the Lamarckian factors—are the lowest in position, most fundamental
in importance, and therefore most universal in their operation. They
are therefore also first in the order of time. They precede all other
factors and were _for a long time the only ones in operation_. For
observe: all the selective factors, viz. those of Darwin and Romanes,
are wholly conditioned on Reproduction; for the changes in the case of
these are not in the individual life but only in the offspring. And
not only so but they are also strictly _conditioned on sexual modes
of reproduction_. For all non-sexual modes of reproduction such as
fission and budding are but slight modifications of the process of
growth, and the resulting multitude of organisms may be regarded as in
some sense _only an extension of the first individual_. There is thus a
kind of immortality in these lowest protozoa. Of course therefore the
identical characters of the first individual are continued indefinitely
_except in so far as they are modified_ in successive generations by
the effect of the environment or by use and disuse of organs—i. e.
by _Lamarckian factors_. In sexual generation, on the contrary, the
characters of two diverse individuals are funded in a common offspring;
and the same continuing through successive generations, it is evident
that the inheritance in each individual offspring is infinitely
multiple. Now the tendency to variation in offspring is in proportion
to the multiplicity of the inheritance: for among the infinite number
of slightly different characters, as it were offered for inheritance in
every generation, some individuals will inherit more of one and some
more of another character. In a word, sexual generation, by multiple
inheritance, tends to variation of offspring and thus _furnishes
material for natural selection_.
Thus then I repeat, all the selective factors are absolutely dependent
for their operation upon sexual reproduction. _But there was a time
when this mode of reproduction did not exist._ It is certain the
non-sexual preceded the sexual modes of reproduction. I cannot stop
now to give the reasons for believing this. I have already given them
in some detail in a previous article[68] to which I would refer the
reader. Suffice it to say now that the order of introduction of the
various modes of reproduction culminating in the highest sexual modes
is briefly as follows: (1) _Fission._ An organism of the lowest kind
grows and divides into two. Each half grows to mature size and again
divides; and so on indefinitely. In this case there is no distinction
between parents and offspring. Each seems either or neither. (2)
_Budding._ Growth-force concentrating in one part produces a _bud_,
which continues to grow and individuate itself more and more until
it separates as a distinct individual. This is a higher form than
the last because in this case the individual is not sacrificed. Only
a small part separates and the separated part is in some sense an
_offspring_. We have therefore for the first time the distinction
of parent and offspring. (3) By the _law of differentiation and
localisation of functions_, the bud-forming function is next relegated
to a special place and we now have a bud-forming organ. (4) By another
general law, the law of _interior transfer_, the bud-forming organ is
next transferred for greater safety to an interior surface and thus
_simulates_ an ovary, although not yet a true ovary or _egg-forming_
organ. Examples of all these steps are found among existing animals.
[68] _Genesis of Sex, Pop. Sci. Monthly_, 1879, Vol. xvi. p.
167. _Revue Scientifique_, Feb. 14, 1880.
Thus far reproduction is non-sexual. But now comes the great step,
i. e. the introduction of sexual reproduction, in its lowest forms.
(5) This simulated ovary or bud-forming organ becomes a true ovary or
egg-forming organ; or rather, at first, a combination of ovary and
spermary. The same organ prepares two kinds of cells, male and female,
germ-cell and sperm-cell, which by their union produce an egg which
develops into an offspring; and not only an offspring in the sense of
a separated part of a previous individual, but in some sense a new
creature, the creation of a _new individual_. There is an enormous
difference and even contrast between this and all preceding modes. In
non-sexual modes one individual becomes two; in this, two individual
cells unite to form one. It is an expensive, even wasteful mode unless
attended with some great advantage. The nature of this advantage we
will presently see.
Thus far we have given only the lowest form of sexual generation. The
two sexual _elements_ only, germ-cell and sperm-cell are separated
from each other, but not yet even the sexual organs, ovary and
spermary, much less the sexual individuals, male and female. (6) The
sex-element-forming function is next differentiated and localised in
two different organs, ovary and spermary, but not yet in two different
individuals. This is hermaphroditism so common in plants and in lower
animals. (7) The already separated sexual organs are next localised in
different individuals, and we now have male and female individuals.
This is the case in many plants and in all the higher animals. (8) And
finally these male and female individuals become more and more diverse
in character.
The object of this whole process of separation, first of the elements,
then of the organs, then of the individuals, and last the increasing
divergence of the individuals, is undoubtedly the funding of more and
more diverse characters in a common offspring; and thus by increasing
multiplicity of inheritance to insure larger variation in offspring and
thereby furnish more abundant material for natural selection. This is
far more than a compensation for the apparent wastefulness of this mode
of reproduction.
If then the non-sexual preceded the sexual modes of reproduction,
evidently, _at first, only Lamarckian factors could operate_. Evolution
was then carried forward wholly by changes in the individual produced
by _the environment_ and by _use and disuse of organs_, continued and
increased through successive generations indefinitely. It is probable
therefore that for want of the selective factors, the rate of evolution
was at first comparatively slow; unless indeed, as seems probable, the
earliest forms were, as the lowest forms are now, more plastic under
pressure of physical conditions than are the present higher forms.
The great contrast between the Lamarckian and Darwinian factors in
this regard, and the slowness of change _now_ in higher forms under
_Lamarckian factors alone_, is best shown in plants where either kind
of factors may be used at pleasure. In these, if we wish to _make_
varieties, we propagate by seeds—sexual reproduction—but if we wish
to _preserve_ varieties, we propagate by buds and cuttings—non-sexual
reproduction.
We have taken the two Lamarckian factors together, in contrast with
the Darwinian. But even in the two Lamarckian factors there is a great
difference in grade. Undoubtedly the lowest and first introduced was
pressure of the _physical environment_. For even _use and disuse_
of organs implies some degree of volition and voluntary motion, and
therefore already some advance in the scale of evolution.
With the introduction of sex another entirely different and higher
factor was introduced, viz. _natural selection_, among a varying
progeny, of the fittest individuals. We have already seen how sexual
generation produces variation of offspring and how this furnishes
material for natural selection. As soon, therefore, as this form
of generation was evolved, this higher factor came into operation,
and immediately, as it were, _assumed control_ of evolution, and
the previous factors _became subordinate_ though still underlying,
conditioning, modifying the higher. The result was an immediate
increase in the speed and in the diversity of evolution. It is very
worthy of note too, that it is in the higher animals, such as birds
and mammals, where we find the highest form of sexual generation,
where the diversity of funded characters and therefore the variation
in the offspring is the greatest, and natural selection most active:
it is precisely among these that the Lamarckian factors are most
feeble, because during the most plastic portion of life the offspring
is removed from the influence of the physical environment and from the
effects of use and disuse, by their enclosure within the womb or within
a large egg well supplied with nourishment. In these, development is
already far advanced before Lamarckian factors can operate at all.
Next I suppose _Physiological selection_ or Romanes's factor came into
operation. After the introduction of sex, it became necessary, that the
individuals of some varieties should be in some way _isolated_, so as
to prevent the swamping of varietal characters as fast as formed, in a
common stock by cross breeding. In very low forms with slow locomotion,
such isolation might easily take place accidentally. Even in higher
forms, changes in physical geography or accidental dispersion by winds
and currents, would often produce _geographical isolation_; and thus
by preventing crossing with the parent stock, secure the formation of
new species from such isolated varieties. But in order to insure in
all cases the preservation of commencing species, _sexual isolation_
was introduced or evolved as I suppose later, and according to Romanes
somewhat as follows:
All organs are subject to variation in offspring, but none are so
sensitive in this regard as the reproductive organs; and these in no
respect more than in relative fertility under different conditions.
Suppose then the offspring of any parent to vary in many directions.
By cross-breeding among themselves and with the parent stock, these
are usually merged in a common type, their differences pooled, and the
species remains fixed or else advances slowly by natural selection,
along _one line_, as physical conditions change in geological time. But
from time to time there arises a variation in the reproductive organs
of some individuals, of such kind that these individuals are fertile
among themselves, but sterile or less fertile with other varieties
and with the parent stock. Such individuals are _sexually isolated_
from others, or _sexually segregated_ among themselves. Their varietal
differences of all kinds are no longer swamped by cross-breeding, but
go on to increase until they form a new species. It is evident then,
as Romanes claims, that natural selection alone tends to _monotypal_
evolution. Isolation of some sort seems necessary to _polytypal_
evolution. The tree of evolution under the influence of natural
selection alone grows palm-like from its terminal bud. Isolation was
necessary to the starting of lateral buds, and thus for the _profuse
ramification_ which is its most conspicuous character.
Next, I suppose, was introduced, _sexual selection_, or contest
among the males by battle or by display, for the possession of the
female, the success of the strongest or the most attractive, and the
perpetuation and increase of these superior qualities of strength
or beauty in the next generation. This I suppose was later, because
connected with a higher development of the psychical nature. This is
especially true when beauty of color or song determines the selection.
As might be supposed therefore, this factor is operative only among the
highest animals, especially birds and mammals, and perhaps some insects.
Next and last, and only with the appearance of man, another entirely
different and far higher factor was introduced, viz. _conscious,
voluntary co-operation in the work of evolution_—a conscious voluntary
_effort to attain an Ideal_. As already said, we call this a factor,
but it is much more than a factor. It is another nature working in
another world—the spiritual—and like physical nature using all
factors, but in a new way and on a higher plane. In early stages man
developed much as other animals, unconscious and careless whither he
tended and therefore with little or no voluntary effort to attain a
higher stage. But this voluntary factor, this striving toward a goal
or ideal, in the individual and in the race, increased more and more
until in civilised communities of modern times it has become by far the
dominant factor. Reason, instead of physical nature, takes control,
though still using the same factors.
Now, in this whole process, we observe two striking stages. The one is
the introduction of Sex, the other the introduction of Reason.[69] They
might be compared to two equally striking stages in the evolution of
the individual, viz. the moment of _fertilisation_ and the moment of
_birth_. As the ontogenic evolution receives fresh impulse at the two
moments of fertilisation and of birth; so the evolution of the organic
kingdom at the two periods mentioned. With the appearance of _sex_,
three new and higher factors are introduced, and these immediately
assumed control and quickened the rate of evolution. With the
appearance of reason in man another and far higher factor is introduced
which in its turn assumes control, and not only again quickens the
rate, but elevates the whole plane of evolution. This voluntary,
rational factor not only assumes control itself, but transforms all
other factors and uses them in a new way and for its own higher
purposes.
[69] By Reason I mean the faculty of dealing with the
phenomena of the inner world of consciousness and ideas, or
_reflection_ on the facts of consciousness. Animals live in
_one_ world, the outer _world of sense_; man in _two_ worlds,
in the outer world like animals, but also in the inner and
higher _world of ideas_. All that is characteristic of man
comes of this capacity of dealing with this inner world. In
default of a better word I call it Reason. If any one can
suggest a better word I will gladly adopt it.
This last is by far the greatest change which has ever occurred in
the history of evolution. In organic evolution nature operates by
necessary law without the voluntary co-operation of the thing evolving.
In human progress man voluntarily co-operates with nature in the work
of evolution and even assumes to take the process mainly into his
own hands. Organic evolution is by _necessary_ law, human progress
by _free_, or at least by _freer_, law. Organic evolution is by a
_pushing_ upward and onward from below and behind, human progress by
an aspiration, an attraction toward an ideal—a _pulling_ upward and
onward from above and in front.
This great change may well be likened to a _birth_.[70] Spirit or
Reason or the Psyche—call it what you like—was in embryo in animals
in increasing degrees of development through all geological times
and came to birth and capacity of free activity, became free spirit
investigating its own phenomena in man. In animals the evolution of
Psyche was the unconscious result of organic evolution. In man the
Psyche is _born_ into a new world of freer activity and undertakes to
develop itself.
[70] See _Evolution and its Relation to Religious Thought_,
Part iii. Chap. iv, where the writer's views are more fully
brought out.
It may be well to stop a moment and show briefly some of the striking
differences between organic and human evolution, differences resulting
wholly from the introduction of this new factor, or rather this
evolution on a new and higher plane.
(1) In organic evolution the fittest are those most in _harmony with
the environment_ and therefore they _survive_. In human evolution
the fittest are those most _in harmony with the ideal_, and often,
especially in the early stages of evolution, during the dominance of
natural selection, they _do not survive_ because not in harmony with
the social environment.
(2) In organic evolution the weak, the helpless, the unfit in any way,
_perish_, and ought to perish, because this is the most efficient way
of _strengthening the blood_, or _physical_ nature. In human evolution
the weak, the helpless, the physically unfit, are _sustained_, and
ought to be sustained, because sympathy, love, pity _strengthens
the spirit or moral nature_. But the spirit or moral nature is also
sustained by, and conditioned on, the physical nature. In all our
attempts therefore to help the weak we must be careful that we avoid
poisoning the blood and weakening the physical health of the race. This
we believe can and will be done by _rational education_, physical,
mental, and moral. We only allude to this. It is too wide a subject to
follow up here.
(3) In organic evolution the _form must_ continually _change_ in order
to keep in harmony with the changing environment. In other words
evolution is by constant _change of species_, genera, etc.; there must
be a continual evolution of _new forms_. In human evolution, and more
and more as civilisation goes on, man modifies the environment so as to
bring it in harmony with himself and his wants, and therefore there is
_no necessity for_ change of form or _making of new species of man_.
Human evolution is not by modification of _form_—new species, but by
modification of spirit—new planes of activity.
(4) In organic evolution as a higher factor arises it assumes control,
and previous factors sink into subordinate position. But in human
evolution the rational factor not only assumes control but transforms
all other factors, using them in a new way and for its own higher
purposes. Thus the Lamarckian factor—_environment_—is modified and
even changed so as to affect suitably the human organism. This is
_Hygiene_ or _Sanitation_. Again, the various organs of the body and
faculties of the mind are deliberately _used_ (another Lamarckian
factor) in such wise as to produce their highest efficiency. This
is _education_, or _training_, physical, mental, moral. So also the
selective factors are similarly transformed, and natural selection
becomes rational selection. This is freely applied to domestic animals
and with limitations imposed by reason itself will be applied to man.
(5) The way of evolution toward the highest, i. e. from Protozoa to
man and from lowest man to the ideal man, is a _very narrow way_, and
few there be that find it. In the case of organic evolution it is _so_
narrow, that once get off the track and it is impossible to get on
again. No living form of animal is now on the way to form man, can by
any possibility develop manward. They are all gone out of the way. They
are all off the trunk line. The golden opportunity is past. The tree of
evolution is an _excurrent_ stem continuous to the terminal shoot—man.
Once leave the main stem as a branch, it is easy to continue growing in
the direction chosen, but impossible to get back again on the straight
upward way to the highest. In human evolution whether individual or
racial, the same law holds, but with a difference. If an individual or
a race gets off from the straight and narrow way toward the highest,
the Divine ideal, it is _hard_ to get back on the track; hard but
not _impossible_. Man's own effort is the chief factor in his own
evolution. By virtue of his self-activity, and through the use of
reason, man alone is able to rectify an error of direction and return
again to the deserted way.
REFLECTIONS ON THE ABOVE PRINCIPLES AND THEIR APPLICATION TO SOME
QUESTIONS OF THE DAY.
I.
Just now there is much controversy in regard to the factors of
evolution. Both Darwin and Spencer, the two greatest expounders of the
modern theory of evolution, acknowledge and insist upon at least four
factors; viz. the two Lamarckian and the two distinctively Darwinian.
The only difference between them is in the relative importance of
the two sets; Spencer regarding the former and Darwin the latter
as the more potent. But some late Darwinians have gone far beyond
Darwin himself in their estimate of the power of the most distinctive
Darwinian factor, viz. natural selection. Weismann and Wallace have
each written a book, and Lankester many excellent articles to show that
natural selection is the one sole and sufficient cause of evolution,
that changes during the individual life whether by effect of the
environment or by the use and disuse of organs _are not inherited at
all_, that Lamarck was wholly wrong and that Darwin (in connection
with Wallace) is the sole founder of the true theory of evolution, and
finally that Darwin himself was wrong only in making any terms whatever
with Lamarck.
The argument for this view has, perhaps, been most strongly put
by Weismann and is based partly on experiments, but mainly on his
ingenious and now celebrated theory of the _immortality of germ-plasm_.
The animal body consists of two kinds of cells wholly different in
function, somatic cells and germ-cells, including in this last the
sexual elements both male and female. Somatic cells are modified and
specialised for the various functions of the body; germ-cells are
wholly unmodified. The somatic cells are for the conservation of the
_individual_ life, germ-cells for the conservation of the _species_.
Now according to Weismann, _inheritance is only through germ-cells_.
Environment affects only the somatic cells and therefore changes
produced by environment cannot be inherited. Sexual generation was
introduced for the purpose of producing variability in progeny and
thus furnishing material for natural selection, as this was the only
means of evolutionary advance. Weismann made many experiments on
animals, especially by mutilation, to show that somatic changes are not
inherited.
We shall not argue this question but content ourselves with making
three brief remarks.
1. If the views presented in this article be true, then the Lamarckian
factors must be true factors, because _there was a time when there
were no others_. They were necessary therefore to start the process of
evolution, even if no longer necessary at present.
2. But if the Lamarckian factors were ever operative, _they must be so
still_, though possibly in a subordinate degree. A lower factor is not
abolished, but only becomes subordinate to a higher factor when the
latter is introduced. Thus it may well be that Lamarckian factors are
comparatively feeble at the present time and among present species,
especially of the higher animals, and yet not absent altogether. In
the earliest stages of evolution there was a complete _identification
of germ-cells and somatic cells_—of the individual with the species.
In such cases, of course, the effect of environment must be inherited
and increased from generation to generation. But the differentiation of
germ and somatic cells was not all at once; it was a _gradual process_,
and therefore the effect of the environment _on the germ-cells through
the somatic cells_ must have continued, though in decreasing degree,
and still continues. The differentiation is now, in the higher animals,
so complete that germ-cells are probably not at all affected by changes
in somatic cells, unless these changes are _long continued in the same
direction and are not antagonised by natural selection_.