Sunday, April 4, 2010

4/5: What do we mean by evolution?

Last Update: 04-06-2010 18:19:48

The concept of evolution is much broader than the work of Charles Darwin. What are some of the specific ideas that come under the broad heading of evolution? What are the early origins of these ideas and how do they recur or develop over the centuries?

Before Charles Darwin's On the Origin of Species (1859), there was plenty of evolutionary theorizing: Cuvier, Lamarck, Geoffroy St. Hilaire, Richard Owen, Robert Chambers, Darwin's grandfather Erasmus Darwin, and many lesser lights. (And also many anti-evolutionary theorists: most famously William Paley, Cuvier (who can be counted in both camps) and Agassiz.) With or without Darwin, evolutionary ideas were gathering force, evolution was becoming a cultural/intellectual obsession. Darwin was huge, but evolution was huger.

Before Darwin ever wrote about the word “evolution,” related and privileged cultural categories were developing—“science”, “progress”, “art”, “modernity”—which received representation and were performed in all sorts of representations and visual displays. Evolutionary theorizing was already well underway before Darwin ever entered the scene. There was already a widespread belief that human beings had entered a new age—modernity—and were transforming the world, and being transformed, by “Progress” in science, art and civilization, some feeling that a metaphysical force had over natural time transformed nature and now was transforming humanity. This was the discursive soil in which evolution sprouted. After Darwin became the world’s most famous evolutionist, these cultural categories continued to nurture evolutionary thought, belief, discourse, image-making: most people knew the name of Darwin, who became the personification of the evolutionary idea, but most did not read Darwin or know what he was arguing. They got his arguments second or third or fourth hand or not at all.The idea of evolution, in evolutionary discourse, evolution talk, and evolution images, grew nonetheless (eugenics was a potent nutrient solution, but there was also literary realism, psychoanalysis, Marxism, modern art), a big idea filiated with other big ideas about progress, civilization, science, modernity, the primitive. Big ideas which induced some mixture of intoxicated pleasure and deep-seated anxiety.

Erasmus Darwin (1731-1802), The temple of nature; or, The origin of society: a poem, with philosophical notes (1803; Baltimore, 1804). Engraving: Henry Fuseli (1741-1825). In this book-length poem, Erasmus Darwin argued that life, society, and human reason were continually evolving and improving. He died seven years before the birth of his grandson, Charles. The image symbolically shows the dramatic but only partial unveiling of a bountiful (three-breasted) Nature.
Carolus Linnaeus (1707-1778), Systema naturae (1735; Stockholm, 1748), 16-17. Linnaeus, the Swedish naturalist, devised a classification system, still in use today, for arranging the natural world into a fixed hierarchy of kingdoms, classes, orders, families, genera, and species. While not an evolutionist, he contributed to the development of a visual vocabulary and visual descriptive practices that provided the resources for the development of evolutionary theory. The Anatomy of the Human Gravid Uterus (Birmingham, 1774). Copperplate engraving. William Hunter (1718-1783) [anatomist]; Jan van Riemsdyk (fl. 1750-1788) [artist]. Credit: National Library of Medicine. An eminent anatomist and obstetrician, in this study Hunter confined himself to a specific topic (late pregnancy) and “subject” (the dissection of a woman who died near the end of term). Illustrations that represent only “what was actually seen,” Hunter argued, will carry “the mark of truth” and be “almost as infallible as the object itself.” Close description of natural objects in scientific illustration was one of the key practices of 18th- and 19th-century scientific visual culture and a key resource for Darwin, Cuvier, Geoffroy St. Hilaire.

What is evolution? Like Gaul, the answer is best divided into three parts. First, there is the fact of evolution. This is the claim that organisms, those living and those dead, were not created in one fell swoop, miraculously, but came about through natural processes from other organisms very different. It is thought that the Earth is about 4½ billion years old and that life here on earth started about 3¾ billion years ago. It is not absolutely essential, but today claims about the fact of evolution would almost certainly include claims about the arising of life from inorganic matter by natural processes. “Natural” in this context meaning according to unbroken law and not through “supernatural” or God-intervening processes. (Nothing is being said ultimately about God’s existence. It is rather that in talking about evolution one is keeping God out of the process. Denying God is metaphysical naturalism; not talking about God is methodological naturalism.)

Second there is the path of evolution. Following Charles Darwin, and indeed before him, the usual picture is of a tree of life. All organisms come from one central stem, and then diverged and developed from there. The earliest organisms were the simplest and complexity grew through time, although obviously simple organisms also persist. It should be noted however that not every evolutionist shared this vision. The early nineteenth-century, French evolutionist Lamarck saw evolution as a series of parallel lines upwards, with new life starting over and over all of the time. Today, it is generally agreed that it is possible to have genetic material (genes) transferred laterally between branches of the tree, courtesy especially of viruses. One should not overestimate this however. Humans did not evolve from monkeys thanks to large infusions of oak tree genes.
Third there is the cause or mechanism of evolution. Today, thanks to Darwin’s Origin of Species, general opinion is that the chief cause is natural selection or the survival of the fittest. More organisms are born than can survive and reproduce. This leads to a struggle for existence. Success in the struggle is on average a function of the different characteristics of organisms, and overall this leads to change. Most importantly the change is in the direction of adaptive advantage – eyes, teeth, bark, leaves – features that enable their possessors to succeed.
It has never been the case that evolutionists think that natural selection is the only cause of change. Darwin introduced a secondary mechanism, sexual selection, which involves competition within species for mates. He also believed in the now-discredited Lamarckism, the inheritance of acquired characteristics. Today, especially at the molecular level, it is believed that chance facts can be important. This is the theory of molecular genetic drift.
Obviously the three parts are not entirely separate. If you believe that selection is important, then you see evolution as essentially smooth and continuous. Instantaneous major changes take organisms out of adaptive focus and hence are impossible. If you believe that evolution is tree-like then you have got to have subsidiary mechanisms to explain the branching. Why would organisms split into different groups and go their separate ways? But the division is a help to understanding one of the most wonderful discoveries made by humankind. Thanks to evolution we humans know we are primates. Finding out about evolution shows that we are pretty special primates!

As an astronomer I would like to put "evolution" within a larger cultural and scientific context of cosmologies.
Today we work within the framework of the Big Bang model of the evolution of the universe, and there is a large amount of observational evidence that supports this model ( though there are discrepancies currently with the mysteries of dark matter and dark energy).

Todays Big Bang theory traces its contemporary roots to the work of catholic priest George Lemaitre who wrote about an expanding universe from a primeval atom ( in the early 1920s).

For many decades prominent scientists resisted the evidence and there were many attempts to rescue a "steady state" universe.

The concept of the evolution of the universe rather than a static "perfect" universe have, of course, a very long and controversial cultural history, part of the change of our cosmologies embedded in our cultural and religious systems. The evolution of the universe as a concept in astronomy has as difficult a social history as in biology ( though we astronomers dont have the equivalent of eugenics ).

A deeper underlying issue is whether the world is understandable by science (Wigners mysterious effectiveness of mathematics). Evolution as a concept provides a very powerful explanatory system both in astronomy and biology.
This seems an excellent moment to bring visual culture into the discussion. As Michael Sappol pointed out, before Darwin there was a great deal of theorizing about evolution, and artists were also involved. A close look at paintings of monkeys (singeries) in the 17th and 18th centuries preview themes about evolutionary origins. The painters of singeries could intimate common origins between men and monkeys in a way the scientists could not, and who were denied such views by the Church. The anthropomorphism exhibited in monkey paintings by Brueghel, Teniers, and Chardin is at odds with observations of monkeys in their natural environment, yet encourages fruitful scientific analogies. In 1793, Buffon wrote of the ape in Histoire Naturelle, that "he is a degenerative man, that man and ape have a common origin." The Church forced him to repudiate this view, but artists were not as readily censored. For those interested in further information, these ideas were published in 1986 in “Monkey in the Middle: Pre‑Darwinian Evolutionary Thought and Artistic Creation” (Levy E, Levy DE), Perspectives in Biology and Medicine, 3:1, 95‑106.
Image caption: David Tenniers II (1610-1680), "Guardroom Scene with Monkeys" portrays a guardroom. In this series a monkey society has mastered aspects of toolmaking, administration of medical aid, and fire-making.
What I've been arguing in my posts is that we should historicize this question ("what do we mean by evolution") and move Darwin off center-stage for a moment. Before Darwin, evolutionary theory was debated as transformism of species via adaptation (Lamarck, Geoffroy St Hilaire) vs. fixity of species (William Paley, Cuvier). After Darwin there was a third position: natural selection over geological time. And a lot of confused thinking about evolution which mixed up all the positions.

To rephrase the question: Before Darwin ever got going, how did people talk about evolution, transformism, progress, etc.? And how did they represent those things visually? What visual practices were implicated in the development of evolutionary theory? One of the most important visual practices was careful and precise representation of organic forms in copperplate engraving. Such illustrations were a form of visual rhetoric that was never innocent of theoretical bias. The transformist position was that different species were all variations of a common plan that changed over time to adapt to the environment.
Below is a plate from 1818 (when Charles Darwin was 9 years old) that visually illustrates and compares anatomical specimens to argue the transformist point...
Image caption: Geoffroy Saint-Hilaire, Étienne. Philosophie anatomique. Des organes respiratoires sous le rapport de la détermination et de l'identité de leurs pièces osseuses. Paris, 1818.Bibliothèque Interuniversitaire de Médecine et d’odontologie) (BIUM).

Yes, perhaps we can begin to look at cultural evolution and the ways in which contingency and chance, along with intentionality, become part of the process of change. In the cultural sphere, predictive outcomes seem to escape analysis. The inter-subjective, coupled with underlying alterations in economic, social and political matrices come into the fore through diverse critical readings and cultural studies. Such modes of knowledge, eventually seep into public consciousness, in which they are altered once again. Who can predict the future of culture's idiomatic presence?

I love the diagram, which shows how evolutionary discourse shaped self-conscious modernist mid-20c art practice and critical thinking about art. Both the content (the evolutionary tree) and the aesthetic (Bauhaus-style new functionalism) contribute to a modernist sense that art is evolving in the direction of high modernism. (I've seen it before but can't remember the source: where does it come from?) It also reminds us that diagrammatic/schematic representation played a big role in both the production of primary evolutionary discourse and its proliferation.
Dear Michael and Kevin,
This chart is the front cover of a catalogue entitled "Cubism and Abstract Art," (1936) an exhibition curated by M.O.M.A's first museum director, Alfred Barr, Jr. This chart tells us much about the direction that Barr envisioned for modern art, as it reached its stated goal of abstraction. It shows us a stream-lined ideology of " high" art, both denotatively and connotatively . However, it also points to other parallel practices at that time, such as the emergence of a no-frills industrial design movement and the rise of eugenics in America. I think that as an example of "visual culture" it references not only what is made visible, but also to other social practices embedded in the culture.
I want to reinforce Michael's earlier comment. At this stage in the symposium we want to focus on pre-Darwinian ideas about evolution. Many of the themes will be part of our discussion of the present and future, but let's wait before we dive into that. Some grounding in history will he a useful foundation for that discussion. Also, keep in mind his inclusive description of visual culture. Trends in garden design, for example, could reveal a great deal about a society's ideas about the natural world.

Regarding both the question “What is evolution?” and Kevin’s injunction to stick to the 19th-century/neo-Darwinian period (rather than, say, ongoing NeoDarwinist theories in the 20th centuries), I want to mention less scientific views, such as the sociological perspective of Herbert Spencer and his influential publications and the economic treatise The Wealth of Nations by Adam Smith. How did seemingly scientific ideas about evolution negotiate and align with the strong western cultural/religious desire for a teleological end, one that would bring some sort of salvation/security to groups struggling for resources and rewards in a burgeoning and rapidly transforming capitalist structure?

This teleological assumption persists to a decent degree into late 20th- and 21st-century debates about design, direction, random mutation versus adaptive change, and recent interpretations of natural selection that open room for current interest complex systems (sorry, Kevin… we can return to this later of course – I’m thinking of Depew and Weber’s book Darwinism Evolving). At root is western culture’s deeply held faith in “progress,” definitions of which often entail so-called “advanced” technologies (whose constant invention and re-creation drives capitalist economies). So, just as my contribution to the “What is visual culture?” thread pointed out how the visual culture/art historical disciplines are negotiating the high/low, elite/mass culture issue, so too in our thoughts about “What is evolution?” are we faced with a deeply prevalent assumption that human evolution/progress is towards the high-tech, cyborgs, etc. rather than a low-tech approach to sustainability.

But back to the 19th century...

Christina raises several of the questions we will be exploring later, and Michael Ruse currently has a very interesting piece on E.O. Wilson, sociobiology, Spencer, the idea of progress, and other topics on the website of Chronicle of Higher Education. We have a lot to look forward, so I appreciate Christina's restraint. We will get there eventually.

To pick up Roger Malina's comment about cosmologies, Robert Chambers' anonymous Vestiges of the Natural History of Creation (1844)--which appeared just after Darwin had written a full sketch of his theory--explicitly combined the "development" of life with the development of the universe. Indeed, Vestiges' use of the "nebular hypothesis" added to the controversy surrounding it. Herbert Spencer, too, of course, made cosmic evolution a major component of his version of the doctrine of development. One of the striking absences in Darwin's work is just this sort of cosmic perspective.

Under the hood of evolution is the creative engine of life. That engine was described by the Pre-Socratic philosophers, Romans and ancient Chinese in various ways using an assortment of names, some of which still grow in our imaginations today. For instance, the Greeks envisioned a thing called the “arche,” which could be water or air or even earth. It was something tangible that they thought all forms of life needed, in order to grow and survive. Arche meant the “beginning” [of something]. I gather from the general descriptions, the concept served as a universal seed of sorts. To mix metaphors, it was one of the fuel sources of life’s engine.

It would be interesting to trace the evolution of the arche concept, from the views of the Milesian monist, Thales, to the time Darwin was seeking insights into nature’s way. How did this fundamental concept, which linked the growth of plant and animal life alike, change? And can we spot any remnants of this concept in Darwin’s visual notations?

As I absorb Darwin’s sketches, it seems as though he thought of evolution as an endless surprise that life forms experience as they interact with their habitats. Perhaps, he regarded evolution as a synonym for surprise, including the surprises that change and transformation yield—however, slowly or rapidly, fluidly or in abruptly. Maybe the arche became something as essential and vital as “the element of surprise” that keeps the whole Animalia Kingdom on its toes—like this fearsome species, V. komodoensis, the Komodo dragon (picture above), which is notorious for hunting and ambushing an array of prey: from invertebrates to mammals.

It barely matters to me that Darwin was not the first to wrap his mind and passions around the exploration of nature’s patterns of growth. But his beautifully evocative drawings of the living, evolutionary artifacts he encountered on the Galápagos Islands suggest that he was one of the first explorers to succeed in galvanizing the public’s imagination along with his own about the possibilities and implications of natural selection. Darwin didn’t need to wait a hundred years to verify his hypotheses and test his experiences. He intuitively leaped and grasped the principles of natural selection, which he defined as the mechanisms by which nature experimented with the growth, size, shape, variety, dynamics, and habits of all life forms. Maybe the arche concept eventually evolved and morphed into this mechanism of change that Darwin’s sketches capture, and that we naturally relate to all biological and physical matter.

The dragon is an amazing creature that was produced--we all agree--by an evolutionary process, and this is an amazing photograph. Todd's historical narrative is a grand vision, in many ways similar to the grand visions of Erasmus Darwin, Louis Figier, and others, but evolution didn't just force itself on human consciousness. Evolutionary discourse--the evolutionary idea--was not inevitable. It was produced in a particular historical time and place--out of the materials that were available and in response to very particular historical scientific and political problems. One of those materials was the practice of tabular and schematic presentation which had developed greatly in the period between1500-1850. Attached is Darwin's printed tree diagram, but his diagram followed on the heels of many other similar diagrams which were made to show historical and natural relationships.
Image Caption: Charles Darwin, On the Origin of Species (1859).

All the wonderful ideas whizzing around here inspire me to wonder how our concepts of evolution will continue to change, as our timekeeping mechanisms for measuring evolutionary processes change. Surely, from those distant times in Egypt (say, 1500 BC), where the shadows of time were once clocked by observing the subtle passage of light cast across a T-square measuring tool, to the present day, where our phenomenally sensitive atomic clocks measure time in attoseconds (10-12 s), our perceptions of evolution have changed.
To rephrase my simple question: how will our concepts of evolution change as our capabilities advance for measuring more and more physical phenomena in far greater detail and in smaller increments of time – while simultaneously seeing the interconnectedness of these phenomena? Given that atomic clocks keep pace with the beats of time (“accurate to seconds in many millions of years”), will we eventually reach some threshold of evolutionary change that we can no longer measure? And yet, we’re still likely to sense that this particular threshold holds the secret to understanding the reality behind timespace and evolution; specifically, the tangible influences both have on one another.
In other words, can you imagine reaching a point in our intellectual and technological growth where time no longer “separates cause and effect”? This wild thought was sparked by that playful truism Woody Allen ventured, “Time is nature's way of keeping everything from happening at once,” as he echoed the words of Albert Einstein and John Archibald Wheeler.
When you consider the light speed of our thoughts-in-action today, I’m certain many people feel as though they’ve already reached that threshold for real! No doubt, Murphy's Quantum Law – “Anything that can, could have, or will go wrong, is going wrong, all at once!” -- was born in such a fleeting moment of impossibility. Perhaps, a new understanding of evolution will be born in that instant, too.

04-06-2010 18:19:48
I have been following with great interest the various streams of consciousness in this subtopic of “pre-Darwin evolutionary thinking,” and I would like to offer some comments thereon. As Kevin has reminded us, at this stage we should keep in mind the following precepts: 1) the subject is “pre-Darwin” views, and 2) “visual culture” is the other half of the story.

As expounded by Michael Ruse and by Michael Sappol, “evolutionary thinking” (contrary to the perception/suspicion/accusation of the public at large today) did not begin with Darwin. Yes, he did synthesize a grand Weltanschauung, entailing a causative schema, and brought the issue to a head. But even this enterprise was not altogether original, as Alfred Russel Wallace came-up with essentially the same model independently of Darwin. We should always place the word “evolution” in quotation marks in pre-Darwin times. This term did not become popular till the latter part of the 19th century, and Darwin himself did not introduce it. As emphasized by Ruse and Sappol, “evolutionary thinking” was very much in the air long before Darwin, under such operative expressions as species “transmutation” or “transformation.” In scientific circles at the time, the focal point was (what historians now refer to as) the “species problem.” The long history of the voyages of discovery by the reigning naval superpowers of times past had opened the minds of enlightened observers to the huge diversity of the world’s biota – both animal and plant life forms. The emerging science of comparative anatomy revealed the similarities of structure-and-function of living beings and, moreover, suggested tantalizingly that there were divergences and convergences therein. Biogeography (also a newly emergent field) indicated that the morphological features of species were correlated with their local environment. As the “tree of life” (discussed, for example, by Ruse) unfolded, the fundamental question arose: Is this tree static or dynamic? If species change, what is the mechanism? Does humankind sit (nay, reign) at the “top” of the tree? Christian religious dogma – especially the literalist interpretation of the biblical Genesis account – was a dominant theme (and remains an undercurrent today).

Todd Siler discussed the issue of time. Time entered into pre-Darwin “evolutionary thinking” largely through the study of the earth’s strata, along with the observation of fossil remains embedded therein. There was mounting opinion that the “time” required for the formation of the strata must be MUCH longer than that suggested by a literal reading of the Genesis story in the Bible. The “time” element was crucial to “evolutionary thinking” early on, as it was becoming apparent conceptually that species must change very slowly, compared to the flow of time in our everyday lives. Guestimates of the time-frame of species transmutation, at the time, varied wildly, as there was no really accurate way of gauging the age of the earth then. (The temporal question would resurface in the latter part of the 19th century.)

It is hard to over-estimate the importance of visual culture in early, pre-Darwin “evolutionary thinking.” Evolution, even today, is not a scientific subject that can be readily explored experimentally in the laboratory (save for simple biochemical and genetic microbial studies) – “time” being a factor. As told by a number of contributors to this symposium section, the sketches, drawings, and water-color paintings of the early “naturalists” (including Darwin himself) proved invaluable in illustrating both the diversity of life and its defining morphological attributes. Comparative anatomy was ruled by the skill of the illustrators. The supreme talent displayed by the “installation art” in the zoological and botanical museums and gardens in Europe and the UK was profoundly important. Aside from Nature per se, these museums and gardens, along with the colorful depictions of life in the “wild,” were, in fact, the arena for pondering species evolution.


04-10-2010 07:09:15
This is not really my area and I'm late to the discussion so forgive the somewhat tendentious provocation. It's just an idle musing as to whether the fact that Darwin was a man and a man of his time generated an account of evolution as a heroic narrative with the species as protagonist. Maybe that blocked for a time some of the insights of ecology (that the environment in which species evolve is itself made of evolving species). Of course there was always the 'tangled bank' and maybe it was the advent of numerical simulation and the computational power that enabled large scale modelling which liberated the biology from its historical context.

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