
contained.
Within the vertebrate stock, then, we can learn a great deal from
the semi-direct methods of paleontology: but for the history of the
other groups and for their origin and interrelations, we are driven
back upon comparative anatomy and embryology, into another field of
more circumstantial evidence. When, for instance, we find that the
fore-limbs of bat, bird, whale, horse, and man, although so different
in function and in detail of structure, are yet built upon the same
general plan, and upon a plan wholly different from that of the
limbs, say, of a spider or an insect, we must either deny reason and
say that this similarity means nothing; or assume that its cause
is supernatural, outside the province of science, that it is the
expression of some eternal Idea, or some plan of a personal creator
(in which case, be it noted, the idea or the plan often appears to
our intellect as unreasonable and indeed stupid); or finally that it
implies community of origin with later divergence of development. When
we are dealing with the smaller sub-divisions of some larger group,
this method too gives us information of the same order of accuracy as
does paleontology: but when we try to understand the relationships
of these larger groups, then we are forced to renounce any claim to
detailed knowledge. In broad outline, however, a great deal still
remains, and this broad outline we can employ for our valuation of the
whole sweep of biological progress, just as we can use the greater
accuracy of vertebrate paleontology and comparative morphology to fill
in the detail within a restricted field of its operation. From these
various evidences, direct and indirect, we can paint for ourselves a
picture of the evolution of life which, in spite of inevitable gaps and
errors, is in its main features adequate and true.
Let us not be misled by the fact that disputes can and justifiably do
arise over details: as Professor Bateson put it recently[4]:--
“If the broad lines do not hold, then we must sink into irrationality
or turn to flagrant supernaturalism.”
Let us then remind ourselves of some of these broad lines.
We know that there was a time when the earth, hot and fiery, could
not have been the abode of life. Of the first origins of life we know
nothing and guess little. What we can justifiably surmise is that
the protoplasm of the original organisms was not yet differentiated
into cytoplasm and nucleus, and that sexuality had not yet arisen.
The bacteria, however specialized in other ways, are still in this
primitive condition.
Later, we can with great probability infer that the independent
units into which the stuff of life was subdivided reached a size
which, though still minute, was at least not beyond or even close to
the limits of microscopic vision; they were further provided with a
nucleus, and occasionally underwent sexual fusion. In other words, they
showed an organization which we call cellular; they were free-living
cells. Such unicellular creatures must have been at one epoch sole
inhabitants of the earth, and diverged into the most manifold types of
structure and modes of life. Such of them as led an animal as opposed
to a plant type of existence would be classified under the Protozoa or
unicellular animals.[5]
The colonial habit gives advantages of increased size and greater
rapidity of motion, of which many Protozoa have availed themselves. A
colonial existence once attained, division of labour, at first between
the germinal and the somatic, later between different types of somatic
units, will be a further advantage. Such organisms, of which we cannot
say definitely whether they are compound aggregates or single wholes,
would represent the most natural link between the unicellular Protozoan
and the rest of the animal kingdom, the multicellular forms or Metazoa.
And indeed such organisms exist at the present day--organisms such as
Volvox, Zoothamnium, Proterospongia, and Myxidium--as adjuvant and
confirmatory of our reasonable faith.
The multicellular organisms appear to have originated twice over, by
divergent routes. There are the true Metazoa, to which belong all the
higher types, and the Parazoa or sponges, which have never passed
beyond a very primitive type of structure. Both start as simple sacs,
whose walls are formed from two primary sheets or layers of cells.
Leaving sponges out of account, the Hydroid polyps are the simplest
representative of this grade of structure, while some of the Jelly-fish
and Siphonophores have attained the utmost limit of its inherent
possibilities.
The next great step was the intercalation of a third primary layer
between the other two. The result of this, the so-called triploblastic
type of organization, gives the ground-plan for all subsequent
organizations; and later evolution consists mainly in the evolution of
this ground-plan.
In other words, we can now pass from the consideration of the general
plan of life’s architecture to that of its details. During the next
great tract of time, that which was novel in life (for we must not
be guilty of a _petitio principii_ in yet speaking of “advance” or
“progress”) was brought about in two main ways--by an increase in
the size of organisms, and by an increase in the efficiency of their
working.
The simplest Metazoa, such as the polyps, as well as the simplest
three-layered forms, such as the free-living flat-worms, are all small,
composed of an amount of material comparable with that contained in a
single one of our hairs. In every group of Metazoa, increase of size is
one of the main features that accompanies specialization, and the more
specialized groups possess a higher average size than the less.
A jelly-fish against a polyp; a cuttle-fish against a primitive
mollusc; a vertebrate against its chordate ancestor; the giant reptiles
of the late secondary period against their forbears; a horse against
Phenacodus; man against the earliest primates--over and over again does
size increase with the march of time.
Not only this, but when there occurs aggregation of individuals to
form units of a higher order, as in bees and ants and termites, and in
man himself, there too increase of size in the new units thus produced
is one of the most notable features. Is not human history in large
measure the history of the increase in size of social units?
But size alone is not enough; there is also a definite improvement of
the details of life’s mechanism--partly revealed as improvement in the
efficiency of the parts themselves, partly in the adjustment of the
parts to each other, and their subordination to the needs of the whole.
It is scarcely necessary to detail the improvements in efficiency of
different organs during evolution: such are universally familiar. But
a few examples will point my moral. The lowest three-layered forms
have no circulatory system; this, rendered necessary later by increase
of size, shows a gradual differentiation of parts in evolution. The
exquisite machinery of our heart is directly descended from a minute
pulsating ventral vessel such as that seen in Amphioxus. Protection and
support are better cared for in insect than in worm, in mammal than in
lamprey. But the most spectacular improvement of function, the most
important of all the directional movements in evolution has been that
affecting the nervous system and the sense-organs associated with it.
Few people who have not gone carefully into the subject realize how
imprisoned and windowless are the existences led by lower forms of life.
Even such physically well-organized creatures as Crustacea stand at
an amazingly low mental level. The other day I was reading a careful
account of experiments on the behaviour of crabs. The method by which
the sexes recognize each other is so crude that I am not sure whether
it deserves the term recognition at all. Before mating, which takes
place immediately after a moult, the female is carried about for some
time in the claws of the male. The mature males will attempt to lift
up and carry off any members of the same species, male or female: but
the only ones which will permit themselves to be thus carried about are
females just before moulting. Hence by a general instinct to lift any
members of the same species on the part of the males, and on the part
of the females an instinct to allow themselves to be lifted when in
the physiological condition which precedes moulting, the required end
is brought about. But of any mental operation such as is involved in
sex-recognition in man or any other mammal, there is no evidence.
Fish, to take another example, possess associative memory; they can
learn. But they learn very slowly, and learn only the simplest things.
The jump from their powers of memory to those of a dog, who can be
trained comparatively quickly to carry out complicated tricks, is as
great as the further jump from the powers of a dog to those of a man
capable of learning a page of print by heart in two or three readings.
The first organs connected with mind to become elaborated are the
organs of sense: but such _receptor_ organs are useless to their
possessor, however elaborate, unless put into relation with proper
_effector_ organs--organs for action, whether locomotor or secretory.
So that the first steps are the elaboration of sense-organs, the
increase of efficiency of muscles and glands, and, equally essential,
the construction of an improved “_adjustor system_,” whereby the
stimulus falling on the sense-organ may be translated into action and
into the right kind of action. This adjustor mechanism is the central
nervous system. Most of the further history of organisms may be summed
up in one phrase--the evolution of adjustor mechanisms.
At first, it is chiefly of importance to be brought into relation with
more and more of the happenings of the outer world, to be able to see
and hear and feel and smell more and more delicately; and to react upon
the outer world more and more efficiently and powerfully, to be able
to move and to handle matter more quickly and with finer and finer
adjustment.
But unless the adjustor mechanism be improved, this process soon tends
to a limit. I may illustrate my meaning by a simple supposition.
Suppose an organism capable of very little beyond reflexes and
instincts and with but a scanty dose of associative power: of what
conceivable use to it would be a telescope or a telephone? Man obtains
a biological advantage from such accessory sense-organs in that, when
thus apprised of events at a distance, he is enabled to plan out
courses of action to meet the events which he imagines are going to
overtake him: but both planning and imagination are entirely functions
of an adjustor mechanism, and without such a mechanism, great
enlargement of sensory power would only result in an organism reacting
too often and unnecessarily to events in its environment.
There is, in fact, an obvious limit to the perfection which can be
attained by receptor and effector organs. Striated muscles, the
modelling of the skeleton and joints for speed in a horse or greyhound,
the eye and ear of higher vertebrates, the mammalian sense of smell--no
doubt it would be possible for life to have produced more perfect and
more efficient mechanisms--but not, apparently, mechanisms _much_
more perfect or _much_ more efficient. They stand near the limit of
biological efficiency.
There thus comes a time when it is impossible or extremely difficult
to give an organism advantage in the struggle by improving its
sense-organs or its locomotor system, or indeed any of its general
physical construction, whereas it is still possible to confer the most
important advantages upon it by means of improvements in the adjustor
mechanism, improvements which involve and imply improvements of mind.
This stage was reached by mammals and birds quite early in the Tertiary
period; and one of the most striking spectacles of biology, revealed
in the fossils of successive strata, is to see Mind coming into its
own after this epoch. Over and over again a group of animals is seen
to appear and spread, only to be extinguished and replaced by another
type which to all outward appearance is similar, no better adapted
to the conditions of life. But the two types differ in one point: the
later possessed a larger brain, and so, from all analogy, a better
mind. Or, to take another example, man differs from the lower animals
in no notable _physical_ specialization except the upright posture.
After this critical point in the evolution of organisms was reached,
further development has consisted chiefly in the development of mind:
and this has meant, from the objective, purely biological standpoint,
the possibility of summing-up ever more and more power and fine
adjustment of response in the present, in the single act.[6]
The first main function of the improved adjustor mechanism was to make
ever more complicated actions possible; but this again tended speedily
to a limit. The next step was to make it possible for the past to
act in the present. Through associative memory, present behaviour is
modified by past experience. What this has meant to organisms can be
realized if we reflect that certain terms which can justly be applied
to a mammal or a bird have no real meaning if applied to lower forms.
If we speak of a cunning wolf or a wary crow, we imply that their life
has taught them new qualities; but it is nonsense to talk of a cunning
crab, and, though we might properly ascribe wariness to a trout, I
would not like to speak of a wary Amoeba. In the same way we can
justifiably say that one dog is affectionate, another intelligent:
but to speak of an affectionate earthworm or an intelligent snail has
no more proper significance than it would be to say that a dog was
intellectual or religious.
Quickness of learning then became of importance; but so long as the
faculty of generalizing is absent, associative memory, although
liberating organisms from the prison of a fixed and inherited
mental constitution, still pins them down to the accidental and the
particular; an organism can only learn to react to those particular
experiences which chance has decreed that it should have had.
The next and last salient step in evolution was a double one. Which
of its two parts came first is hard to say; probably they acted
reciprocally throughout. This step was, on the one hand, the attainment
of the power of generalization--of reason, concept-formation, or what
you will--and on the other the origin of tradition, which in its turn
was made possible by the acquisition of speech and of a gregarious mode
of life. By these means, the human species and its evolving ancestors
were gradually enabled, first, to free experience ever more and more
from the accidental and to store what was essential; and, secondly, to
bring gradually more and more of the experience of the whole race to
bear upon the present problem, and to plan further and further ahead,
and on a larger and larger scale.
This has meant, among other things, that for the first time in
biological history there has been an aggregation (in the technical
biological sense) of minds. Over and over again in evolution does
the process of aggregation appear.[7] It is an advantage, for at one
jump it lands life on a new level of size, with new possibilities of
division of labour and specialization. It appears in the aggregation
of Protozoa to form the colonial ancestor of all higher, many-celled
forms. It appears again on this new level in the aggregation of hydroid
polyps, of polyzoa, of ascidians, and especially in the beautiful
floating Siphonophora, in which the polyp-like units (themselves
historically aggregates of cells) have become so subordinate in
relation to the whole that they can often scarcely be recognized as
individuals, and the individuality of the aggregate is much more marked
than that of its components. It appears in a new way in the Termites
and in the social Hymenoptera--ants, bees, and wasps. Here the bonds
uniting the members of the aggregate are not physical but mental,
their sense-impressions and instincts; but the principle is identical
throughout. Finally in man we have not merely aggregation of physical
individuals held together by mental bonds, but aggregation of minds as
well as of physical individuals.
In many mammals and birds, each generation can extend its influence
on to the next, and the experience of the parents is in part made
available to the offspring. But never until the origin of speech was
it possible for a whole series of generations to be linked together
by experience, never could experience be cumulative, never could one
mind know what another mind, remote in time, had been thinking or
feeling. Biologically, evolution since the time of origin of this new
process has consisted essentially in the enlargement and specialization
of aggregations of minds, and the improvement of the tradition which
constitutes the mode of inheritance for these aggregations--that
tradition which, like Hugo’s “Nef magique et suprême” of human destiny,
will eventually have “fait entrer dans l’homme tant d’azur qu’elle a
supprimé les patries.”
It will, I hope, have been clear, even from the few examples which
I have given, that there has been a main direction in evolution. At
the close of the paper I shall try to point out that since motion in
this direction has led to the production of an increasing intensity
of qualities which we are unanimous in calling valuable, since in
other words the application of our scale of values tends in the same
direction as has the march of evolutionary history, that therefore
we are justified in calling this direction progressive, and indeed
logically compelled to give to motion in this direction a name which,
like progress, implies the idea of value.