Lamarckism And Neo-lamarckism





The "Lamarckian" view as opposed to the Darwinian continues to hold its

own, and indeed is more ardently supported than ever. On this view,

evolution has been accomplished not by a laborious selection of the best

which chanced to present itself--a selection in relation to which organisms

remained passive, but rather through the exertions of the organisms

themselves. It has been especially through the use and exercise of the

various organs in response to the requirements of life, through the

increased exercise of physical and mental functions, that the organism has

adapted itself more diversely and more fully to the conditions of its

life. What one generation acquired in differentiation of structure, in

capacities and habits, through its own exertions, it handed on to the

next. By cumulative inheritance there ultimately arose the fixed specific

characters, and the diversity and progressive gradations of organisms have

gone hand in hand with an ever increasing activity. And as with the

physical so it has been with the mental. Through continual use and

exercise of the functions their capacity has been increased and modified.

Through the frequent repetition of voluntary actions necessary to life the

habitual use of them has come about. Habits that have become fixed are

correlated with habitual psychical predispositions. These, gradually

handed on by inheritance to the descendants, have resulted in the

marvellous instincts of animals. Instinct is inherited habit that has

become fixed. Corresponding to this there is on the other hand the

recognition--in theory at least--that the disuse of an organ, the

non-exercising of a function leads to degeneration of structure and so

co-operates in bringing about a gradual but persistent modification of the

features and constitution of organisms.



These views, which have grown out of Lamarck's fundamental ideas

("Philosophie zoologique," 1809) are now usually associated with the

theory advanced chiefly by Etienne Geoffrey St. Hilaire ("Philosophie

zoologique," 1830), the opponent of Cuvier, and the ally of Goethe, of the

direct influence of the monde ambiant. The "surrounding world," the

influences of climate, of locality, of the weather, of nutrition, of

temperature, of the salinity of the water, of the moisture in the air, and

all other conditions of existence, influence the living organism. And they

do so not indirectly, as is implied in the process of selection, simply

playing the part of a sieve, and not themselves moulding and transforming,

but directly by necessitating the production of new developments in the

living substance, new chemical and physiological activities, new groupings

and changes of form, and new organs.



Darwin himself did not regard these two theories as opposed to the theory

of selection, but utilised them as subsidiary interpretations. It is

obvious, however, that at bottom they conceal an essentially different

fundamental idea, which, if followed out to its logical consequences,

reduces the "struggle for existence" to at most a wholly indifferent

accessory circumstance. Weismann felt this, and hence his entirely

consistent endeavours to show by great examples, such as the origin of

flowers, the mutual adaptations of flowers and insects, the phenomena of

mimicry, and many other cases, that neither the Lamarckian nor any other

factor in evolution, except only natural, passive selection, suffices as

an interpretation. From the Darwinian standpoint he is absolutely right,

and must needs speak of the "omnipotence of natural selection," for it

must either be omnipotent, or it must give place to the other two factors,

and retain only the significance we attributed to it in another connection

(p. 157), which amounts to saying none at all. It is obvious enough why

the discussion as to these factors should centre round the question of the

"inheritance of acquired characters," "acquired" either through the use or

disuse of organs, the exercise or non-exercise of functions, or through

the stimuli of the external world.



The neo-Lamarckian conflict with Darwinism has become more and more acute

in recent times, and the neo-Lamarckians have sometimes passed from

contrasting rival interpretations to excluding the Darwinian factor

altogether. As the particular champion of the neo-Lamarckian view, we must

name Th. Eimer, the recently deceased Tuebingen zoologist. His chief work

is in three volumes, entitled "Die Entstehung der Arten auf Grund von

Vererbung erworbener Eigenschaften, nach Gesetzen organischen

Wachsens."(43) It is a polemic against Weismannism in all details, even to

the theory of "germinal selection." Eimer follows in the footsteps of St.

Hilaire, and shows what a relatively plastic and sensitive creature the

organism is to the surrounding world, the conditions of nutrition and

other such influences. There is in this connection a particularly

instructive chapter on the physiological and other variations brought

about by external influences which act as "stimuli of the nervous system."

The whole theory of Lamarck and St. Hilaire transcends--notwithstanding the

protests of Eimer to the contrary--the categories of the mechanical theory

of life, and this chapter does so in particular. The array of facts here

marshalled as to the spontaneous self-adaptation of organisms to their

environment--in relation to colour mainly--forms the most thoroughgoing

refutation of Darwinism that it is possible to imagine. It is shown, too,

by a wealth of examples from osteology, how use (and the necessities of

the case--a consideration which again goes beyond the bounds of mere

Lamarckism) may modify, increase or diminish vertebrae, ribs, skull and

limbs, in short, the whole skeleton.



Kassowitz is equally keen and convinced in his opposition to natural

selection, and in his comprehensive "Allgemeine Biologic"(44) he attacks

orthodox Darwinism from the neo-Lamarckian standpoint. The whole of the

first volume is almost chapter for chapter a critical analysis, and the

polemical element rather outweighs his positive personal contribution. He

criticises very severely all attempts to carry the Darwinian principle of

explaining adaptations into internal and minute details, arguing against

Roux's "Struggle of Parts" and Weismann's "Germinal Selection." And though

he himself maintains very decidedly that the ultimate aim of biology is to

find a mechanical solution of the problem of life, he criticises the

modern hypotheses in this direction without prejudice, and declares them

unsuccessful and insufficient, inclining himself towards the

"neo-vitalistic reaction" in its most recent expression. Along with Eimer

and Kassowitz, we may name W. Haacke, especially in relation to his views

on the acquisition and transmission of functional modifications and his

thoroughgoing denial of Darwinism proper. But his work must be dealt with

later in a different connection.(45)



These neo-Lamarckian views give us a picture of the evolution of the world

that is much more convincing than the strictly Darwinian one. Instead of

passive and essentially unintelligent "adaptation" through the sieve of

selection, we have here direct self-adaptation of organisms to the

conditions of their existence, through their own continual restless

activity and exertion, an ascent of their own accord to ever greater

heights and perfections. A theory of this kind might easily form part of a

religious conception of the world. We might think of the world with

primitive tendencies and capacities, in which the potentialities of its

evolution were implied, and so ordered that it had to struggle by its own

exertions to achieve the full realisation of its possibilities, to attain

to ever higher--up to the highest--forms of Being. The process of nature

would thus be the direct anticipation of what occurs in the history of man

and of mind. And the task set to the freedom of individual men, and to

mankind as a whole, namely, to work out their own nature through their own

labour and exertion, and to ascend to perfection--this deepest meaning of

all individual and collective existence--would have its exact prelude and

preparation in the general nature and evolution of all living creatures.

The transition from these theories of nature to a teleological outlook

from the highest and most human point of view is so obvious as to be

almost unavoidable. And although a natural science which keeps to its own

business and within its own boundaries has certainly no right to make this

transition for itself, it has still less right to prevent its being made

outside of its limits.





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