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LOGICAL AND PERSUASIVE STRUCTURES IN
CHARLES DARWIN'S PROSE STYLE
CHARLES KAY SMITH
Abstract
Charles Darwin was a more interesting and dedicated writer than he is commonly credited for
being. This essay will attempt to reassess the importance of his writing. The surface
characteristics of Darwin's prose (conventionally referred to as his "style") seem at first glance
so plain and ordinary that Darwin's writing rarely interests students of style. Exceptions such as
Theodore Baird in an essay entitled "Darwin and the Tangled Bank"1 and Stanley Edgar Hyman
in a longer study of Darwin's writing, The Tangled Bank,2 both make a point of the current
general disregard of Darwin as a writer. But Darwin took considerable pains with the writing,
particularly with his organization, sentence structure and metaphors. In his autobiography he
says: "I have as much difficulty as ever in expressing myself clearly and concisely; and this
difficulty has caused me a very great loss of time; but it has had the compensating advantage of
forcing me to think long and intently about every sentence.... I will add that with my large
books I spend a good deal of time over the general arrangement of the matter."3 And Francis
Darwin in describing his father's characteristic writing behavior tells us: "On the whole, I think
the pains which my father took over the literary part of the work was very remarkable" (I, 131).
My analysis of Darwin’s writing will redefine style as a kind of literary ethogram of an
individual’s writing behavior rigorous enough to allow a professional writer to duplicate from
the analysis, using different subject matter, that same style without necessarily having seen the
original text.
"If we try to discover why Darwin has been overlooked while other Victorian prose
writers have attracted so much attention, we run up against literary tastes and prejudices
dating back to the romantic period. In the first place, Darwin's subject matter is science
and scientific writing is not generally considered Literature. Students of style and
linguistics, though not necessarily guided by the values of students of Literature, have
tended to stay within the literary canon in their choice of subjects, perhaps to ensure their
work an informed audience outside their specialty. But it is not only subject matter that
discriminates against Darwin. Romantic disjunctions between cognitive and emotive,
discursive and non-discursive writing still prevail, and the former is nearly always at a
disadvantage with literary critics; "goal-oriented" in its structure, "referential" in its
language, discursive prose is not considered "imaginative" writing (i.e., not considered
Literature).
The conventional definition of style, which does not recognize organization as one of
its elements, also discriminates against Darwin. Unless we can broaden our definition to
include organization, stylistic analysis of Darwin's prose will not reveal the area of his
greatest skill and subtlety as a writer. It seems clear that to attempt a thorough and
systematic analysis of writing behavior, we must consider all the structures, large and
small, conscious and unconscious, that a writer uses. Thus, instead of assuming that style
is the clothing or ornament of thought, we should recognize that the organization and
presentation of thought can be as individual and as characteristic as any other stylistic
structure a writer habitually uses. Stylistic analysis, if it aims at presenting a complete
and accurate description of an author's writing behavior, must be concerned with the
relation of organizing structures to the more noticeable elements of style like diction and
syntax.
Lack of interest in organization and in discursive writing in general has resulted in a
failure to appreciate Darwin's integration of both logical and persuasive, discursive and
non-discursive modes of writing. There has been only rather general investigation of
Darwin's pattern of logical or discursive organizing in the Origin of Species (Julian
Huxley finds it a "blend of induction and deduction")4 and little notice has been taken of
his non-discursive methods of organizing, nor has there been any detailed study of
precisely how he integrates discursive and non-discursive structures. In the late
nineteenth century when the general theory of evolution was secure but attacks on natural
selection as the mechanism of evolution could still find a publisher, the Duke of Argyll
pointed out some of Darwin's obvious non-discursive techniques to attack his writing as
not properly "scientific,"5 while, ironically, on the other hand, men of letters, recognizing
only Darwin's obvious discursive structures, arrived at the opposite disjunctive
conclusion: that his writing could not be considered "Literature."6
In a letter to Asa Gray, written in 1857, which Darwin allowed to be read publicly at
a meeting of the Linnean Society in 1858, he announced for the first time the hypothesis
on which he had worked patiently for twenty years. This letter eventually became justly
famous, for it is a microcosm "each paragraph occupying one or two chapters in my
book" (I, 478) both conceptually and stylistically of the Origin of Species. (Darwin
seems to have made a practice, while in the process of writing his books, of using
interesting abstracts in letters to his friends.) Because the letter presents essentially the
same techniques of persuasion and steps of logic as the Origin, I believe it can serve as a
manageable sample of Darwin's writing style.
Here is the letter to Asa Gray published by the Linnean Society as it was read the year
before the publication of the Origin of Species:
1. AIt is wonderful what the principle of selection by man, that is the picking out
of individuals with any desired quality, and breeding from them, and again picking
out, can do. Even breeders have been astounded at their own results. They can act
on differences inappreciable to an uneducated eye. Selection has been methodically
followed in Europe for only the last half century; but it was occasionally, and even
in some degree methodically, followed in the most ancient times. There must have
been also a kind of unconscious selection from a remote period, namely in the
preservation of the individual animals (without any thought of their offspring) most
useful to each race of man in his particular circumstances. The "roguing," as
nurserymen call the destroying of varieties which depart from their type, is a kind
of selection. I am convinced that intentional and occasional selection has been the
main agent in the production of our domestic races; but however this may be, its
great power of modification has been indisputably shown in later times. Selection
acts only by the accumulation of slight or greater variations, caused by external
conditions, or by the mere fact that in generation the child is not absolutely similar
to its parent. Man, by this power of accumulating variations, adapts living beings to
his wants may be said to make the wool of one sheep good for carpets, of another
for cloth, &c.
2. ANow suppose there were a being who did not judge by mere external
appearances, hut who could study the whole internal organization, who was never
capricious, and should go on selecting for one object during millions of generations;
who will say what he might not effect? In nature we have some slight variation
occasionally in all parts; and I think it can he shown that changed conditions of
existence is the main cause of the child not exactly resembling its parents; and in
nature geology shows us what changes have taken place, and are taking place. We
have almost unlimited time; no one but a practical geologist can fully appreciate
this. Think of the Glacial period, during the whole of which the same species at least
of shells have existed; there must have been during this period millions on millions
of generations.
3. AI think it can be shown that there is such an unerring power at work in
Natural Selection (the title of my book), which selects exclusively for the good of
each organic being. The elder De Candolle, W. Herbert, and Lyell have written
excellently on the struggle for life; but even they have not written strongly enough.
Reflect that every being (even the elephant) breeds at such a rate, that in a few
years, or at most a few centuries, the surface of the earth would not hold the
progeny of one pair. I have found it hard constantly to bear in mind that the
increase of every single species is checked during some part of its life, or during
some shortly recurrent generation. Only a few of those annually born can live to
propagate their kind. What a trifling difference must often determine which shall
survive, and which perish!
4. ANow take the case of a country undergoing some change. This will tend to
cause some of its inhabitants to vary slightly not but that I believe most beings
vary at all times enough for selection to act on them. Some of its inhabitants will be
exterminated; and the remainder will be exposed to the mutual action of a
different set of inhabitants, which I believe to be far more important to the life of
each being than mere climate. Considering the infinitely various methods which
living beings follow to obtain food by struggling with other organisms, to escape
danger at various times of life, to have their eggs or seeds disseminated, &c. &c, I
cannot doubt that during millions of generations individuals of a species will be
occasionally born with some slight variation, profitable to some part of their
economy. Such individuals will have a better chance of surviving, and of
propagating their new and slightly different structure; and the modification may
be slowly increased by the accumulative action of natural selection to any
profitable extent. The variety thus formed will either coexist with, or, more
commonly, will exterminate its parent form. An organic being, like the
woodpecker or misseltoe, may thus come to be adapted to a score of contingencies
natural selection accumulating those slight variations in all parts of its structure,
which are in any way useful to it during any part of its life.
5. AMultiform difficulties will occur to every one, with respect to this theory.
Many can, I think, be satisfactorily answered. Natura non facit saltum answers
some of the most obvious. The slowness of the change, and only a very few
individuals undergoing change at any one time, answers others. The extreme
imperfection of our geological records answers others.
6. AAnother principle, which may be called the principle of divergence, plays, I
believe, an important part in the origin of species. The same spot will support
more life if occupied by very diverse forms. We see this in the many generic forms
in a square yard of turf, and in the plants or insects on any little uniform islet,
belonging invariably to as many genera and families as species. We can
understand the meaning of this fact amongst the higher animals, whose habits we
understand. We know that it has been experimentally shown that a plot of land
will yield a greater weight if sown with several species and genera of grasses, than
if sown with only two or three species. Now, every organic being, by propagating
so rapidly, may be said to be striving its utmost to increase in numbers. So it will
be with the offspring of any species after it has become diversified into varieties, or
sub-species, or true species. And it follows, I think, from the foregoing facts, that
the varying offspring of each species will try (only few will succeed) to seize on as
many and as diverse places in the economy of nature as possible. Each new variety
or species, when formed, will generally take the place of, and thus exterminate its
less well-fitted parent. This I believe to be the origin of the classification and
affinities of organic beings at all times, for organic beings always seem to branch
and sub-branch like the limbs of a tree from a common trunk, the flourishing and
diverging twigs destroying the less vigorous the dead and lost branches rudely
representing extinct genera and families.
AThis sketch is most imperfect; but in so short a space I cannot make it better.
Your imagination must fill up very wide blanks.@7
Darwin’s writing becomes particularly interesting when we consider his position, in
the letter to Gray, and later in the Origin of Species, was necessarily a defensive one.
Unable to offer any direct proof of his theory, he had to structure an argument which
would be convincing yet which would not antagonize readers whose emotions were
bound up in their intellectual constructs.
This, however, is not an unusual position for a scientific theorist to find himself in,
according to Thomas S. Kuhn in The Structure of Scientific Revolutions.8 Kuhn reveals
that a change in basic theory within a science has usually been a much more traumatic
and extra-logical affair than the conventional textbook picture of completely reasonable
scientists (who immediately recognize and accept the logic of a new theory) would lead
us to suppose. Many philosophers of science today would agree with Kuhn that a
theoretical model of nature, such as the one Darwin offers here, cannot be proved. A
model, or paradigm, they say, depends on a set of assumptions that, like a set of axioms
in mathematics, can either be accepted or rejected but cannot be proved true or false.
There really was no way Darwin could prove his hypothesis concerning the origin
of all organic species short of actually producing a new species in the laboratory under
repeatable conditions, which might have taken (we think now) more than several
million years. But Darwin was too sophisticated a scientist to suppose that such proof
was necessary for the acceptance of his theory. In 1861, he wrote to F. W. Hutton: "I
am actually weary of telling people that I do not pretend to adduce direct evidence of
one species changing into another, but that I believe that this view in the main is
correct, because so many phenomena can be thus grouped together and explained..@9
Darwin here has cited a major reason for accepting a new paradigm and rejecting the
old: the new model explains many previously unexplained facts, and organizes them
coherently. But this is far from being proof; the old model will also explain facts or it
would not have been in use. In speaking of logical arguments for a new scientific
paradigm Kuhn says:
AAll the arguments for a new paradigm discussed so far have been based
upon the competitors' comparative ability to solve problems. But they are
neither individually nor collectively compelling. Fortunately, there is also
another sort of consideration that can lead scientists to reject an old paradigm
in favor of a new one. These are the arguments, rarely made entirely explicit,
that appeal to the individual's sense of the appropriate or the aesthetic.@10
In light of the quotation from Darwin and, more especially the one from Kuhn,
which suggests that non-rational factors enter into scientific change, the importance
Darwin attached to his writing becomes understandable. Darwin was not solving a
long unsolved problem; he was presenting an answer to questions almost nobody else
was asking. His contemporaries already had a model. The Biblical account of
independent creation of species in Genesis seemed satisfying both scientifically and
aesthetically. And to supplant that model, Darwin would have to offer a very
persuasive argument, not simply an orderly proof.
The older model based on the assumption of special creation seemed a lot more
convincing to Darwin's contemporary readers than we may now imagine, and Darwin's
new hypothesis involved a number of unfamiliar assumptions which were likely to
meet resistance. Darwin was asking readers to contemplate something which they
could not concretely experience, an integral calculus11 of almost infinite gradations or
variations in natural history. The concrete experience of each man's few years on earth,
on the other hand, impressed him with the supposed permanence of species, seemingly
proved by the infertility between species or the sterility of rare hybrids such as mules.
And in many cases, Darwin was combating, not mere observation and common sense,
but Scripture. It was necessary to revise his reader's assumptions of a short time span
since the Creation, which was traditionally said to have happened sometime around
4004 B.C., a date endorsed in print in most Bibles of Darwin's day that contained a
table of Scriptural history. Naturalists were not used to thinking of millions of years of
small adaptive changes in organisms. In paragraph 2 of the letter Darwin tries to make
his readers think of time in the same extended terms (natural processes occurring over
millions of years rather than only several thousand) that Lyell and other geologists had
already begun to condition their readers to think in: "We have almost unlimited time;
no one but a practical geologist can fully appreciate this. Think of the Glacial period,
during the whole of which the same species at least of shells have existed; there must
have been during this period millions on millions of generations."
It is obvious that scientists with a lifetime of work and achievement invested in the
old paradigm would be reluctant to accept the new. The history of science is littered
with eminent men who died believing that the new model in their field was a senseless
aberration. But more surprising than the understandable and much publicized resistance
met by Darwin's new theory was its rapid acceptance: "It has often been asserted that the
first reaction to Darwin's theories was uniformly hostile. That is, however, hardly
correct."12
There were several possible causes for the theory's quick acceptance. In the first
place, since the entire first edition of the Origin of Species sold out on the day of
publication, and the second edition soon after it appeared (I, 70), Darwin's letter read
to and published by the Linnean Society prior to the publication of the Origin of
Species may have had some effect even before the Origin appeared in 1859. Darwin
was surprised by the lack of overt response to his letter, and thought that it had failed
partly because it was too brief and partly because it was "badly written" (I, 69). (He
almost always expressed as modest and deprecating an attitude toward his ability as a
writer as he did toward his other obvious abilities.)13 Joseph Hooker reveals more
about the impact of the letter when he reports after it was read (with two other short
pieces on evolution, one by Darwin and one by Alfred Wallace) to the Linnean Society
in 1858: "The interest excited was intense, but the subject-was too novel and too
ominous for the old school to enter the lists, before armouring. After the meeting it
was talked over with bated breath..." (I, 482). Years afterward one of the members,
George Bentham, explains his own reaction to the reading of Darwin's letter:
AOn the day that his celebrated paper was read at the Linnean Society, July
1st, 1858, a long paper of mine had been set down for reading, in which, in
commenting on the British Flora, I had collected a number of observations and
facts illustrating what I then believed to be a fixity in species, however difficult
it might be to assign their limits, and showing a tendency of abnormal forms
produced by cultivation or otherwise, to withdraw within those original limits
when left to themselves. Most fortunately my paper had to give way to Mr.
Darwin's and when once that was read, I felt bound to defer mine for
reconsideration; I began to entertain doubts on the subject, and on the
appearance of the "Origin of Species," I was forced, however reluctantly, to
give up my long-cherished convictions, the results of much labour and study,
and I cancelled all that part of my paper which urged original fixity, and
published only portions of the remainder in another form, chiefly in the
"Natural History Review." (II, 88)
Several other possible causes for the fairly swift acceptance of Darwin's theory
within the scientific community have been offered, by A. O. Lovejoy14 among others.
However, such scientific reasons would not explain the appeal of Darwin's theory to
readers who were non-scientists, and Darwin himself disagreed that his theory of
evolution was ready to be accepted, even among scientists, before the publication of
the Origin, of Species: "It has sometimes been said that the success of the Origin
proved 'that the subject was in the air,' or 'that men's minds were prepared for it.' I do
not think that this is strictly true, for I occasionally sounded not a few naturalists, and
never happened to come across a single one who seemed to doubt about the
permanence of species." (1.71)
Thus the fact that Darwin's new theory caught on quickly within the scientific
community and, surprisingly, even outside it, might in part be attributed to his skill as a
writer who could present a convincing argument and at the same time suggestively
move readers. Indeed Darwin appears to have considered convincing an audience of a
new idea just as important as having made the initial discovery of that idea, for he says
about one aspect of his theory: "... it is clear that I failed to impress my readers; and he
who succeeds in doing so deserves, in my opinion, all the credit" (I, 72). And in a letter
to W. B. Carpenter written in 1859 he says: "Though I, of course, believe in the truth of
my own doctrine, I suspect that no belief is vivid until shared by others" (II, 19).
Though the Origin was not an easy book, and though it aroused the hostility of many
who never read it and even of some who did, it became a best seller and was translated
into many different languages within a few years. Darwin seems to have known (when
he was in good spirits) even before publication that the presentation of his new theory
was well written and would be well received. He wrote to Hooker in April, 1859: "You
will think me presumptuous, but I think my book will be popular to a certain extent...
amongst scientific and semiscientific men; why I think so is, because I have found in
conversation so great and surprising an interest amongst such men, and some Oscientific [nonscientific] men on this subject, and all my chapters are not nearly so dry
and dull as that which you have read on geographical distribution" (I, 509). And in a
letter to Murray, his publisher, he says: "It may be conceit, but I believe the subject will
interest the public..." (I, 511). However, even he was surprised at how popular the
Origin became. He writes for instance in January, I860: "... I never dreamed of my book
being so successful with general readers" (II, 64); and a month later: "... I assure you I
am astonished at the impression my book has made on many minds" (11,67-68).
In the passage from The Structure of Scientific Revolutions quoted earlier, T. S.
Kuhn refers to "the individual's sense of the appropriate or the aesthetic" as a factor in
paradigm shifts. It seems probable, in the light of Kuhn's conclusions, that one of the
reasons for the rapid acceptance of Darwin's theory was its manner of presentation.
Darwin's case is one of the few in the history of science in which the basis of the new
paradigm has been thoughtfully presented in writing for both scientists and
nonscientists alike. (Huxley realized that Darwin's book would convince a wide
audience when he first read it in 1858: "Nothing I think, can be better than the tone of
the book, it impresses those who know nothing about the subject" [II, 26].) Few
scientists before or since Darwin have been accomplished enough as writers to know
when to use logic yet how to avoid dealing in a solely logical mode with the most
emotional areas of possible resistance to change. Few writers have been as capable as
Darwin was in arguing, imaginatively yet convincingly, ideas that arouse emotional
antagonism. Darwin, as we shall see, writes with attention to both aesthetics and logic
when setting out his theory in this letter.
Darwin’s Logical Structures
We might begin an analysis of Darwin's style by examining the first sentence of
each of his first three paragraphs:
1. It is wonderful what the principle of selection by man, that is the picking out of
individuals with any desired quality, and breeding from them, and again picking out,
can do.
2. Now suppose there were a being who did not judge by mere external
appearances, but who could study the whole internal organization, who was never
capricious, and should go on selecting for one object during millions of generations;
who will say what he might not effect?
3. I think it can be shown that there is such an unerring power at work-in Natural
Selection (the title of my book), which selects exclusively for the good of each organic
being.
The first sentence is related to the second by analogy. Considering that humans can
do wonderful things in a few years by selective breeding, how much more effective
might be the work of some superhuman being who was much more thorough and
selected over a much greater span of time? Schematically the analogy goes something
like this:
"It [what the principle of selection by man can do] is wonderful..."
p
is
q
"Now suppose" super selection by a superhuman "being," then "who will say what
he might not effect?"
if
super
P
then
Q
Both the q and Q terms seem purposely kept indefinite while in each sentence a
long clause specifically defines both p and P. In the first sentence the common human
activity of selecting is abstracted into "the principle of selection (by man)," but it is
still defined in fairly concrete terms as
“the picking out of individuals with any desired quality,
and breeding from them,
and again picking out,...”
Notice how deftly Darwin uses the technique of parallelism here not just to dress
up his writing but because he needs a repetitive rhetorical effect to clarify and
emphasize the repetitive process of selection accumulating desirable qualities over a
period of time.
In the first sentence Darwin has talked of the "principle of selection by man." But
in sentence 2 the connection with human selection is dropped and "selection" becomes
an abstract concept rather than a concrete process. "Selection" undergoes further
abstraction as we are asked to suppose a superhuman agency elevated quite out of any
human context. Darwin now defines the principle of selection by superhuman, an
omniscient "being
who did not judge by mere external appearances, but
who could study the whole internal organization,
who was never capricious, and
[who] should go on selecting for one object during millions of generations. . . .”
Notice that as in the definition of "selection" in sentence 1, because he is defining a
“being” with several related attributes engaged again in the repetitive process of
selection, Darwin emphasizes the relation and repetition with parallel grammatical
structures. And the fact that the definitions of both selection by man and selection by
super being are constructed of grammatical parallels makes it easier for the reader to
grasp Darwin's analogy between the two.
Now when we look at sentence 3 we see that the "principle of selection" is even
more abstract, now there is no conscious agent involved. Selection has become a
"power" or force in its own right, an organic process that functions entirely within
nature "for the good of each organic being," rather than the artificial selection carried
out by either man or superbeing to adapt "living beings to his wants." To modify this
very abstract concept of n disembodied "power" of selection Darwin chooses the word
"natural," reinforcing the implication that the concrete act of man selecting for his own
uses is in reality a most artificial instance of the operation of the now thoroughly
abstract principle of selection
Let us examine the structure of what seems to be progressive abstracting more
carefully. The initial increments of Darwin's abstracting .are accomplished with the aid
of personification. Darwin uses a subtle personification of an abstract entity in
sentence 1 when he suggests that the principle of selection "can do." He is much more
overt in sentence 2 when he changes the "principle" that "can do" into "a being who" is
even given masculine gender in the phrase "what he might not effect."
We can see in the first paragraph Darwin's careful preparation for his final
increment of abstraction that will divorce "natural selection" from any agent who
consciously picks out. As we have seen in the first sentence Darwin has defined one
kind of selection that operates "by man" consciously "picking out" certain varieties
over and over again. But several sentences later in the first paragraph he defines a
second way in which selection can operate that does not require any conscious help
from man; man is simply part of the process: "There must have been also a kind of
unconscious selection from a remote period, namely in the preservation of the
individual animals (without any thought of their offspring) most useful to each race of
man in his particular circumstances." The activity of the personified "principle of
selection" is made dominant over the activity of man as selector, since man acts in this
case merely as an unconscious bit player in the drama of selection, by unwittingly
giving certain varieties a selective advantage in producing more offspring. All this
happens unconsciously because man simply tends to take better care of an animal he
finds more useful than the others, without any realization that he is breeding for the
future by helping an animal survive longer to propagate more animals like itself.
Another type of more or less unconscious agency through which selection can work its
"astounding" effects by producing more and more distinctive domestic breeds is
exemplified in the habit of roguing: "... 'roguing,' as nurserymen call the destroying of
varieties which depart from their type, is a kind of selection." In each of these cases
Darwin is personifying the power of selection and making man merely the
unconscious instrument of that power. It will not be so hard, after preparing his reader
so carefully, to begin to argue that the power of selection might not need any
conscious agent at all, either human or superhuman, to carry out its important process.
Darwin has incrementally prepared us to accept the possibility of an abstract force
(like Newton's force of gravity) acting by itself, i.e., natural selection. Perhaps he has
done this because the reader is more likely to tentatively accept the new abstraction if
Darwin can ease him progressively away from concrete common sense experience
toward a concept that can finally only be understood intellectually.
In addition to incremental abstracting as a general organizing principle relating the
three initial sentences of the first three paragraphs, we saw earlier that Darwin also
uses analogy to get from sentence 1 to sentence 2. But we have not yet examined
sentence 2 and sentence 3 for any further structural relation. Notice that in its simplest
form sentence 2 makes a hypothetical assertion. A condition p is related to a
consequence q in such a way that if P were affirmed then Q must be the inevitable
result:
who will say what he might not effect?"
if
P
then
Q
And notice that when we now turn to sentence 3 we see that it is, in simplest form,
an affirmation of the conditional term of the hypothetical assertion of sentence 2:
“. . . .there is such an unerring power at work in Natural Selection. . . ."
P is affirmed
Related as these two assertions are, they now imply a conclusion affirming some
effect on nature as a consequence. To relate two assertions in order to imply a third
assertion (or conclusion) is to use a syllogism to organize sentences. The first (or
major) premise is a hypothetical assertion:
condition/consequence
if P
then Q
The second (or minor) premise affirms that the condition is fulfilled. These two
assertions relate in such a way that a third assertion (or conclusion) is made inevitable
and the syllogism is complete.
Now we can see that the first sentences of the second and third paragraphs of
Darwin's letter are the major and minor premises of a syllogism such that if these two
assertions can be proved or accepted as convincing, their relation necessarily implies a
conclusion affirming the consequent term of the hypothetical assertion (i.e., of the
major premise). But let us first take a closer look at this consequence that may be
affirmed in a conclusion. In its present form it seems so vague that it is hard to see
what possible reason Darwin would have to set up major and minor premises simply to
be able to draw a conclusion affirming so enigmatical a consequence. He not only
expresses this consequent term as a rhetorical question, but he purposely employs
figure of speech, litotes, to express the question indirectly, in negative terms: "who
will say what he might not effect?" Yet perhaps affirming this will be like granting
himself a blank check that he can fill out later in a surprising way. At this point in the
letter Darwin may not want to reveal the ultimate conclusion of his argument lest it
generate too much irrational feeling against him from the very beginning. It is not till
the last paragraph that he proposes as his conclusion the bold and highly controversial
hypothesis that natural selection together with the principle of diversity are the two
forces at work in nature that have determined the origin of species for all organic
beings for all time. Perhaps he wants to keep what his reader is soon going to be
forced to conclude under rhetorical wraps until the reader has calmly examined the full
chain of reasoning. Darwin seems to be using rhetoric to introduce an indefinite term
into a syllogistic organization for the purpose of assuring himself a rational audience
who will not be thinking against him from the very first assertion. Thus, Darwin
makes this syllogism function as a rhetorical or persuasive structure as well as a
logical structure. It is true that a syllogistic structure is often associated with a criterion
of proof or validation, but it is best not to confuse a structure with its conventional
purpose, lest we forget that a familiar structure can be used by a writer in a novel way.
We don't find any conclusion affirming the consequence and completing the
syllogism in the third or fourth or fifth paragraphs, and yet some pattern of sequential
reasoning is evident. In the third and fourth paragraphs Darwin is proving his minor
premise ("I think it can be shown that there is such an unerring power at work in
Natural Selection ...") with a chain of syllogisms or informal syllogisms, with one of
the premises unstated but implicit, called enthymemes15. In paragraph 5 Darwin pauses
in his argument, after he has confirmed the existence of natural selection, to answer
possible objections to his conclusions so far. Then in paragraph 6 he explores a new
vein of argument by combining the "principle of divergence" with the "principle of
[natural] selection" that he has just demonstrated. (Darwin often argues informally
with fragments of syllogisms (enthymemes). In such cases, I have added and italicized
premises that are implicit but unstated.)
Paragraph 6. Major: if p, then q
If the same spot or environment will support more life if occupied by very diverse
forms, then the profitable extent to which the power of natural selection will tend to
accumulate modifications will be great enough to allow them to diversify as much as
possible into variations, sub-species, true species.
Minor: p affirmed
"The same spot will support more life if occupied by very diverse forms." Darwin
affirms this assertion with inductive examples and also cites some experimental
evidence.
Conclusion: therefore q
"And it follows, I think, from the foregoing facts, that the varying offspring of
each species will try (only few will succeed) to seize on as many and as diverse places
in the economy of nature as possible."
And if he now adds one more assumption (i.e., “Each new variety or species, when
formed, will generally take the place of, and thus exterminate its less well-fitted
parent."), Darwin can fill in the blank check he gave himself in the consequent term of
the major premise of his general argument in paragraph 2 and conclude the macrosyllogism that structures his whole argument with a bold statement of his general
theory of evolution:
"This I believe to be the origin of the classification and affinities of organic beings
at all times, , , ,”
Analysis of the Macro-Syllogism that Organizes Darwin's Argument
Paragraph 2. Major: if p, then q
"Now suppose there were a being who did not judge by mere external appearances, but
who could study the whole internal organization, who -was never capricious, and should
go on selecting for one object during millions of generations; who will say what he might
not effect?" This assertion, that a super-selective power would accomplish a super-effect,
is arrived at by analogy with paragraph 1, which explains the impressive effect in only a
short time of man's selective power in breeding.
Paragraph 3. Minor: p affirmed
"... there is such an unerring power at work in Natural Selection...."
Paragraphs 3, 4, 5.
The minor premise is affirmed with an argument (see footnote 15) composed of a
chain of logic, whose assertions are characteristically backed up by one or two carefully
chosen inductive examples.
Paragraph 6. Conclusion: therefore q
The indefinite super-effect consequence of the major assertion in paragraph 2 is
now affirmed in the definite form of the origin of species, i.e., "the origin ... of organic
beings at all times." The principle of diversity (affirmed by inductive examples) has
been combined with the principle of selection to explain the ultimate consequences of
the power of natural selection. This concludes the macro-syllogism and completes
Darwin's argument.
It is not only in the letter to Asa Gray that we meet a chain of logical argument
from beginning to end; essentially the same syllogistic structuring is used in the Origin
of Species, where Darwin says in the concluding chapter: ". . . .this whole volume is
one long argument. . . ."16 In 1859 Darwin discusses the logical organization of the
Origin in a letter to Lyell: ". . . .I am convinced there is not a sentence which has not a
bearing on the whole argument." (I, 519)
Darwin apparently learned to relate sentences and paragraphs (or even chapters) to
one another in these long chains of logic from his very careful study of William
Paley's Evidences of Christianity and Natural Theology, of which Darwin once wrote:
"I do not think I hardly ever admired a book more than Paley's 'Natural Theology'" (II,
15). Paley's long arguments to confirm the teleologic plan of the natural universe are
organized by intricate chains of deductive and inductive logic, which Darwin found so
convincing, as well as aesthetically pleasing, that he tells us he actually had committed
the Evidences to memory:
In order to pass the B.A. examination, it was also necessary to get up
Paley's "Evidences of Christianity," and his "Moral Philosophy." This was
done in a thorough manner, and I am convinced that I could have written out
the whole of the "Evidences" with perfect correctness, but not of course in the
clear language of Paley. The logic of this book and, as I may add, of his
"Natural Theology," gave me as much delight as did Euclid. The careful study
of these works, without attempting to learn any part by rote, was the only part
of the academical course which, as I then felt and as I still believe, was of the
least use to me in the education of my mind. I did not at that time trouble
myself about Paley's premises; and taking these on trust, I was charmed and
convinced by the long line of argumentation. (I, 40 1)
(Obviously Darwin is operating under a different aesthetic than current literary
aestheticians who can be convinced by but cannot at the same time feel charmed and
delighted by discursive writing, since ironically the disjunctive structure of their own
assumptions will allow them to consider only non-discursive writing a valid object of
aesthetic feelings.)
To return to our analysis of the letter, we have seen that many of Darwin's sentences
are assertions organized into logical patterns. These assertion sentences share a common
structure; they relate one noun phrase or clause to another, using some informal but
recognizable variant of conventional logical syntax, such as "if p, then q" (hypothetical )
or "all x is y" (categorical), etc. To compose his assertion sentences Darwin often
transforms whole sentences into various kinds of nominals which then are able to
occupy positions as subject complements and other nominal elements in the main
sentences. And by prefixing "that" to one of the constituent sentences Darwin can
occasionally fit a long noun clause into any grammatical position that a noun phrase
may occupy. Often a noun phrase that serves as a term of the assertion is defined by a
clause that interrupts the sentence, so that the definition is thereby placed as close as
possible to the term being defined. Notice that the first sentence of each of the first three
paragraphs (see p. 252) fits the description above. Sentence 1 is an x is y assertion with
the x term defined in a clause in apposition that interrupts the sentence. Sentence 2 is an
if p, then q assertion but also manages to define the p term with long clauses. And
sentence 3 makes an x is y assertion, this time defining the y term, "natural selection," in
a clause. The high density of these assertion sentences interrupted by definitions of
terms, with each assertion logically related to others, achieves a compression of
argument which was certainly one of Darwin's goals in writing this letter. A wish to
write compactly is also evident in Darwin's omission of assertions that he feels the
reader can supply for himself.
Darwin characteristically makes his assertions seem informal rather than rigorous.
Sometimes he reverses conventional logical syntax, for instance casting a hypothetical
assertion backwards in the following sentence: "The same spot will support more life
if occupied by very diverse forms." Or, as in the first sentence of the second
paragraph, he makes an unconventional if p, then q assertion in a sentence stated as a
rhetorical question. He expresses the conditional if term as "now suppose there were a
being," and slides into the consequent term on the end of a series of parallels: "who
...," "who...," "who...," "[then] who will say what he might not effect?" We already
noticed that he seems to express the consequent term in the purposely indirect syntax
of litotes. Almost never does Darwin allow his expression of assertions in logical
patterns to sound coldly and uncompromisingly formal.17
Darwin's relatively informal but essentially logical sentence structuring suggests,
as did his incremental abstracting, that though one of his aims is to write a convincing
argument, another must be to persuade informally. He is evidently too tactfully
humane and also probably too practical a psychologist to think he can win over a
reader on a sensitive theoretical subject by pushing him into a logical one-way street
with the sign "Q.E.D." at the end. Asa Gray's first reaction to the Origin suggests that
Darwin was wise in not relying entirely on rigorous logic to change people's minds.
After reading the argument of the whole Origin of Species (of which the letter
published by the Linnean Society was an abstract), Gray wrote: "The moment I
understood your premisses [sic], I felt sure you had a real foundation to hold on. Well,
if one admits your premisses, I do not see how he is to stop short of your conclusions,
as a probable hypothesis at least" (II, 66). And yet in this same letter Gray confesses
himself, in spite of the logical argument, as nevertheless "standing non-committed as
to its full conclusions." Thus, though the logic did not convince Gray on first reading,
Darwin's tactful and persuasive style did not antagonize him; and it apparently allowed
him to consider the argument on subsequent readings and on reflection, so that he was
eventually able to accept the conclusions which initially went against his own
scientific and religious beliefs.
Even considering the density of logically related assertions that is characteristic of
his style, much of Darwin's writing in the letter is not part of his chain of syllogisms or
enthymemes. For example, Darwin does not often allow an abstract assertion to stand
far from a concrete restatement or example. Sometimes even in the same sentence he
suggests the concrete example (such as elephants multiplying rapidly) most likely to
strike our imaginations. We are quickly made aware how a species breeding without
restriction might in a short time populate the whole earth: "Reflect that every being
(even the elephant) breeds at such a rate, that in a few years, or at most a few
centuries, the surface of the earth would not hold the progeny of one pair." And after
Darwin has made the abstract statement: "Such individuals will have a better chance of
surviving, and of propagating their new and slightly different structure; and the
modification may be slowly increased by the accumulative action of natural selection
to any profitable extent," he follows with this concrete restatement: "An organic being,
like the woodpecker or misseltoe, may thus come to be adapted to a score of
contingencies."
Often Darwin's examples not only make the writing more concrete but also serve his
goal of compression by suggesting in shorthand the possibility of a complete inductive
proof to back up the assertions they follow, as in this instance: "The same spot will
support more life if occupied by very diverse forms," followed by: "We see this in the
many generic forms in a square yard of turf." Darwin then becomes more concrete and
briefly indicates a possible inductive experimental proof with grass seeds: "We know
that it has been experimentally shown that a plot of land will yield a greater weight if
sown with several species and genera of grasses, than if sown with only two or three
species."
Almost every other sentence contains a concrete example, or repetition in
somewhat more concrete terms, of an assertion he has just introduced. Darwin's last
concrete example comes at the end of his letter where he exemplifies his whole
argument with the simile of the Tree of Life. It is obvious that the Tree of Life
example is not part of the logic but that he is appealing directly to his reader's
imagination by offering him a simile to summarize concretely and persuasively all he
has been saying: "for organic beings always seem to branch and sub-branch like the
limbs of a tree from a common trunk, the flourishing and diverging twigs destroying
the less vigorous--the dead and lost branches rudely representing extinct genera and
families." Now let us begin to investigate in more detail such extralogical means of
persuasion in Darwin's style.
Darwin’s Persuasive Structures
As I mentioned earlier, it is a popular practice today to make a dichotomy of logic
and persuasion or, as it is sometimes phrased, discursive and non-discursive writing.
Far from behaving according to such a dichotomy, however, Darwin seems willing to
integrate the two functions of thinking logically and thinking persuasively.
We have already seen Darwin use logical structures in his writing, but so far we
have focused on only a few of his imaginative structures. If we can assume that
Darwin intended more than simply a logical argument and that he was also interested
in persuading his reader, we can begin to see how many stylistic traits that we have not
yet considered fit into the total pattern of his writing.
Darwin occasionally uses an affective vocabulary (even in a premise). For
instance, in characterizing the effects of the principle of selection as "wonderful" and
as something that professionals are "astounded" by, or at another time calling it a
"great power," Darwin expresses or perhaps seeks to stimulate almost aesthetic
feelings for this key abstraction. And notice the attitude of awed respect in the
expression of the consequences of selection in the rhetorical question "who will say
what he might not effect?" This aesthetic attitude of awe and respect toward his
subject, the processes of nature, is so noticeable in Darwin's style that his sons teased
him about the affective words he used. They decided, for example, that the following
phrases sounded more like commercial advertising copy than science writing: "a larval
cirripede, 'with six pairs of beautifully constructed natatory legs, a pair of magnificent
compound eyes, and extremely complex antennae'" (I, 131).
Personification was, as we saw, one of Darwin's techniques of incremental abstracting
and is a pervasive figure of speecli in this letter. Not only does Darwin personify the
"principle of selection," but he also personifies the "principle of divergence," saying that
it "plays an important part." The area of human behavior that Darwin links to this force of
nature is dramatic acting. The verb "to act" is used more than once to personify the
functioning of natural selection. Darwin's account of the origin of species is millions of
years slower than the Biblical drama of creation in the Book of Genesis, but by a few
subtle personifications of natural forces that "act" or "play a part," he suggests that
natural evolution too is dramatic.18 Darwin populates nature with what he calls "organic
beings." Since "organic being" is a broader term than animal, vegetable, or human being,
by using the term Darwin implicitly casts man together with animal and vegetable
"beings" in the drama of evolution. To all these "beings," including vegetables, Darwin
seems to grant--in the way he talks about their engagement in a "struggle for life"--an
anthropomorphic consciousness of their predicament. And what we might describe today
as primitive sex drive Darwin elevates into a conscious responsibility for large-family
planning, for each being is said to be "striving its utmost to increase in numbers." Darwin
often personifies animals by referring to them in the human terms of "parent" and "child,"
again subtly undermining the traditional assumption of the fundamental difference
between man and animal and suggesting instead that humans and animals are inherently
related. By personifying animals and vegetables Darwin establishes a metaphorical link
between nature and man, while, on the logical level, he is convincing us through
argument that each "organic being" is organically related to all other beings in nature. In
other words here again Darwin is using both the techniques of imaginative persuading
and logical convincing in order to extrapolate his new theoretical model without a direct
confrontation of his reader on a sensitive issue that might provoke irrational hostility.
In a letter, written in 1857, to Wallace, who had asked Darwin if he intended to
broach the subject of the evolution of man in setting out his theory, Darwin answers:
"You ask whether I shall discuss 'man.' I think I shall avoid the whole subject, as so
surrounded with prejudices; though I fully admit that it is the highest and most
interesting problem for the naturalist" (I, 467). Darwin's letter to Cray, though it never
states it, reveals an organic relation between man and the rest of nature that poets like
Wordsworth had been suggesting metaphorically since the beginning of the romantic
movement. Perhaps one of the things that made Darwin's writing so surprisingly
popular with both scientists and laymen is that he had ventured to the heart of the
popular nineteenth-century romantic mystery of man's organic relation to all of nature,
and had not only written of it suggestively in metaphors but had explained his organic
vision theoretically, in a scientific sense, without mystery. As a writer Darwin seems
in this letter both poet and scientist. We find him persuading as well as convincing his
reader to accept a new vision of the world that fundamentally changed the relation of
man to nature and nature to God.
This relation of nature to God is another very delicate subject that Darwin chooses
to deal with metaphorically and suggestively, as he dealt with the relation of man to
nature. We saw earlier that in the first sentence of the second paragraph Darwin speaks
of the "principle of selection" in terms usually reserved for God, a superhuman
masculine "being" who makes the same kind of selections that a man might make, but
more omnisciently: "who could study the whole internal organization"; and more
infallibly, "who was never capricious"; over an eternity of time, "and should go on
selecting for one object during millions of generations"; and who shares another
attribute of divinity since he is apparently omnipotent and can accomplish almost
anything. Now Darwin knew that Gray, his immediate reader, to whom the letter was
addressed, was a religious man as well as a first-rate scientist. He seems to be
purposely using an ambiguous analogy and suggestive personification in the second
paragraph, tactfully designed to allow Gray and others who might read his abstract to
retain their belief in God (who may be imagined working behind the physical screen of
natural processes), and still accept the materialistic explanation of the physical
operation of "natural selection," which he introduces in the next paragraph. Darwin is
advancing an argument in n very sensitive area and is using a rhetoric of restraint and
tact in order to convince Gray of nature's material processes, yet not outrage any of
Gray's extra-scientific beliefs or sensibilities. Darwin's writings effected an intellectual
revolution, and today we often assume that it is a characteristic of revolutionary
thinkers to provoke confrontations. However the avoidance of any unnecessary
polarizing confrontation was characteristic of Darwin's style as he tells us in his
autobiography: "I rejoice that I have avoided controversies, and this I owe to Lyell,
who many years ago, in reference to my geological works, strongly advised me never
to get entangled in a controversy, as it rarely did any good and caused a miserable loss
of time and temper" (I, 72).
Darwin's rhetorical ambiguities, calculated to avoid a polarizing confrontation on a
highly charged religious issue that was actually irrelevant to his scientific argument,
seem to have worked well enough, for Gray became Darwin's chief American disciple,
defending Darwin against all charges that his views were necessarily irreligious. In
Darwiniana, Gray's collection of essays in defense of Darwin, published in 1876, Gray
describes himself in the preface as "one who is scientifically, and in his own fashion, a
Darwinian, philosophically a convinced theist, and religiously an acceptor of the 'creed
commonly called the Nicene,' as the exponent of the Christian faith."19 Indeed, Gray
decided that Darwin's evolutionary theory had brought teleology back to the natural
sciences.20 Gray must have been so disarmed by Darwin's tact that he even advised
Darwin "to assume, in the philosophy of his hypothesis, that variation has been led
along certain beneficial lines,"21 i.e., that God was the ultimate beneficent designer
behind the apparent material causes of evolution. But Darwin did not believe in
supernatural design in nature, and though he was willing to use ambiguity as a technique
to avoid irrelevant controversy, he was not willing to compromise his scientific
convictions. He helped Gray publish his review of the Origin in England, and even
suggested the motto for one of Gray's pamphlets: "Natural Selection not inconsistent
with Natural Theology."22 But after seriously considering Gray's proposal he wrote to
him: ". . . .I grieve to say that I cannot honestly go as far as you do about Design" (II,
146).
Perhaps another reason that Gray and other devoutly religious men became
satisfied with the new theory was its aesthetic appeal. Darwin does not tactlessly
replace the traditional model of creation (that has, over the centuries, built up
accretions of aesthetic feeling and spiritual meaning for his audience) with a cold,
imaginatively unstimulating model. On the contrary, he seems to go out of his way to
suggest to his reader's imagination the richest organic complexity evolving slowly but
dramatically as a result of elegantly simple natural forces.
The letter ends with the extended simile of a great tree that represents the history
of all organic life. (This same extended simile is called the "Tree of Life" in the
summary to Chapter IV of the Origin.)23 The tree, revealing in its gnarled organic
growth the mortal but still green history of nature, has a subtle spiritual suggestiveness
of which it is unlikely that Darwin's contemporary readers, steeped in the Bible, could
have been unaware. As tradition has it, in the Garden of Eden stood a Tree of Life as
well as the Tree of Knowledge from which Adam and Eve ate the forbidden fruit. It
was so they could not also eat of the Tree of Life and attain immortality that God,
according to Genesis, quickly banished man into the world to undergo the brutal cycle
of birth, struggle, and death. Darwin is not simply suggesting the traditional symbol
from Genesis but recreating it by radically changing its meaning to fit his new theory
about the genesis of organic beings. What Darwin seems to suggest is that through
knowledge of biology man may at last have another chance to know the Tree of Life.
Is there even perhaps the suggestion that through such rediscovery man might
experience at least the intellectual satisfaction of knowing that as an ever-evolving
organic being he shares immortality with all Nature? Here as elsewhere in his writing,
Darwin seems to have felt himself under some pressure to relate his new theory to the
traditional Biblical myths in as tactful a way as possible. For example, in the last
sentence of the Origin he says: "There is grandeur in this view of life, with its several
powers, having been originally breathed into a few forms or into one... ,"24 And on at
least one occasion, he expressed regret that he had felt this pressure so greatly: "I have
long regretted that I truckled to public opinion, and used the Pentateuchal term of
creation, by which I really meant 'appeared' by some wholly unknown process" (II,
202-203).
Being ambiguous about whether or not nature is the mask of God is not the only
instance of Darwin's use of rhetorical techniques to achieve tact while vigorously
pursuing a controversial argument. His attitude is modestly tactful, not only toward his
reader and toward earlier writers on the same subject (notice that Darwin corrects them
by seeming to compliment them: "... [they] have written excellently on the struggle for
life; but even they have not written strongly enough.") but also toward his subject
matter. Though Darwin had worked painstakingly for eighteen years on the hypothesis
he advances here for the first time, his style is characterized by interruptions of the
grammatical flow of his argument by qualifications and phrases such as, "I believe" or
"I think it can be shown" (rather than the more modern but less personal and much less
modest "it will be shown").25 He allows that "multiform difficulties will occur to every
one, with respect to this theory," and is even unsure that he can answer all of them:
"Many can, I think, be satisfactorily answered." He says in summing up an argument
whose cogency was to change several thousand years of accumulated tradition, "And it
follows, / think, from the foregoing facts. . . ." At the end he states: "This sketch is most
imperfect; but in so short a space I cannot make it better."
Darwin's verb phrases, such as "may be said to be striving," "there must have been"
contain the kind of auxiliaries that carefully qualify the meaning of the verb so that he
usually manages to keep from sounding categorical or absolutely sure. His frequent use
of auxiliaries like "might," "must," "can," "should," "would," "may," restricts his
assertions, as though he is aware at all times of possible contingencies. Another
auxiliary he often uses (Ahave@ followed by the past participle form) qualifies his verb
in such a way that it suggests rather than states that some action of nature or
evolutionary process is still operating at present even though Darwin can only show the
process having happened in the past, because it acts so slowly. He writes, for example:
"changes have taken place"; "it has become diversified."
In addition to verb qualifiers Darwin uses many quantifiers such as "few," "many,"
"some," "often," "most," that restrict the universality and absoluteness of his
assertions. He uses, sparingly, universal quantifiers like "all" and "none" that might
make him sound too categorical. And he uses adverbs like "occasionally" and
"generally," as well as a number of fixed phrases such as "not absolutely similar," "not
exactly resembling," "seems to be," "in some degree," that qualify his assertions and
prevent him from possibly overstating his case. Of course in the case of Darwin's style
what we are seeing is more than a verbal appearance of modesty and understatement;
it is rather the verbal evidence of a mental habit of open-mindedness and honesty.
In a letter to Asa Gray, in 1859, Darwin had said that he intended the presentation
of the theory of evolution to interest primarily the general scientific reader who, he
hoped, might be a less biased audience than naturalists whose habitual operating
assumptions were opposed to his: "... I think it of importance that my notions should
be read by intelligent men, accustomed to scientific argument, though not naturalists.
It may seem absurd, but I think such men will drag after them those naturalists who
have too firmly fixed in their heads that a species is an entity" (II, 39). Darwin's use of
carefully chosen concrete examples makes his argument more clear and persuasive to
layman and expert alike. Even a child could understand his examples in the letter, such
as seashells, elephants, woodpecker, mistletoe, grass, and tree. Yet, some of these
seemingly simple examples are chosen with extreme care to convey to the professional
or expert far more than the layman who understands the example on a simpler level
might think possible. Some of these suggest a more complete inductive proof. For
instance, when Darwin mentions "the plants or insects on any little uniform islet" as an
example of diverse forms occupying the same spot, his point is understandable to
layman, but he is also referring the expert to, among other references, his own earlier
work, The Voyage of the Beagle, in which he explained in detail the diverse plants and
insects to be found on each of the Galapagos Islands in the Pacific off the coast of
South America.28
And there was excitement for experts in the seemingly simple woodpecker and
mistletoe that Darwin gives as examples of animal and vegetable "organic beings"
which the force of natural selection has in time adapted to their present forms. We may
know that woodpeckers and mistletoe are specifically adapted, but probably unless we
are experts, we will not realize that they are so highly specialized that they had been
stumbling blocks to earlier theories of evolution: "The facts which kept me longest
scientifically orthodox are those of adaptation . . . . the mistletoe, with its pollen
carried by insects, and seed by birds the woodpecker, with its feet and tail, beak and
tongue, to climb the tree and secure insects" (I, 478). The woodpecker is so
specifically adapted to securing insects from trees that it had always seemed before
Darwin's explanation almost necessarily created specially to fulfill a certain purpose.
And the mistletoe had been almost impossible to explain by the best earlier theories of
evolution, particularly Lamarck's theory that based evolution on small changes in
organisms as a result of their willing or striving to change. Even if the mistletoe could
be conceived as capable of willing any change in itself, how could it possibly have
willed the role that insects and birds play in its complicated adaptation to the
environment? The point Darwin is making with these examples is that by his theory of
natural selection it seems possible to explain even these classically difficult cases of
adaptation.
It is odd how we get an impression from reading only this short letter that the person
who wrote it must have both wide and deep knowledge of his subject. Perhaps it is
partly because Darwin's references come from many diverse fields of knowledge
zoology, geology, entomology, ornithology, botany - though, as we have seen they are
chosen with the accuracy of the expert in each field. But this impression certainly does
not come from any ostentatious use of difficult and overly technical words and phrases.
Darwin's vocabulary is quite non-technical for science writing. For instance, in this
letter what he calls simply the "origin" of species, or species being "formed," was
conventionally called by most biologists "transmutation" of species, and even Darwin
occasionally uses the more technical term in his professional correspondence and
notebooks.27 Darwin consistently uses a plain and familiar vocabulary, carefully
defined to express specific technical ideas that until then had not been at all familiar.
He repeats a few common verbs to relate the apparently infinite separate movements
of natural phenomena: "select," "vary," "modify," "adapt," "diverge," "form,"
"struggle," "strive," "change." And the carefully defined theoretical terms with which
he constructs his vast model of nature's regulated processes throughout time are
characteristically nouns formed by adding a "tion" suffix to the simple verb stems.
Because we are all familiar with the verb stems, highly abstract theoretical concepts
signified by the simple words "selection," "variation," "modification," and
"adaptation" seem to represent simple and common acts of nature that almost any
reader can grasp, on whatever more or less precise or profound level he is capable of
understanding.
Another way in which Darwin assures clear communication to a wide audience is
to make the order of presentation of the parts of his theory accord with the steps in his
own discovery of them. In 1837 he started a notebook on breeding domestic animals
(I, 68), and soon became convinced that selection had been the powerful cause that
produced all the impressively different domestic varieties (this first step in his own
research is presented in paragraph 1). He could not until later see how selection could
produce varieties in the wild world of nature, since there was apparently no conscious
agent in the wilderness to do the selecting. But he did realize that if some sort of
selection could be shown to have been working in nature for millions on millions of
generations, it could account for very profound changes indeed (paragraph 2). Then in
1838 he read Thomas Malthus's Essay On Population. While human population
increased geometrically the food supply could at best only increase arithmetically, so
that the more children who survived to mature and reproduce, the more would sooner
or later have to starve to death until the population was brought back into equilibrium
with the food supply. Though Malthus was talking about human population, Darwin
was struck with how well this thesis fit animal populations in a limited environment (I,
68). The combination of Malthus's ideas with his own gave Darwin a vision of all
organic beings engaged in a "struggle for life," for the environment is always too
limited to support the rate of propagation, if more than a small per cent of beings in
each generation survive to reproduce. Darwin's next step is to combine with the idea of
the "struggle for life" the simple observable fact that within the same species (and even
within the same litter) some variations of color, size, structure, etc., normally occur. It
is clear then that a few beings, because of some favorable variation, may have a slight
advantage in the struggle and may live longer to pass on their helpful adaptation to
more progeny than the ones whose variations were not useful. And this explains how
selection could occur in nature without the help of any conscious agent like man to do
the selecting.
However, Darwin had only explained "natural selection"; he could not explain the
origin of all species until much later in his research he began to realize the key
importance of the fact than an environment will tend to support more beings of very
diverse species than of the same or similar species (I, 68-69). (Darwin introduces this
observable fact as the "principle of divergence") If an island will support a certain
number of animals all of whom eat grass, for example, then it would support a larger
number if some of the original animals could adapt to eating leaves and others adapt to
eating their neighbors who are busy fattening themselves on the available grass. In
other words, natural selection would tend to favor the growth of many diverse kinds to
fill up the available niches of survival in the environment. By combining the "principle
of (natural) selection" with the "principle of divergence" Darwin explains a tendency
of nature to select for diversity in any given environment that over a vast period of
time could explain the origin, as he finally points out, of all the various species of
organic beings throughout history. A pattern of discovery that occurred to Darwin over
a period of years he here compresses into a principle of organization to structure six
paragraphs.
It seems very sensible for a writer who is trying to present an innovative and
complex idea to take his reader through a repetition of essentially the way the idea
developed in his own mind. The rhetorical principle would seem to be that if one
person originally achieved discovery through a certain sequence of ideas, then maybe
other human minds presented with an even clearer version of the same sequence of
steps, with all missteps and irrelevancies removed, will find this an easy way to arrive
at the same discovery. Because Darwin has made his logical argument mesh with his
sequence of discovery, a reader can understand Darwin's revolutionary new theory
rather easily in a few paragraphs.
Those who do not recognize Darwin's genius as a writer are usually those who
have not studied his style carefully or perhaps feel that good writing is simply a matter
of appropriate diction. But, as we have seen, the pattern of a writer's grammatical and
organizational structuring can be as important in determining his style as any of his
more obvious rhetorical characteristics.
Charles Darwin was a first-rate scientist who was also a considerable writer. He
put together a style that accomplished many goals; it was designed to convince and
persuade the widest possible audience of the most profound innovation in the most
compact form with the very least pain of discovery. Even though he is working in an
extremely sensitive and controversial area, he is so tactfully aware of possible points
of view different from his own as to disarm even his opponents and allow as many
readers as possible to consider calmly the reasonable argument he is advancing.28
It is obvious from an analysis of Darwin's style that, whether he was conscious of
it or not, his aesthetic assumptions were broad and generous when he wrote this letter.
He could write a logical argument both convincingly and persuasively; he could find
and evoke wonder not only in concrete objects like mistletoe, elephants, and grass, but
in the abstractions of the human mind hypothesizing about the processes of organic
change over millions of years of time.
But Darwin tells us that he gradually lost his "aesthetic" sense (I, 87), "lost... all
pleasure from poetry of any kind, including Shakespeare" (I, 30), and indulged from
then on only in scientific theorizing. Late in life he says: "Looking backwards, I can
now perceive how my love for science gradually preponderated over every other taste"
(I, 53). Apparently Darwin defines "aesthetic" in the common way, excluding the
possibility of aesthetic feeling about mathematics or logic or scientific theory and
seeing only poetry, art, and music as appropriate objects of aesthetic appreciation. In
his scientific literature Darwin's aesthetic criteria remained as in the letter to Asa Gray
wide and integrated enough to make the usual talk of a split between "two cultures"
quite meaningless. But when he lost his aesthetic sense, though it did not seem to
make a difference in his writing, the range of his private aesthetic appreciation became
diminished to half its original compass, and he felt he could experience satisfaction
only in theoretical science. The range of his diminished aesthetic sensibility was then
equal but opposite to the range of aesthetic sensibility of many literary aestheticians
who can feel sensitive only to the appropriate aesthetic objects within their own
restricted field and apparently can feel nothing for other possible aesthetic objects of
beauty in a mathematical equation or sense of awe in the ecology of the myriad diverse
species of common insects gathered on the kitchen screen on a summer evening.
This paper has been an attempt to describe, using a short sample of writing, the
integrated aesthetic aims in Darwin's style and how he fulfills these by combining
diverse kinds of organizing structures. In learning to broaden our definition of style so
that we can begin to understand the range of Darwin's organizing ability and the nature
of his aesthetic criteria, perhaps we are taking the first step toward a way of analyzing
other important scientific literature that has been too long ignored by students of
language and style.
NOTES
1
Theodore Baird, "Darwin and the Tangled Bank," The American Scholar, XV (1946),
477-86.
2
Stanley Edgar Hyman, The Tangled Bank: Darwin, Marx, Frazer and Freud as
Imaginative Writers (New York, 1962), pp. 11-78.
3
The Life and Letters of Charles Darwin, ed. Francis Darwin, 2 vols. (New York, 1898),
I, 80. All subsequent references to these volumes will appear in parentheses in the text.
4
Evolution: The Modern Synthesis (New York, 1942), p. 13.
5
George Douglas Campbell, "The Power of Loose Analogies," The Nineteenth Century,
CXXX (Dec., 1887), 745-65. See especially the critique of Darwin's verbal ambiguities, pp.
750-63.
6
See Baird, p. 478; and Hyman, pp. 26-27.
7
This extract from the original letter, dated Oct. 1857, was published in the Journal of
the Proceedings of the Linnean Society (Zoology), III (1859), 50-53.
8
Chicago, 1962.
9
The Autobiography of Charles Darwin and Selected Letters, ed. Francis Darwin (New
York, 1958), p. 265. p. 154.
10
Kuhn, p. 154
11
Walter F. Cannon, "Darwin's Vision in On the Origin of Species," in The Art of
Victorian Prose, ed. George Levine and William Madden (New York, 1968), p. 165.
12
Alvar Ellegard, "Darwin and the General Reader: The Reception of Darwin's Theory of
Evolution in the British Periodical Press, 1859-1872," Goteborgs Universitats Arsskrift
(Coteborg, 1958), LXIV, 7, p. 29.
13
In the following extracts from Darwin's letters concerning his final editing of the
manuscript of the Origin, we can see his modest and typically mistrustful attitude toward his
writing ability:
April 5, 1859-"This lady [Miss C. Tollett], being an excellent judge of style, is going to
look out for errors for me." (I, 511)
May 11, 1859 "... one lady who has read all my MS. has found only two or
threeobscure sentences...." (I, 512)
June 14, 1859 "I find the style incredibly bad, and most difficult to make clear and
smooth." (I, 514)
June 22, 1859 "You say that you dreamt that my book was entertaining; that
dream is pretty well over with me, and I begin to fear that the public will find it
intolerably dry and perplexing. But I will never give up that a better man could have
made a splendid book out of the materials." (I, 515)
July 25, 1859 "1 think I have got the style fairly good and clear, with infinite
trouble." (I. 516)
Sept. 2, 1859 "I have, as Murray says, corrected so heavily, as almost to have
“The Argument for Organic Evolution Before the Origin of Species, 18301858,” in Forerunners of Darwin 1745-1859, ed. Bentley Glass. (Baltimore, 1959),
pp. 356-414.
14
15
We can try to follow the argument by examining the relations between the
successive assertions that he makes. These assertions are expressed rather informally yet
they follow a careful logical pattern that I am going to express as a chain of hypothetical
syllogisms for convenience, since Darwin often argues with fragments of syllogisms or
enthymemes which make it hard to know the exact type (i.e., hypothetical, categorical,
or disjunctive) of the syllogism in his mind. The assertions that he does not state
formally but seems to assume will appear in italics.
Paragraph 3. Major: if p, then q
If all organic beings born could survive to reach maturity and live out a
normal life span, then "reflect that every being (even the elephant) breeds at
such a rate, that in a few years, or at most a few centuries, the surface of the
earth would not hold the progeny of one pair."
Minor: but not q
But obviously the earth is not so imbalanced and overcrowded as this fact
would suggest.
Conclusion: .". not p
"[Therefore] the increase of every single species is checked during some
part of its life, or during some shortly recurrent generation." Or positively
rather than negatively stated: "Only a few of those annually born can live to
propagate their kind."
(The conclusion of the syllogism above is restated as the minor assertion
of the next syllogism).
Major: if p, then q
"[If] only a few of those annually born can live to propagate their kind,"
then the struggle for life must be intense enough to depend on very slight
advantage..
Minor: p affirmed
And since it has already been affirmed that "only a few... can live...."
Conclusion: .'. q affirmed
"[Therefore] what a trifling difference must often determine which shall
survive, and which perish."
(Notice how a conclusion to one syllogism is drawn into a new syllogism
and logically related to some new assertion in order to imply a further
conclusion, etc., until the chain of logic that makes up the whole argument and
leads to the final conclusion is complete.)
Paragraph 4. Major: if p, then q
If even slight variations in individuals of a species normally occur, then
such profitable variations could be the "trifling differences [that] will decide
which [individuals of a species] shall survive [to propagate]."
Minor: p affirmed
"I cannot doubt that during millions of generations individuals of a species
will be occasionally born with some slight variation, profitable to some part of
their economy."
(Darwin has affirmed this minor assertion with a statement in paragraph 4:
"I believe most beings vary at all times enough for selection to act on them ...";
and even earlier in the first paragraph he had spoken of "the mere fact that in
generation the child is not absolutely similar to its parent.")
Conclusion: .'. q affirmed
"[Therefore] such individuals will have a better chance of surviving, and of
propagating their new and slightly dilferent structure."
(That favorable variations are somehow passed on to future generations is
assumed here by analogy with what happens in domestic breeding, explained
in paragraph 1, but could not be given any firmer foundation until years later,
after Mendel's work in genetic inheritance was rediscovered, elaborated, and
integrated with the Darwinian concept of selection.)
Major: if p, then q
[If certain] individuals will have a better chance of surviving, and of
propagating their new and slightly different structure,... [then certain]
modifications may be slowly increased by the accumulative action of natural
selection to any profitable
extent."
Minor: p affirmed
The conclusion of the last syllogism affirmed that "[certain] individuals
will have a better chance of surviving, and of propagating their new and
slightly different structure...."
Conclusion: .". q affirmed
Therefore Darwin has demonstrated that there is such a thing as natural
selection and its "accumulative action" has been and is operant.
(This completes Darwin's argument affirming with a chain of smaller
syllogisms the minor assertion of the large overall organizing syllogism that he
started with in paragraphs 2 and 3 but has not yet concluded.)
16
On the Origin of Species (London, 1859), p, 459.
17
Cannon appears to conclude that Darwin's logic is "poor" because his premises
are stated informally rather than formally. (See pp. 169-70.) Actually, I think,
Darwin is such an accomplished logician that he can use logic either systematically
or rhetorically, or both at once.
18
Most students of Darwin's style agree that his writing is somehow dramatic.
Both Baird and Hyman suggest that tragedy is the mode of drama in which Darwin
is writing, whereas A. Dwight Culler, "The Darwinian Revolution and Literary
Form," in The Art of Victorian Prose, ed. George Levine and William Madden
(New York, 1968), pp. 224-45, says that the genre into which Darwin's Origin best
fits is comedy. Cannon refutes all three: ".. . the Origin fits no pattern of tragic, or
for that matter, comic action" (p. 154).
19
Darwiniana: Essays and Reviews Pertaining to Darwinism, ed. A. Hunter
Dupree (Cambridge, Mass., 1963), p. 5.
20
"Evolutionary Teleology," in Darwiniana, pp. 293-320.
21
Darwiniana, pp. 121-22.
22
Darwiniana, p. xiv.
23
Origin, pp. 129-30. Though the simile of the Tree of Life is elaborated in the
Origin, both Baird and Hyman find it to be of less importance than the metaphor of the
"entangled bank" in the last paragraph of the Origin. Their criterion seems to be that the
more complex metaphor is the better; both overlook the possibility that Darwin's recreation of a traditional Biblical symbol (placing it in a totally new scientific and
aesthetic context so that it becomes an instrumental metaphor) may be a more important
linguistic act than the creation of a complex metaphor. Cannon dismisses the importance
of the "entangled bank," but, though he takes the Tree of Life simile somewhat more
seriously, he seems to think that it is finally a rather inept reference to a family tree
diagram.
24
Origin, p. 490.
25
A friendly critic, whose name Darwin withholds, found this habit a flaw in the
Origin: "We do not want to know what Darwin believes and is convinced of, but
what he can prove" (II, 36-37). Darwin modestly agreed with him and offered to
"modify the "believes' and 'convinceds'" (II, 37). But the man was horrified: "You
will then spoil your book, the charm'of it is that it is Darwin himself" (II, 37).
26
Journal of Researches (London, 1,845), pp. 391-98.
27
Darwin might also have preferred not to use "transmutation" because it had
become identified in people's minds with the discredited evolutionary theories of
Lamarck and R. Chambers.
28
This characteristic of his writing i.e., considering the merits of opposing points of
view with care and tact seems to have grown out of one of his working habits. Darwin
says in his autobiography: "I had, also, during many years followed a golden rule,
namely, that whenever a published fact, a new observation or thought came across me,
which was opposed to my general results, to make a memorandum of it without fail and
at once; for I had found by experience that such facts and thoughts were far more apt to
escape from the memory than favourable ones." (I, 71)