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Vernon L. (Vernon Lyman) Kellogg.

Darwinism to-day; a discussion of present-day scientific criticism of the Darwinian selection theories, together with a brief account of the principal other proposed auxilary and alternative theories of species-forming online

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Online LibraryVernon L. (Vernon Lyman) KelloggDarwinism to-day; a discussion of present-day scientific criticism of the Darwinian selection theories, together with a brief account of the principal other proposed auxilary and alternative theories of species-forming → online text (page 36 of 38)
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us join the believers in the "unknown factors in evolution/"



378 DARWINISM TO-DAY.

Let us begin our motto with Ignoramus, but never follow
it with Ignoribimus.

Now if we do not know, but want to know, and are willing
to make an attempt toward knowing, where shall our energy
of exploration and discovery be first directed ? *
of evolution To what particular points or aspects of the
8tudy ' causes-of-evolution problem shall we give our

first attention, what fields of study first invade? What, in a
word, is the principal desideratum in present-day investiga-
tion of evolution? I should answer, the intensive study of
variability. Not alone of the statics of variation but of its
dynamics. Indeed, above all its dynamics. The experimental
study of the stimuli, external and internal, the influences,
extrinsic and intrinsic, which are the factors and causes of
variation, this is the great desideratum ; this the crying call
to the evolution student. Experiment in variation study
includes controlled modification of ontogeny (experimental
development) and controlled modification of phylogeny
(pedigreed breeding). In the study of variation statics,
biometry is the greatest advance in modern methods, and
the essential basis of biometric study, namely, quantitative
and statistical data, must have its part in the investigation
of variation dynamics. But in entering the realm of the
causal study of variability, "we must not," as Roux has
clearly pointed out, "conceal from ourselves the fact that
the causal investigation of organism is one of the most
difficult, if not the most difficult, problem which the human
intellect has attempted to solve, and that this investigation,
like every causal science, can never reach completeness,
since every new cause ascertained only gives rise to fresh
questions concerning the cause of this cause."

I believe that the neglect on the part of the selectionists to
pay sufficient attention to the origin and causes of the varia-
tion which is such an indispensable basis of their theory, has
been one of the most obvious reasons for the present strong



DARWINISM'S PRESENT STANDING. 379

reaction against the selection theories. Thankfully accept-
ing the bricks and stones handed to them they have builded
Neglect of a house of great beauty : but with stones of
causefofvLia! different sha P e * h use of quite different ap-
tion. pearance might have been built. Is it not a

cause for wonder that the selection masons have not been
more inquisitive concerning the whence and why of this
magical supply of just the needed sort of material at just the
right time? As a matter of fact, Darwin himself gave
serious attention to the origin of his always-ready varia-
tions, but his tremendous undertaking was too nearly super-
human already to permit him to add to it an adequate
attention to the problem of causes. But that same excuse
does not attach to his followers. And it is, I repeat, largely
this neglect to strive to penetrate the so-far unrent veil of
obscurity lying over the beginnings of species change that
has contributed to the growing revolt against the Allmacht
of the selection dogma. Who would in these days have a
following for his explanation of species origin must include
in his theory some fairly satisfying explanation of the first
visible beginnings of modification.

Then, after the explanation of the why and how of varia-
bility, comes the necessity of explaining the cumulation of
this variability along certain lines, the first visi-

ti<mTOmJated"7 ble issuance of these lines bein g as species, and
later becoming more and more pronounced as
courses of descent. This explanation has got to begin lower
down in phyletic history than natural selection can begin.
Before ever there can be utility and advantage there must
have come about a certain degree of heaping up, of cumu-
lating, of intensifying variations. What are these factors?
They are possibly only two : ( i ) orthogenetic or deter-
minate variation as the outcome of plasm preformation or
of epigenetic influences, and (2) the segregation of similar
variations by physiologic or topographic conditions. Hence,



380 DARWINISM TO-DAY.

next to the cause or origin of variability the great desider-
atum is a knowledge of the means of cumulating and direct-
ing variability. And both these great fundamental needs
of a satisfactory understanding of organic evolution seem
to me to be wholly unreferred to in the theory of natural
selection. To be sure the control and cumulation of such
large differences among organisms and species as are posi-
tively sufficient to determine the saving or the loss of life
are explicable by selection. And this factor is sooner or later
in any phyletic history bound to step in and probably
be the dominant one. But a species, or a character, will
always have a longer or shorter preselective existence and
history, and it is precisely these days before the Inqui-
sition of which we demand information. For of one thing
we are now certain, and that is, that evolution and the origin
of species have both their beginnings and a certain period
of history before the day of the coming of the Grand
Inquisitor, selection.

Finally there is still another desideratum and one whose
seeking will carry us into dangerous country. For while
there may be and are selectionists who might allow us to
fumble about in the darkness of preselective time for first
causes, there is probably none who will allow us to ques-
tion his right to explain that other element in evolution be-
sides species transformation, namely, adaptation, or, as the
Germans untranslatably put it, Zweckmdssigkeit. But by
no means all biologists * find in natural selection a sufficient
explanation of adaptation.

In the visible expression of organic evolution are two

chief elements, one the variety of life kinds, the existence of

The great species, the reality of lines of descent ; and the

need of explain- other the adaptedness and adaptiveness of these

adaptation. jj fe k j nds The var i eties Q f organ i c kinds show

themselves adapted in structure and function to the varie-
ties of environment and life-conditions. Hence, the task



DARWINISM'S PRESENT STANDING. 381

of an evolution explanation is a double one ; it must explain
not only diversity or variety in life, but adaptive diversity
or variety. And there is no gainsaying to the selection
explanation its claim to stand among all proposed explana-
tions of adaptation as that one least shaken by the critical
attack of its adversaries. However mightily the scientific
imagination must exert itself to deliver certain difficult
cases into the hands of selection, and however sophisticated
and lawyer-like the argument from the selection side may
be for any single refractory example, the fact remains that
the selectionist seems to be able to stretch his explanation
to fit all adaptations with less danger of finding it brought
up against positive adverse facts than is possible to the
champion of any other so far proposed explanation. The
explanation of adaptation by natural selection steers wide
of teleology on one hand and of unproved assumptions con-
cerning heredity on the other. The protoplasmic conscious-
ness of Cope and the automatic perfecting principle of
Nageli and those of his manner of explanation, are only
indirect ways of attributing to natural forces visions and
anticipations of what does not yet exist ; while the influence
of the ambient medium of St. Hilaire and of the extrinsic
factors of Eimer, and the impressing photographically on
the species and the carrying over into phylogeny, with
approximate identity, of characteristics and modifications
acquired ontogenetically by the individual as a result of
functional stimulation all these are assumptions not only
apparently unproved, but in the light of our present
knowledge of the mechanism of heredity seemingly un-
provable.

Yet the explanation of species transformation and of
adaptation by the introduction into phylogeny of modifica-
tions (reaction effects) arising in the individual during its
ontogeny, has to its credit a certain logical proof, or
basis, which has great validity in my mind, and yet which



382 DARWINISM TO-DAY.

has enjoyed little general recognition and almost no em-
phasis from supporters of Lamarckism or neo-Lamarckism.
As the great strength of the natural selection explanation of
species-change and adaptation lies precisely in the logical
nature of its premises and conclusions rather than on scien-
tific observation and experiment, 7 it certainly is not unfair
to emphasise any similar kind of proof tending to support
the Lamarckian type of explanation.

The logical proof that I refer to is simply this : It is a
universally admitted fact that environment and functional
A logical proof stimulation can and do modify organisms dur-
tL th ^hy d log- in g their lifetime, and that this modification
eny of adaptive i s usually plainly adaptive. It is also an
oSgTs!* 10 admitted fact that species differences or modi-
fications are often identical with these ontogenetic modifica-
tions. That is, that under similar environment or life
conditions species modification often follows the same lines
as ontogenetic or individual modification. Now when we
recall the possibilities of the hosts of ways in which the
necessities of adaptation to varying environment might be
met by selection among nearly infinite fortuitous variations,
and yet see that exactly that means or line or kind of adapt-
ive change occurs, which in the case of the individual is
plainly and confessedly a direct personal adaptive reaction
to varying environment, is it not the logical conclusion that
the species change and adaptation is derived, not by the
chance appearance of the needed variation, but by the com-
pelled or determined appearance of this variation ? In other
words when species differences and adaptations are identical
with differences and modifications readily directly produci-
ble in the individual by varying environment, are we not
justified, .on the basis of logical deduction, to assume the
transmutation of ontogenetic acquirements into phyletic
acquirements, even though we are as yet ignorant of the
physico-chemical or vital mechanism capable of effecting the



DARWINISM'S PRESENT STANDING. 383

carrying over? Has natural selection's claimed capacity to
effect species change, unseen by observer, untested by exper-
imenter, any better or even other proof of actuality than
that just offered on behalf of species modification as a direct
result of the stimulus of varying environment and func-
tional exercise? I cannot see that it has.

And this kind of argument, based half on observed facts

and half on deduction, may be extended even farther on

, behalf of the theory that species change is the

The same kind :

of proof for non- direct reaction to environmental conditions,
adaptive change. p or ^ere are many ontogenetic variations pro-
duced directly in response to environment that are not
plainly adaptive; many, indeed, between which and the
environmental conditions that produce them no reasonable
relation is apparent; no relation, that is, that would be ex-
actly expected or could be foretold until empirically deter-
mined. In other words, many apparently non-significant
ontogenetic differences or variations appear as direct result
of environmental influence or stimulus. For example, indi-
viduals of certain species of the Crustacean phyllopod genus
Artemia show marked structural differences when grown
in salt water of varying density. These differences are in
the size and shape of the plate-like lateral gills, the seg-
mentation of the post-abdomen, the length of the caudal
flaps (telson) and the hairiness of these flaps. The size of
the whole body is also affected, individuals developing in
water of higher density being markedly smaller than those
which have been grown in less dense water. Now of all
these differences only two seem to have what I call a rea-
sonable relation to the environmental differences. The in-
creased proportional size of the gills shown by the Artemias
grown in denser water appears to be a regulatory change
connected with the smaller amount of oxygen in the water,
and the decreased size of the body may similarly be con-
ceived by some to be an expected concomitant of the



384 DARWINISM TO-DAY.

denser water condition. But what of the extra abdominal
segment, the longer telson projections and their increased
hairiness, all of which as shown by Schmankewitsch " (how-
ever mistakenly this investigator may have interpreted his
results as examples of actual species modification) and
Anikin * for Artemia salina and by the writer 10 for Artemia
franciscanus, are the ontogenetic differences that varying
density of salt water actually produces in individuals of a
single Artemia species. These differences, these variations,
are of the sort that I am calling non-significant, non-adapt-
ive, non-reasonable. They would not be prophesied ; they
seem to have no reasonable correlation with the causes
which produce them. But they are actually the results or
effects of determined proximate causes which are extrinsic
or environmental. If now the logical argument (based on
identity of adaptive modification in individuals and in spe-
cies) for the transmutation of ontogenetic changes into
phyletic changes has any validity, then these non-adaptive,
indifferent modifications may be transmuted as well as the
adaptive ones, and thus hosts of trivial, non-adaptive indif-
ferent species differences be explained on this Lamarcko-
Eimerian basis as well as the obviously adaptive modifica-
tions. But I am not insisting on this sort of argument too
strongly. It is exactly the sort of argument upon which the
theory of natural selection chiefly rests, and I have cer-
tainly tried to make evident in this book my belief in the
danger of the substitution of this sort of logical or meta-
physical basis of belief in a theory for a scientific basis of
observation and experiment.

Finally, let us ask ourselves why we have adopted the

common belief that our search for a cause of variability is a

A suggestion search for some so far unknown, some quite

careTfvfria! new factor or force in biology ? May it not be
tion. that the factor is already familiar to us; so

familiar indeed perhaps that we are esteeming it too simple



DARWINISM'S PRESENT STANDING. 385

and too obvious to play the role of the Great Desideratum,
a causal factor of variability.

When one attempts to picture the process of the making
of a new individual, and follows the complex phenomena of
fecundation, of embryology, and post-embryonic develop-
ment, ,is it not impossible to conceive of the production of
two identical individuals ? In all the course of this develop-
ment, from the first cleavage of the fertilised egg-cell on,
it is practically impossible to repeat processes absolutely
identically, hence to produce absolutely identical organs,
parts, cells. Now the germ-cells have their very origin in
a repeated complex process, mitotic cell division; they are
produced as nearly alike as possible, but it is not possible
to make them absolutely identical.

Development, whether largely epigenetic or largely evo-
lutionary, depends at least partly (probably largely) on the
physical, i. e., structural, character of the germ-cells. Slight
differences in the germ-cells then would lead to considera-
ble differences in the fully developed organ. If the differ-
ences in the germ-cells happened, as would occasionally or
rarely be the case, to be considerable, then the differences in
the adults would be very considerable (mutations, sports,
monsters, etc.). We know enough of the complex and
epigenetic character of ontogeny to see plainly that identity
among individuals, even of the same brood, is impossible.

Variation, then, seems the necessary, the absolutely un-
avoidable outcome of the conditions to which the developing
individual is exposed. Indeed, all the individuals of a
species might start (as fertilised eggs) exactly alike, and
yet I cannot see how any two could come out alike. The
inevitable slight differences in position, and hence in nutri-
tion, in the results of the host of dividing and folding, in-
vaginating and evaginating processes, the relations of each
individual, whether in the mother's body or out of it, to
everything else outside of itself all these are conditions



386 DARWINISM TO-DAY.

bound to vary a little between any two individuals. And as
we know from the facts of experimental embryology that
development is, partly at least, epigenetic in character, i.e.,
depends on and is influenced by external factors, this in-
evitable variation in influencing conditions is bound to pro-
duce variations in the individuals.

Is there, indeed, any need at all for assuming (i) any
mysterious "tendency" of the germ-plasm to vary? and (2)
that the individual (continuous) variation depends wholly on
germ-plasm structure? Why cannot the simple fluctuating
or Darwinian variations be chiefly the result of the inevitable
variation in the epigenetic factors, which, when not intruded
on by exceptional disturbances, would themselves follow the
"law of error" and hence produce "law of error" varia'bil-
ity? All normal swingings of the variation pendulum in
any part or character, between long and short, large and
small, round and angular, smooth and rough, etc., etc.,
would result from the normal variation of the processes ; the
larger (extremes of range) variations being the fewer be-
cause the larger (extremes of range) variations in the
ontogenetic processes would be the fewer. Exceptionally
large epigenetic variations would produce exceptionally
large variations in the individual sports, mutations.

Klebs, 11 as a result of his masterly experimental studies
on modifications of plant development, comes to the
conclusion that the only proved causes of variation are
extrinsic influences stimulating, working through, or com-
bined with, intrinsic conditions (not vitalistic, but physico-
chemical). Similarly, Tower, 12 from his protracted studies
on the variations in certain insects, concludes that all these
variations are caused by external stimuli working on the
germ-plasm.

If variation is thus simply the wholly natural and un-
avoidable effect 1 ' of this inevitable non-identity of vital
process and environmental condition, why does not evolution



DARWINISM'S PRESENT STANDING. 3^7

possess in this state of affairs the much sought for, often
postulated, all-necessary, automatic modifying principle an-
tedating and preceding selection which must

A determinate

though not pnr- effect change, determinate though not purpose-
poseM change. ful ? Nageli's automatic perfecting principle is
aft impossibility to the thorough-going evolutionist seeking
for a causo-mechanical explanation of change. But an
automatic modifying principle which results in determinate
or purposive change, that is, in the change needed as the
indispensable basis for the upbuilding of the great fabric of
species diversity and descent ; is not that the very thing pro-
vided by the simple physical or mechanical impossibility of
perfect identity between process and environment in the case
of one individual and process and environment in the case
of any other ? It seems so to me.

But I do not know. Nor in the present state of our knowl-
edge does any one know, nor will any one know until, as
Brooks " says of another problem, we find out. We are
ignorant; terribly, immensely ignorant. And our work is,
to learn. To observe, to experiment, to tabulate, to induce,
to deduce. Biology was never a clearer or more inviting
field for fascinating, joyful, hopeful work. To question life
by new methods, from new angles, on closer terms, under
more precise conditions of control ; this is the requirement
and the opportunity of the biologist of to-day. May his
generation hear some whisper from the Sphinx !

APPENDIX.

1 One of the most serious and detailed critical analyses of the
selection theory, resulting in conclusions totally antagonistic to Dar-

Wigand's criti- wm i sm > is that of the Marburg botanist, Prof. Albert
cismoftheselec- Wigand, composing the three volumes entitled "Der
tion theories. Darwinismus und die Naturforschung Newtons und
Cuviers" (Vol. I, 1874; Vol. II, 1876; Vol. Ill, 1877). From the
"Announcements" at the beginning of each volume I quote as
follows :



3 88 DARWINISM TO-DAY.

From Vol. I. "Die hier dargebotene Kritik der Darwin' schen
Lehre weist zunachst durch eingehende Priifung der hierher ge-
horigen naturhistorischen Thatsachen nach, dass weder die Voraus-
setzungen, von denen die Theorie ausgeht, noch ihre Consequenzen
mit der wirklichen Natur iibereinstimmen, dass sie demnach den
Anforderungen an eine wissenschaftliche Hypothese nicht entspricht.
Vielmehr erweist sich dieselbe als eine philosophische Speculation,
welche nicht nur die unserer Naturerkenntniss vorgezeichneten
Grenzen iiberschreitet, sondern vor Allem die wichtigsten Grundsatze
der wahren Forschung, wie sie durch die grossen Meister aufgestellt
und in der bisherigen Entwickelung der Naturwissenschaft allgemein
anerkannt und unbedingt maassgebend gewesen sind, insbesondere
die Principien der Causalitat und der organischen Entwickelung, aufs
grobste verleugnet. Demnach erkennt das vorliegende Werk seine
Hauptaufgabe gerade darin, der bis dahin befolgten Forschungsweise
gegeniiber jener neuesten Naturphilosophie ihr Recht zu wahren."

From Vol. II. "Vermittelst der hierdurch gewonnenen Kriterien
gelangt die Untersuchung in Betreff des Darwinismus zu fol-
gendem Ergebnis: Derselbe geht nicht bloss von falschen Voraus-
setzungen aus, erweist sich nicht nur unfahig in Beziehung auf die
versprochenen Leistungen. ist nicht nur verfehlt durch die princi-
pielle Unmoglichkeit seiner Aufgabe, ist nicht nur eine der Natur-
forschung fremdartige, rein speculative Operation, sondern indem
derselbe das Princip der Causalitat und Entwickelung mit dem
Zufall und der Teleologie als Erklarungsgrunde vertauscht, erscheint
er als eine der Naturforschung in ihrer Fundamentalmaxime wider-
sprechende, darum dieselbe geradezu gefahrdende Verirrung, um
so mehr als er unter ihrer Maske auftritt. Der Darwinismus ist
einer jener Versuche. welche im Namen der Naturforschung die
Naturforschung verderben."

From Vol. III. "Der vorliegende dritte Band, mit welchem dieses
Werk abschliesst, hat zum Gegenstand nicht die dem Darwinismus
zu Grunde liegende Theorie, sondern die concrete Gestalt, in welcher
derselbe als eine fur unsere Zeit charakteristische culturhistorische
Thatsache in die Erscheinung tritt. Insbesondere wird versucht,
ein Bild von der Darwin'schen Schule als der Gesammtheit der die
Transmutationstheorie vertretenden Auctoren und von der Art und
Weise. wie sich die letztere im Lichte ihrer Bekenner darstellt, zu
entwerfen. Hierbei ergibt sich, dass der Darwinismus mehr in einer
iellosen Zeitstromung und in einer wissenschaftlich nicht motivirten
Stimmung der Geister als in einer bestimmt zu formulirenden Lehre
besteht, und dass derselbe bereits in seinem eigenen Lager in alien
wesentlichen Punkten wissenschaftlich tiberwunden ist, und zwar in
soldier Weise, dass in den widerstreitenden Ansichten der Darwin-



DARWINISM'S PRESENT STANDING. 389

ianer doch zugleich der Keim fur die allein richtige Auffassung der
organischen Natur, wenn auch grossentheils unklar und unbewusst,
verborgen liegt."

A special answer to this exhaustive pleading of Wigand is offered
by H. Spitzer in his "Beitrage zur Descendenztheorie und zur Metho-
dologie der Naturwissenschaft," 1886.

'" However, there still exist, especially in England, thorough-
going Darwinians who see nothing serious in all this criticism of
Lankester's their great compatriot's explanation of the origin of
upholding of species. Lankester, one of the most prominent of
Darwinism, English naturalists, said at York, last August (1906),
in his inaugural address as president of the British Association for
the Advancement of Science : "Under the title 'Darwinism' it is con-
venient to designate the various work of biologists tending to estab-
lish, develop or modify Mr. Darwin's great theory of the origin of
species. In looking back over twenty-five years it seems to me that
we must say that the conclusions of Darwin as to the origin of
species by the survival of selected races in the struggle for exist-
ence are more firmly established than ever. And this because there



Online LibraryVernon L. (Vernon Lyman) KelloggDarwinism to-day; a discussion of present-day scientific criticism of the Darwinian selection theories, together with a brief account of the principal other proposed auxilary and alternative theories of species-forming → online text (page 36 of 38)