INITIAL VARIATIONS AND TOTAL EXPERIENCE.
The present chapter is on _a priori_ lines and will perhaps be
dismissed with a wave of the hand or hurriedly skimmed over, but I pray
the reader at least to read the two or three last pages of it. It is
at any rate suggestive, and perhaps I may anticipate the comments of
the neo-Darwinian and throw myself on his mercy by mentioning a remark
of the late Sir Andrew Clark, prince of physicians and genial cynic,
which he made to a patient in my presence. A lady not distinguished for
depth of thought asked him a rather silly question in medicine. As if
offended he drew himself up, holding in his hand a cup of tea which he
was enjoying, and replied at once “Madam, you must get a younger and
more inexperienced man than I am to answer you that question.”
A very high degree of probability may be attached to the presupposition
that Lamarckian factors, even in their humblest form, may enter into
the story of the organisms as historical and living beings. Every
hypothesis in matters of science, or, to put it at its lowest, every
scientific guess must transcend the evidence at the time available.
Total Experience.
The suggestion I venture to make here is that if we take a
comprehensive view of certain two great groups of phenomena in nature,
which may be termed universal in their extent, it is difficult to
conceive that they are not causally connected in the sense that one
is the universal antecedent of the other. On the one hand are found
universal minute differences, not only between any pair of organisms,
but of any two corresponding parts of any organism, even to the size
and shape of each leaf on each plant. On the other is universal
discontinuity of _total experience_ of all organisms. This term
includes all the stimuli of use and environment to which an organism
is exposed throughout its whole existence, and its response to them.
It includes the whole succession of active and passive stimuli which
begin with the formation of a zygote in higher forms, for example, and
continue till the death or end of reproductive life of the individual.
It stands for such stimuli as arise from _habitat_ on or in the
earth, in various levels of salt or fresh water, in sea, lake, pool
and river, and in the branches of trees, from _climate_, from degrees
of _light_, _temperature_, _moisture_ and _wind_, from presence and
activity of _enemies_ and _rivals_, from _supplies of food_, from
_geographical_ and _topographical_ position. Such an enumeration of
stimuli might be much extended if it would serve any purpose. But it is
enough to say that the number of such stimuli, and the varying degrees
in which these are received and responded to, have hardly any limit
which we can conceive. It is a very different and harder task to find
out the proportion in which such stimuli are advantageous, injurious
or indifferent to the organisms, but it may be taken as certain that
the vast majority are indifferent in the sense of producing structural
change, and, that the advantageous stimuli transmit structural effects
to offspring, is only a matter of very strong probability. If the above
two groups of phenomena are not causally connected they are intertwined
with remarkable closeness and perversity. This aspect of the “web of
life” has received attention, and deserves more.
Discontinuous Environments.
Some reference must be made here to observations of Prof. Bateson in
his work on variation. In the first place he makes a most valuable
statement that “_the environment as the directing cause is essential
to Lamarck’s theory and as the limiting cause is essential to the
doctrine of Natural Selection_”[36] (which I venture to place in
italics on account of its importance to all who seek the pathway of
organic evolution) and points out also that “diversity of environment
is thus the measure of diversity of specific form. Here then we meet
the difficulty that diverse environments often shade into each other
insensibly and form a continuous series.”[37] This is clearly true
and important to the subjects he is discussing. But in regard to the
conception with which I am here concerned, that of _total experience_
of organisms, it must be remembered that there is no such thing as an
environment apart from the living beings that it environs, and that
from this point of view there is no such thing in the world of nature
as a continuous environment. The environment of two amœbæ living under
a cover-glass is, for them, far from continuous. In their infinitesimal
existence the exact position they occupy in the environing drop of
fluid, in which the proportion of their humble fare at one side of the
cover-glass is not the same as that on the opposite side, renders
their environments discontinuous, or different from that of another
amœba occupying a position and “environment” which _we_ should consider
identical. And this consideration applies to the other few “tropisms”
which enter into their little lives. This statement may be difficult
to prove, but it is a necessity of thought. An illustration may assist
one in visualizing such discontinuity. A fly is seen crawling at its
own pace up one of the great pillars of St. Paul’s Cathedral. It comes
to one of the thin layers of cement worn down with age and so delicate
that a man can just see it in a good light. The fly pauses, and passes
into what is for it a chasm, with as much relative deliberation as the
man would show in passing across a deep railway cutting. The number of
pictures that could be made of cases corresponding to that of the amœba
is incalculable. A few will suffice. Two plants of the common nettle
are growing on the south side of a ditch in a lane, one rooted a foot
higher than the other. The upper one receives throughout its life from
wind and sun stimuli slightly different from those received by the
lower, and from the soil slightly less moisture. These again receive
stimuli very different from another pair on the northern side of the
lane. Again in windy weather a clump of sycamores facing the south-west
in England, and situated on the ridge of an eminence, will receive
very different stimuli from a similar clump on the north-eastern slope
of this eminence, and will demonstrate the fact, as to force of wind,
by a marked slope to the North East. Even in either of the clumps the
individual trees present varying degrees of slope according to their
position. The total experience of these two clumps of sycamores and
of any two in each clump is obviously different. In a windy situation
you can tell in July which is the prevailing wind by noting the main
inclination of the ears of corn in a field. Again two male sticklebacks
in a pond will make nests for the eggs, there to be deposited, and one
will choose a spot on the southern and another on the northern side of
a little promontory of soil and stones at the edge of the pond. One
will find ready for him materials for building his nest different from
those of his rival, and he and his wife and family will receive for
that season very different stimuli, and so will the stimuli differ in
other phases of their existence in a pond occupying a few square yards.
On a sandy bank in a garden facing south you may discover two little
caves ingeniously hidden by a small opening, and in each of them you
can see a toad. Though these are only a few feet apart one is more
widely open to sun and wind than the other and one deeper than the
other, and whatever the other activities of the two toads may be in
their little shelters, they receive stimuli different in strength and
number. On another bank in the same garden less exposed to view, and
altogether more sheltered from sun and wind and enemies, a robin has
built a well-hidden nest. If the six fledglings in the nest are watched
when the mother is absent they are seen to occupy very different
positions of comfort, pressure and warmth. When the mother-bird returns
from marketing she is hardly impartial in the amount of food she
puts into their open beaks. But the slight and perhaps unimportant
inequality of their experiences as fledglings is nothing to that which
follows when they fly abroad, and which continues to the end of their
lives, the life of a robin being somewhere about ten years long. The
differences of the _total experience_ of the six young robins is easy
to picture. Again, surely, the total experience of two fleas on the
body of one plague-rat must be for such small creatures of importance
to their welfare, according as their respective “pitches” are on the
abdomen, back or legs of the host. When the life-history of a human
being is told in full the discontinuity of his total experience needs
no proof. The proof is written large before our eyes. But, perhaps, one
example may be given. There are two very eminent living writers, whose
light has certainly for some years not been hidden under a bushel, Mr.
Chesterton and Mr. George Bernard Shaw. We may be said to know them
well. Leaving out of sight the Celtic strain claimed by one, and indeed
all inherited differences, we see two men of perhaps equal ability,
near of an age, both living in London, both living by their pen, both
in easy circumstances. When one considers for a moment the different
company these two men keep, their different and opposing outlook on
life, their different and opposing forms of diet for their minds and
bodies (I know which of the two diets of those men I would choose and
with which of them I would prefer to be cast on a desert island) one
can only say that the total experience of Mr. Chesterton differs from
that of Mr. Shaw as cheese from chalk, which things, incidentally, are
an allegory in the philosophy of life.
[36] _Op. cit._ p. 6.
[37] p. 5.
The thought here briefly expressed falls well into line with Prof.
Bateson’s statement that the directing cause of the environment is
essential to the theory of Lamarck, and I do not hesitate to add to
it the assertion that _all environment_, in the wide sense of total
experience, _is discontinuous_. There are no such phenomena in total
experience as unit-characters of allied forms, small variations are the
rule. Without doubt a large proportion of the stimuli received by an
organism are as figures written on a slate and at once wiped off. They
are as the snows of yester year. The most they do is to contribute in
their measure to the metabolism of the organism, being too numerous
and minute to affect any structural change. In a higher form of life
none but those which are frequently repeated in the individual and in
succeeding generations can effect any structural response.
Mould and Sieve.
It will be remembered that a single example was given of a short-haired
dog in which its common habit of lying was associated with a certain
pattern of hair. This introduces and illustrates the very wide
conception of a moulding process undergone by an organism. It is one
familiar to biologists and very much so to Professor Thomson in his
various writings. Not less is he an exponent of the metaphorical work
of the sieve of natural selection. I therefore claim nothing new when,
with the temerity of certain persons treading where others are said
to fear to do so, I invent an inclusive term and propose to call the
two fundamental factors of organic evolution _Plasto-diēthēsis_[38]
in which the conceptions of mould and sieve are included and
hyphenated. This word is no more proposed for its elegance than are
_panmixia_, _amphimixis_ and _tetraplasty_, though perhaps it may be
the etymological superior of one or more of these. It is at any rate
inclusive and perhaps sufficiently audacious to assure the inventor of
the title of Dr. Pangloss of controversial memory. But as hard words
break no bones I have taken this risk and it would appear to be a
convenient “conceptual counter” and even Professor Karl Pearson could
not consistently forbid it. It has at any rate the merit of having a
meaning clear to all friends and opponents alike of Lamarckism. It
will be observed that the two words are placed in what I take to be
their natural order as expressive of the Alpha and Omega of the story
of organic evolution. The moulding process is claimed to precede that
of the sieve, as physiology precedes anatomy and function structure,
in that form of biological speculation which is held here to be the
soundest.[39]
[38] From the Greek. {Πλαστος from verb Πλαττειν to mould.
{διηθειν to strain through.
[39] The twin metaphor here chosen for the name of a complex natural
process should be cleared a little of a certain obscurity of meaning.
A mould is familiar to all in domestic and industrial matters, but
there are two sides to the metaphorical conception. A plastic object
may be moulded by the hand of man as in his ruder, but more laborious
days, or it may be pressed into an artificial mould that he has
made by means of his hands and tools. One of these we know in the
rude pottery made by prehistoric man and the vessel of the potter
described by Jeremiah the prophet. We know also those machine-made
moulds, so accurate as to be fitted for the coinage of a nation and
able to puzzle a clever coiner who tries to copy them. We know the
rough hewing of the stone by the sculptor which follows his moulding
of the clay. And in Sacred Writ we read of a double process when the
Hebrews not content with their object of worship took the golden
ear-rings of their women and Aaron “received them at their hand and
fashioned it with a graving tool, after he had made it a _molten
calf_.” But as no conception of a mould in biological matters, which
connotes the rigid accuracy of the coiner’s mould, can represent the
truth, the rougher and freer meaning of the term is here employed.
A similar double meaning is implicit in the metaphor of the sieve,
considered as a human utensil. I believe we owe this idea of a sieve
to Professor Thomson, but am not sure on this point. But I have not
been able to find any definition as to the way in which the sieve of
natural selection is held to act. A sieve is of course for sifting
substances, and the size of the mesh is adapted by us for the purpose
we have in view. We may want a sieve to hold back for us the fit or
good and allow the unfit or bad to pass through, for example wheat
and chaff, or we may employ it to separate sand for our purposes from
fine gravel. The former is of course the most common of the purposes
for which a sieve is used. So here the comparison of personal
selection with the action of a sieve agrees with this aspect of a
sieve, the fit being retained and the unfit allowed to pass through,
thus agreeing with that view of Spencer’s of the survival of the
fittest which is held by most authorities to be more accurate than
Darwin’s Natural Selection.
So the banns between Lamarck and Darwin are published, not for the
first time of asking, and who shall say that there is cause or just
impediment why these two should not be joined together in holy
matrimony?
I conclude this chapter with a passage from the life of Columbus by
Washington Irving which affords a fitting parallel from history in the
higher development and union of two formerly hostile Kingdoms, and the
moral of it is clear and simple. But as a forensic junior I beg to
enter a _caveat_ to the effect that though the name of Columbus occurs
no suggestion is made of the discovery of a New World.
“It has been well observed of Ferdinand and Isabella that they lived
together not like man and wife whose estates are in common, under the
orders of the husband, but like two monarchs strictly allied. They had
separate claims to sovereignty in virtue of their separate Kingdoms,
and held separate councils. Yet they were so happily united by common
views, common interests, and a great deference for each other, that
this double administration never prevented a unity of purpose and
action. All acts of sovereignty were executed in both their names; all
public writings subscribed with both their signatures; their likenesses
were stamped together on the public coin, and the royal seal displayed
the united arms of Castile and Aragon.”