Multiple layers in influencing an audience: The case of Darwin's On the Origin of Species


1. Introduction
Having been sensitized to the story telling aspect of scientific writing, to the dominant structural themes adopted in accounts or origins, and to the ideas of nature that were invoked before Darwin to support ideas of the social order (whether that was the actual, idealised, or desired order), we are now in a better position to read Darwin and interpret his ideas on evolution and on the means by which it occurs.

1b. Mini-lecture: Given that one of the things Darwin did was write to convince his various audiences, this lecture introduces 4 layers of argument in Darwin's text and models close reading of the introduction and part of chapter 1.

2. Reading
Darwin, C. (1859 [1964]). Introduction & Chapters 1, 3, part of 4. In On the Origin of Species. Cambridge, MA: Harvard University Press, 1-43, 60-96. (Available widely on the internet or via password-protected readings.)

This is the first full-length treatment that Darwin published of his theory of natural selection. He is carefully building up an argument so let us read closely, assuming that everything has a point. In class we will unpack the multiple layers of a scientific theory, in this case, the argument, analogy, metaphor, and defences. To prepare for this, make a copy of the following table and fill in the right-hand column as best you can from your reading.

 Fill in your understanding & provide quotes that illustrate or support it
Layer 1: premises leading to conclusion that evolution results in improved adaptation to local conditions
2 majors premises of Chapter 1 & 2
1 major premise of Chapter 3 & its consequence
1 major premise of Chapter 4 & in combination with preceding premises, its consequence
Layer 2: analogy
Given the lessons of Chapter 1 about selective breeding by humans, namely,..
then something like selection in nature should be effective because…
Layer 3: metaphor of Natural Selection
Associations that help readers conceive of this mechanism working so that evolution results in improved adaptation to local conditions
Associations that help readers see that what they had learned from Natural theology can still be explained
Associations that might not work in Darwin’s favor
Layer 4: preemptive defences
Against objections from other naturalists and scientists
Against objections from religious authorities
Other issues or questions you have


3. Activity
Clarify and extend what this scaffolding helped you learn from the reading.

4. Synthesis and extensions

A recapitulation of the early chapters of On the Origin of Species

(from Taylor P. J. 1998. Natural Selection: A heavy hand in biological and social thought. Science as Culture 7:5-32)

The Origin is about evolution, about how the diversity of forms we observe are descended from common ancestors through a series of modifications over time. Darwin's purpose was not merely to establish that evolution existed; many before him had noted the changes in fossils from one layer to the next. As he wrote in the introduction, his central problem lay elsewhere:


Darwin had to provide a convincing mechanism for evolution, and, moreover that mechanism had to account for adaptation-such as the long antennae which enable blind cave crayfish to sense their way in the dark. His contemporaries drew their conventional wisdom from Natural Theology. The adaptation between organisms and the environment, so marvellous and harmonious, necessitated a designer; adaptation was evidence of God. Darwin's counterproposal to explain adaptation and evolution was, of course, natural selection. Given the absence of direct evidence of natural selection actually happening, however, it was no small task to win his readers over to his theory. So he advanced on argument which has several layers. The centrepiece of this argument is laid out in his first four chapters which I will recapitulate in sequence.

In Chapter 1, entitled 'Variation under domestication,' Darwin observed that variation exists in the characters of organisms such as in the size of udders of cows and goats. Variation never runs out, though its causes are unclear (Darwin believed that new environments acting on the reproductive system elicited new variants). Variation existing in parents often appears in offspring, even if it does so imperfectly and mysteriously, sometimes disappearing only to reappear in later generations, e.g. baldness in grandparent and grandson. In short, variation among organisms exists and is partially inherited in offspring.

Darwin developed his observations of variation further: Variation can be accumulated. Darwin described in detail the extreme differences among the runts, tumblers, pouters, and so on at the London Pigeon Club. Darwin speculated that if ornithologists were to encounter different domestic pigeons back in the wild they would classify them into different species or even into different genera. Yet, it seems, all domestic pigeons are modifications of one species of rock pigeon; one ancestor had, over a long period of time, given rise to all the diversity of descendants. The divergence from the common ancestor was brought about by humans selecting variants and moulding the lineages of animals to human wants and fancies. The accumulation of differences occurs in small steps, not all at once. Sometimes the differences are imperceptible except to the specialized breeder and may even occur unconsciously. In another example, Darwin wrote of Mr. Buckley and Mr. Burgess both sincerely striving to breed true from the same original stock of Mr. Blakewell's Leicester sheep, yet after fifty years their two flock looked quite different (p. 36). And so, such stories of the effectiveness and gradualness of selection by humans make up the first chapter of Darwin's book about evolution in nature.

Chapter 2, 'Variation under nature,' can be summarized for our purposes as: variation also exists in undomesticated species and tends to be reproduced in offspring.

Chapter 3, 'Struggle for existence,' begins with Darwin rewriting Malthus from society into the natural world. Organisms tend to increase their numbers exponentially; in 500 years one pair of slow breeding elephants would, Darwin calculated, multiply to 15 million animals. Resources do not, however, match this increase, so not all offspring can survive. Because of this 'hyperfecundity' (a modern term, not Darwin's) among the offspring there must be a struggle for existence. Darwin used this term in 'a large and metaphorical sense' (p. 62). Existence included success in leaving progeny. Struggle included getting food from other organisms, coping with drought, competing with other animals for food in times of scarcity, a parasite's finding of a host, and so on. Darwin noted that competition is strongest among individuals of the same species and in other situations is generally less focussed. Darwin observed, taking what we would now call an ecological viewpoint, that checks and relations among organisms are very complex and can produce unexpected results. For example, the introduction of one species, Scotch fir, into heathland led to the flourishing of many species of plants, insects, and birds not previously seen in the heath (p.71). Furthermore, as if the harsh connotation of the term struggle needed mitigation, Darwin began the chapter by reminding the reader about the exquisiteness of adaptations evident in the 'humblest parasite [clinging] to the hairs of a quadruped'(p. 61). And he ended with the wonderful reassurance that when 'we reflect on this struggle, we may console ourselves with the full belief, that the war of nature is not incessant, that no fear is felt, that death is generally prompt, and that the vigorous, the healthy, and the happy survive and multiply' (p. 79).

But, if not all offspring can survive, which survive? Chapter 3 posed this problem; chapter 4, 'Natural Selection,' resolved it as follows: In the struggle for existence those with favourable variations are preserved, and those with injurious variations are rejected. Or, in Herbert Spencer's phrase, the fittest survive. Darwin, however, preferred his name for the process and thoroughly exploited the likeness of Nature to a Selector:


Nature the Selector is, he added, immeasurably superior to Man:

An interpretation of the layers of Darwin's presentation


(from Taylor P. J. 1998. Natural Selection: A heavy hand in biological and social thought. Science as Culture 7:5-32)

Now that we have a first reading of Darwin's argument for natural selection as the mechanism for evolution, let me unpack the multiple layers therein. The first layer is a straightforward deduction. If we have evidence of variation, inheritance of variation, and hyperfecundity, then there must be a struggle for existence. And, in the struggle, if those more fit to the conditions of life survive and reproduce, then the next generation of offspring will on average be better adapted to those conditions. Notice, for I will return to this later, that this deduction comes in two logical stages.
1) Variation, inheritance and hyperfecundity on their own imply only that there will be differential representation of variants from one generation to the next. (This could lead nowhere in particular.)
2) Survival (and implicitly reproduction) of the fittest, or natural selection, tends to give us, in addition, improved adaptation.

The second layer of Darwin's argument is the analogy. Chapter 1 in all its length serves to impress on his readers that selection is effective under Man. Given that the same elements exist in Nature, and act even more strongly, selection should, according to the analogy, be effective under Nature.

The third layer is the metaphor of Nature as Selector. Metaphors are devices that animate thinking about one concept through the connotations of another. What would have been the connotations of a Selector to Darwin's readers? First, he was appealing to an audience well versed in Natural Theology and the use of Nature as evidence of God's design. Darwin's mechanism for evolution eliminates the need for a designer and might seem radically opposed to Natural Theology. However, if Nature were seen as God's handmaiden, then Darwin could be read quite comfortably as another interpreter of natural laws laid down by God. Furthermore, English Natural Theology had become decidedly anthropocentric, with God designing the world for the benefit of humankind-utility was as important as harmony in this design. To an audience well aware of the active shaping of plants and animals by selective breeding, the invocation of a Selector would have rung true. Darwin's audience was also a bourgeois audience, susceptible to appeals to universal man, and able to use discussion of the abstract rights of all men to insulate itself from the actuality of industrial and imperial exploitation, slavery, and the subordination of women to men. A unitary Nature, therefore, resonates with this unitary Man; Natural Selection, in contrast to the decentered, unfocussed connotations of the term 'survival of the fittest,' cuts through the complexity of checks and relations to become a singular and abstract force (Williams 1980, see also Young 1985a,b, 1993).

Such connotations were felt unevenly and with qualifications by Darwin's different contemporaries. The power of metaphor is precisely that connotations are neither dictated nor unambiguous. Let me add two other important connotations invoked by Nature as Selector, ones that caused problems for Darwin's theory. The first is progress. Selective breeding is also called plant (or animal) improvement; selective improvement is progress. Darwin seemed to recognise, however, that adaptation to local circumstances did not guarantee unidirectional, global progress. He avoided the term evolution which associated change with a steady overall improvement. (This connotation persists to this day...) Darwin’s guard slipped in the Origin only once, when he used 'evolved' in the concluding passage of the book. There he exalted readers to see not pointlessness in the struggle for existence, but 'grandeur in this view of life' in which, 'from so simple a beginning, endless forms most beautiful and most wonderful have been, and are being, evolved' (p. 490). However Darwin's contemporaries did not match his caution. Evolution as popularized by, for example, Spencer in the Anglo world and by Ernst Haeckel in Europe was equated with progress. We need only think of the common pictures of marching sequences of primates from an ape to a human (almost always a man), or of the trees of life at whose crown usually the human species, not other quadrupeds or multicellulars, and never bacteria.

A second problematic connotation of Nature-the-Selector proved most difficult for Darwin's theory. God-the-designer, the god of Natural Theology, is a god created in the image of Man–conscious and able to design. Natural Selection, however, proceeds unconsciously. So, if Nature-the-Selector replaces God-the-designer, the special position of humans in the natural order, next to God, is undermined. Humans become just another species, perhaps the highest point in evolution, but continuous with other species and subject to the same laws; in other words, there is a uniformity in nature. Young (1985) argues that the issue of continuity or uniformity, more than any other issue, led to the lack of acceptance by Darwin's contemporaries of natural selection as a mechanism of evolution. When the sixth edition of the Origin was published in 1872 Darwin had hedged significantly from his original exposition, adding mechanisms other than natural selection to explain adaptation. Most notably, he accepted a significant role in evolution for the Lamarckian idea that modifications of an organ through use or disuse during the parent's lifetime could be passed to offspring-an idea, ironically, much closer to human ideas of conscious improvement.

So we see that Darwin's metaphor was very active, and that some of its many connotations were problematic for Darwin's contemporaries, and even for Darwin himself (Young 1993). Why, we might ask, was the metaphoric layer of his argument so prominent? Why not focus, as modern biologists do, on the first layer I mentioned, the seemingly straightforward deduction? To Darwin the conceptual, scientific problem was that, although there was evidence for variation, inheritance and hyperfecundity, and although survival of the fittest seemed eminently plausible, adaptation by natural selection was only a deduction from these elements–he had no direct evidence for natural selection actually in process. The lack of evidence accounts for a fourth layer in Darwin's writing–his numerous defensive moves. When in Chapter 1 he spoke of imperceptible differences, of divergence resulting from a slow and gradual accumulation of small steps over a long period of time, he was saying, in effect, 'don't expect to see natural selection happen before your eyes.' And, by stressing the complexity of checks and relations in the struggle for existence, we can hear him asking readers not to expect him to define exactly what makes one organism more fit than another: 'Simply take it like this–Some must be fitter, no? And, if the fitter survive and reproduce, then the process will look as if there were a selector.'

References:
Williams, R. (1980) 'Ideas of Nature', p.67-85 in Problems in materialism and culture. London:Verso.
Young, R. (1985a) 'Darwinism is social,' in D. Kohn (Ed.), The Darwinian Heritage. Princeton, NJ: Princeton University Press, 609-638.
Young, R. (1985b) Darwin's Metaphor: Nature's place in Victorian culture. Cambridge: Cambridge University Press.
Young, R. (1993) 'Darwin's metaphor and the philosophy of science', Science as Culture 3: 375-403.

Additional question to consider in order to delve deeper into Darwin's writing in the social-historical context in which it was written:

Darwin, C. “Chapter 5, On the development of the intellectual and moral faculties during primeval and civilised times,” Pp. viii-xxi, 158-184 In The Descent of Man, Princeton, NJ: Princeton University Press, 1981.

Evolution matters in thinking about humans and their social arrangements because they can be made to seem natural, and thus not requiring of social justification or change.
If social Darwinism is construed broadly as attempts to naturalize aspects of society, then Darwin was a social Darwinist.
The Descent of Man is not just a founding text in the science of sociobiology. Yes, his theoretical innovations (relative to the Origin)—reciprocal altruism, kin selection, group selection, cultural selection—foreshadow work going on today. But, these and the central structure of his science (to follow) reflect his desire to show that features of Victorian society (e.g. imperialism, poverty, meritocracy, Anglo-Saxon superiority, monogamy) were as they should be.
The structure of his work consists of five strands:
1. Victorian society is as it should be.
2. Natural selection is mechanism of evolution plus adaptation.
3. Panglossianism (from natural theology): everything is adapted.
4. Story telling to fill in gaps.
5. Naturalism: humans in society are subject to natural laws.
  • which come together in showing:
Features of society are produced by natural selection,
  • even though this requires Darwin to
    • invent functions for the features, and
    • invent historical stories in accordance with natural selection (expanded to include the extra innovations) for the origin of those features.

If you think Darwin might have been able to argue that natural selection explains social behavior without weaving in all these strands, reread the selections from Descent and note the metaphors he uses, the "facts" about higher and lower people and characters he chooses to explain, and the features whose explanation requires him to introduce the extensions to natural selection. We do not have to think Darwin was impure or just pleasing his audience. Instead, we can interpret the projection of society into science via the following multiple routes:

Ideas about social order, social "problems," and social change facilitate the scientist's work by
  • getting them interested in a topic and generating questions
  • getting an audience interested in the topic and generating further support and discussion -> continuing work
  • setting the categories and terms and excluding potential evidence that might not fit
  • setting the questions
  • rendering plausible what otherwise might need evidence to support it and thus avoiding thorny issues
  • providing stimulating metaphors (that can eventually turn out to be restrictive)
  • allowing them to base parts of their work on data or results (e.g., skull size measurements) that were are accepted at that time but now are seen as strongly biased
  • getting feedback from dominant social groups (in funding, institutions, publicity, public policy)
Eventually some time later scientists may be able to dissociate some of the scientific ideas from their original sources of social support. However, that does not undermine the argument that scientific work is woven out of many social strands and may have developed differently in different social circumstances. Moreover, some of the weaknesses in Darwin, e.g., ascribing to humans as a species some culturally specific quality, are worth being on the lookout for in current sociobiology, not to mention everyday speech and perceptions.
5. Connections and resources
Additional readings
Moore, J. (1986). "Socializing Darwinism: Historiography and the Fortunes of a Phrase," in L. Levidow (Ed.), Science as Politics. London, Free Association Books, 39-80.
Taylor, P. J. (1998). "Natural Selection: A heavy hand in biological and social thought." Science as Culture 7(1): 5-32.

5b. Add to this blog post to make contributions to the revision of the chapter above or to an annotated collection of readings and other resources related to the chapter.
5c. Adaptation of themes from the chapter to students' own projects of of engaging others in learning or critical thinking about biology in its social context. Suggestions for how to do that:
i. Identify a key author in your area and examine the premises and logic, analogies, metaphors, and defensive moves in a key writing of that person.
ii. Others TBA