Modern philanthropy--so far at least as it ever studies ultimate
results--constantly relies on this ill-founded belief as its
justification for ignoring the warnings of those who point out the
ultimately disastrous results of a systematic defiance or reversal of
the great law of natural selection. This reliance finds strong support
in Mr. Spencer's latest teachings, for he holds that the inheritance of
the effects of use and disuse takes place universally, and that it is
now "the chief factor" in the evolution of civilized man (pp. 35, 74,
iv)--natural selection being quite inadequate for the work of
progressive modification. Practically he abandons the hope of evolution
by natural selection, and substitutes the ideal of a nation being
"modified _en masse_ by transmission of the effects" of its institutions
and habits. Use-inheritance will "mould its members far more rapidly and
comprehensively" than can be effected by the survival of the fittest
alone.
But could we rely upon the aid of use-inheritance if it really were a
universal law and not a mere simulation of one? Let us consider some of
the features of this alleged factor of evolution, seeing that it is
henceforth to be our principal means of securing the improvement of our
species and our continued adaptation to the changing conditions of a
progressive civilization.
It is curiously uncertain and irregular in its action. It diminishes or
abolishes some structures (such as jaws or eyes) without correspondingly
diminishing or abolishing other equally disused and closely related
parts (such as teeth, or eye-stalks). It thickens ducks' leg-bones while
allowing them to shorten. It shortens the disused wing-bones of ducks
and the leg-bones of rabbits while allowing them to thicken; and yet in
other cases it greatly reduces the thickness of bones without shortening
them. It transmits tameness most powerfully in an animal which usually
cannot acquire it. It aids in webbing the feet of water-dogs, but fails
to web the feet of the water-hen or to remove the web in the feet of
upland geese.[72] It allows the disused fibula to retain a potentiality
of development fully equal to that possessed by the long-used tibia. It
lengthens legs because they are used in supporting the body, and
shortens arms because they are used in pulling. Whether it enlarges
brain if used in one way and diminishes it if used in another, we cannot
tell; but it must obviously deaden nervous sensibilities in some cases
and intensify them in others. It enlarges hands long before they are
used, and thickens soles long before the time for walking on them. At
the same time, as if by an oversight, it so delays its transmission of
the habit of walking on these thickened soles, that the gradual and
tedious acquisition of the non-transmitted habit costs the infant much
time and trouble and often some pain and danger. Yet where aided by
natural selection, as with chickens and foals, it transmits the habit in
wonderful perfection and at a remarkably early date. It transmits new
paces in horses in a single generation, but fails to perpetuate the
songs of birds. It modifies offspring like parents, and yet allows the
formation of two reproductive types in plants, and of two or more types
widely different from the parents in some of the higher insects. It is
said to be indispensable for the co-ordinated development of man and the
giraffe and the elk, but appears to be unnecessary for the evolution and
the maintenance of wonderful structures and habits and instincts in a
thousand species of ants and bees and termites. It is the only possible
means of complex evolution and adaptation of co-operative parts, and yet
in Mr. Spencer's most representative case it renders such important
parts as teeth and jaws unsuited for each other, and is said to ruin the
teeth by the consequent overcrowding and decay. It survives amidst a
general "lack of recognised evidence," and only seems to act usefully
and healthily and regularly in quarters where it can least easily be
distinguished from other more powerful and demonstrable factors of
evolution. So little does it care to display its powers where they would
be easily verifiable as well as useful that practical breeders ignore
it. So slight is its independent power that it seems to allow natural
selection or sexual selection or artificial selection to modify
organisms in sheer defiance of its utmost opposition, just as readily as
they modify organisms in other directions with its utmost help. If it
partially perpetuates and extends the pecked-out indentations in the
motmot's tail feathers, it on the other hand fails to transmit the
slightest trace of mutilation in an almost infinite number of ordinary
cases, and even where the mutilation is repeated for a hundred
generations; and it apparently repairs rather than transmits the
ordinary and oft-repeated losses caused by plucking hair, down and
feathers, and the wear and tear of claws, teeth, hoofs and skin.
It is often mischievous as well as anomalous in its action. Under
civilization with its division of labour, the various functions of mind
and body are very unequally exercised. There is overwork or misuse of
one part and disuse and neglect of others, leading to the partial
breakdown or degeneration of various organs and to general deterioration
of health through disturbed balance of the constitution. The brain, or
rather particular parts of it, are often over-stimulated, while the body
is neglected. In many ways education and civilization foster nervousness
and weakness, and undermine the rude natural health and spirits of the
human animal. Alcohol, tobacco, tea, coffee, extra brain work, late
hours, dissipation, overwork, indoor life, division of labour,
preservation of the weak, and many other causes, all help to injure the
modern constitution; so that the prospect of cumulative intensification
of these evils by the additional influence of use-inheritance is not an
encouraging one. It is true that modern progress and prosperity are
improving the people in various respects by their direct action; but if
use-inheritance has any share in effecting this improvement it must also
transmit increased wants and more luxurious habits, together with such
evils as have already been referred to. As depicted by its defenders,
use-inheritance transmits evils far more powerfully and promptly than
benefits. It transmits insanity and shattered nerves rather than the
healthy brain which preceded the breakdown. It perpetuates, and
cumulatively intensifies, a deterioration in the senses of civilized
men, but it fails to perpetuate the rank vigour of various plants when
too well nourished, or the flourishing condition of various animals when
too fat or when tamed. It already transmits the short-sight caused by so
modern an art as watchmaking, but so fails to transmit the
long-practised art of seeing (as it does of walking and talking) that
vision is worse than useless to a man until he gradually acquires the
necessary but non-transmitted associations of sensation and idea by his
own experience. In a well-known case, a blind man on gaining his sight
by an operation said that "all objects seemed to touch his eyes, as what
he felt did his skin"--so little had the universal experience of
countless ages impressed itself on his faculties. Under normal healthy
conditions use-inheritance is so slow in its action that "several
generations" must elapse before it produces any appreciable effect, and
then that effect is only precisely what selection might be expected to
bring about without its aid. Strong for evil and slow for good, it can
convey epilepsy promptly in guinea pigs, but transmits the acquirements
of genius so poorly that our best student of the heredity of genius has
to account for the frequent and remarkable deterioration of the
offspring by a theory which is strongly hostile to use-inheritance. It
would tend to make organisms unworkable by the excessive differences in
its rate and manner of action on co-operative parts, and by adapting
these parts to the total amount of nourishment received rather than to
occasional necessity or actual usefulness. It would tend to stereotype
habits and convert reason into instinct.
How then can we rely upon use-inheritance for the improvement of the
race? Even if it is not a sheer delusion, it may be more detrimental as
a positive evil than it is advantageous as an unnecessary benefit; and
as a normal modifying agent it is miserably weak and untrustworthy in
comparison with the powerful selective influences by which nature and
society continually and inevitably affect the species for good or for
evil. The effects of use and disuse--rightly directed by education in
its widest sense--must of course be called in to secure the highly
essential but nevertheless _superficial, limited, and partly deceptive_
improvement of individuals and of social manners and methods; but as
this artificial development of already existing potentialities does not
directly or readily tend to become congenital, it is evident that some
considerable amount of natural or artificial selection of the more
favourably varying individuals will still be the only means of securing
the race against the constant tendency to degeneration which would
ultimately swallow up all the advantages of civilization. The selective
influences by which our present high level has been reached and
maintained may well be modified, but they must not be abandoned or
reversed in the rash expectation that State education, or State feeding
of children, or State housing of the poor, or any amount of State
socialism or public or private philanthropy, will prove permanently
satisfactory substitutes. If ruinous deterioration and other more
immediate evils, are to be avoided, the race must still be to the swift
and the battle to the strong. The healthy Individualism so earnestly
championed by Mr. Spencer must be allowed free play. Open competition,
as Darwin teaches, with its survival and multiplication of the fittest,
must be allowed to decide the battle of life independently of a foolish
benevolence that prefers the elaborate cultivation and multiplication of
weeds to the growth of corn and roses. We are trustees for the countless
generations of the future. If we are wise we shall trust to the great
ruling truths that we assuredly know, rather than to the seductive
claims of an alleged factor of evolution for which no satisfactory
evidence can be produced.