Tag Archives: autonomy

The moral of the story of how we came to be – 1

Tom Clark


Please note: this commentary, recovered on 28-Jan-2017, was originally published in Science Dialogues on 17-May-2015.


From our one short lifetime, we look back and wonder “How did we get here?” This matters because we also want to know “What are we doing here?”  Our imaginations squint to make out answers.

Looking back to the way we got here, we try to imagine the magnitude of time and the qualities of changes that made up the past. Our views are limited not only by the shortness of our lifetimes, but also by the stories we tell about the view backwards through the keyhole of our lives.

We have portrayed the past in our own image, assigning nature’s varied powers to a single human-like God who put us here for a reason and authorized our dominion over life. Exaggerating how much purpose has been a part of our story, how much the past anticipated our own local purposes, these stories mislead us because they are too much about us. We are not all that.

Making sense of our lives by placing them within a scientific story of how we got here, we struggle to keep in mind that every moment of life’s deep past was intricately inhabited by lives-in-progress. It is so hard to imagine all those moments in all those lives, we settle for making them redundant, folding them into formulas of lawfulness and randomness, necessity and chance.

Nature took its course, we have imagined, indifferent to our ancestors’ purposeful efforts. Exaggerating the absence of purpose in our past, we threw out the baby of responsibility with the bathwater of a punishing God. We naturalized our dominion by different means but with similar ends. Shrinking our lives into molecular algorithms, these stories have done a different kind of disservice. We are more than this.

To get a clear view of how we got here and what we are doing here, we must hold in our mind’s eye a deep past of richly engaged lives (Shryock and Smail 2011). This is no easy matter. We will have to tolerate a lot of tickling of our imaginations.

Origin myths and human nature

When we talk about the role of our ancestors’ activities, which is to say animal behavior, in how we came to be, scientific theory becomes human nature mythology. Myth not as falsehood, but as “vital ingredient of human civilization … not an idle tale, but a hard-worked active force” (Malinowski 1948: 79).

Origin myths shape the kinds of people we become, by expressing a shared sense of who we are, in the telling of how we came to be. Telling of the past, they are aimed at the future.

By tradition the factual details of myths have been cooked up, knowingly, to get the story “right” in a moral sense. Intended to be forces of history more than sources of history, origin myths function as moral rudders, not archival records.

This is why literal readings of the Bible’s Genesis story, among believers and skeptics alike, miss the point. The story’s intent being allegorical, debating its historical accuracy does more to freeze moral rudders than to move them. We sway rudders better by contesting the messages within the allegory, for example: “… thy husband … shall rule over thee” (King James Bible).

Scientists aim to get the facts right, but can avoid neither social influences on their work nor social influences of their work. “Culture seeps into science unbidden” (de Waal 2001: 46). Intended or not, scientific origin theories also carry out cultural functions as origin myths, goading and curbing our moral imaginations.

So when Richard Leakey (2010) tells us that natural laws and chance are all we need to explain life’s evolution, this is an article of faith – more curb than goad – maintained in the secular culture within and around science, not a scientific finding of fact.

Whether allegory or science, we see ourselves in origin stories, the tellings of which are moral acts of historic significance (Bock 1994).

We tell two broad kinds of origin myths, presenting open or closed images of humanity. Open stories tell us that we are by nature free and therefore obliged to commit ourselves to courses of action for which we are responsible. According to these stories, history was made in part by the wits, determination and cooperation of our ancestors. The differences we make are partly of our own doing. It is possible to fail. We can also rise to challenges. Open stories remind us that we play a part on life’s stage.

Closed origin myths tell us we are born with good or bad moral qualities in our souls, hearts, bones, or more recently, genes. The past unfolded as a sequence of events caused by prior events or higher powers. When we make a difference, it is not our doing. Inevitability makes moral failings more likely but less painful, even less noticeable. Lulling our moral imaginations, these stories place us in balcony seats watching life play out (except those telling the story).

Evolution and ethics

Open versions of scientific origin myths are at home with Gould’s maxim “Moral inquiry is our struggle, not nature’s display” (1990: 12), or Simpson’s view that “ethics cannot be independent of evolution, but neither can it be derived from evolution” (1969: 142).

Closed versions channel Ruse’s view that belief in moral principles is “a collective illusion foisted upon us by our genes” (1986: 253). By assuming that ethics can be derived from evolutionary theory, these stories degrade what they are attempting to understand.

We can expect ethics to inform our understanding of life because ethics are part of human life.

For biology to inform our ethics without degrading it, we need a view of life that is also informed by ethics. We can expect ethics to inform our understanding of life because ethics are part of human life with beginnings in mammalian life. The moral imaginations of Abraham Lincoln, Mahatma Gandhi, Martin Luther King and their contemporaries were imaginary in the sense that they were of the imagination, fantastic in the sense of extraordinary goodness, and neither in the sense of being not real (Bromwich 2014).

And what does morality tell us about how we got here? Morality indicates a deeper history of its building blocks than is usually told. A short sketch of this history goes something like this (from Rosslenbroich 2014).

Life is inherently semi-autonomous

For 3.6 billion years, life has been an emergent and open process harnessing the reliabilities of physics and chemistry, in constant tension between its self-directed inside and dependence on what is outside. Living its freedom by degrees, life is semi-autonomous.

As a fundamental characteristic of life, autonomy is a mainspring of evolution, not a residue. Biology does not merely constrain autonomy. Biology – life – sustains autonomy, as it has from its beginning.

Autonomy has evolved

Capacities for self-direction and relative independence from the immediate surroundings have increased in some lines of descent. For two billion years, cells with special parts to make and store energy, keep the inside organized, and control give-and-take with the outside (eukaryotes) have been more autonomous than cells without these parts (prokaryotes).

It took eukaryotic cells a billion years to come together into multicellular organisms, each cell losing a measure of individual autonomy to gain greater overall autonomy. Exploiting the advantages of size and specialization, multicellular life (animals more so than plants) moved vital functions like breathing, digesting and eliminating waste from their surface to their inside, thus gaining further control of give-and-take with the outside.

The story of autonomy’s evolution will continue in Part 2 of this article.

References

Bock, K. 1994. Human Nature Mythology. Chicago: University of Illinois Press.

Bromwich, D. 2014. Moral Imagination. Princeton, NJ: Princeton University Press.

De Waal, F. 2001. Without walls. New Scientist 172: 46-49.

Gould, S. J. 1990. Darwin and Paley meet the invisible hand. Natural History 99 (11): 8-12.

King James Bible Online. http://www.kingjamesbibleonline.org/Genesis-Chapter-3/

Leakey, R. E. 2010. Why Our Origins Matter. Origins ’10 public lecture series, Florida State University, April 1.

Malinowski, B. 1948. Magic, Science and Religion. Glencoe, Il: The Free Press.

Rosslenbroich, B. 2014. On the Origin of Autonomy. Cham: Springer.

Ruse, M. 1986. Taking Darwin Seriously. Oxford: Blackwell.

Shryock, A. and D. L. Smail. 2011. Deep History. Berkeley: University of California Press.

Simpson, G. G. 1969. Biology and Man. New York: Harcourt, Brace and World.


Tom Clark is a psychologist who has been interested in the role of behavior in evolution since his graduate training at the University of South Florida.


© 2015, Thomas L. Clark. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed in this article are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

Darwin’s use of “use” and “disuse” (Part 3)

Tom Clark


Please note: this commentary, recovered on 8-Jan-2017, was originally published by the author, Tom Clark, on Science Dialogues on 14-Mar-2015.


DARWIN IS CREDITED with dethroning humans from their special place between animals and angels. As Copernicus had done astronomically, so had Darwin biologically.

Feral_horses_-_Pryor_Mountain_Wild_Horse_Range_-_Montana

Pryor Mountain Wild Horse Range, Montana. http://www.blm.gov/pgdata/etc/medialib/blm/mt/blm_programs/whb.Par.0228.Image.198.149.1.gif

But Darwin achieved continuity of humans with animals as much by humanizing animals as shrinking humans. Resisting “the too-ready ascription of action to instinct” (Beer 2009: 242-255), Darwin imagined that horses “admired a wide prospect,” baboons had “capacious hearts,” earthworms made aesthetic choices, and snails showed “some degree of permanent attachment.” He did not imagine that biology could benefit, as physics had, by abandoning animism, animals being so . . . animistic.

It was the neo-Darwinian assumption that genes and environments were sufficient causes of animals’ behavior that turned natural selection from an animate doing into a physical happening. Attributing behavior to stable causes both inside (molecules) and outside (environment) turned animals into spectators, along for the ride. Their mental lives were made redundant in the British sense of unemployed. (Compare John and Gabriel Terrell’s thoughts about self-generated, stimulus-independent, internally directed thought in their March 3 post Thinking about Thinking 2. Through the Looking Glass.)

Misreading Darwin’s use of use and disuse as simply Lamarckian enabled the neo-Darwinian demotion of both humans and animals, as meaningful roles for ancestors and Gods were, like baby and bathwater, summarily thrown out.

The word purpose is singularly inapplicable to evolutionary change … If an organism is well adapted … this is not due to any purpose of its ancestors or of an outside agency, such as “Nature” or “God” … (Mayr 1961: 1504).

The purposeful activities of ancestors were not final or ultimate causes. They were some among many causes. Yet they were bundled with God’s finality and dismissed. In the last paragraph of Origin of Species (Darwin 1860: 490) between his “entangled bank” metaphor and the poetic “endless forms most beautiful,” Darwin summarized the key elements of his theory. Two have been pushed to the edges of mainstream evolutionary thought, the ultimate activities of “the Creator” and the contingent activities of ancestors—”use and disuse.”

In the margins of an article by Wallace, Darwin wrote “use of moral qualities” (Greene 1981: 102), telegraphing a view of our moral origins that insinuated these dignifying lines of descent:

  • Life is inherently autonomous.
  • Autonomy has evolved (Rosslenbroich 2014).
  • Nervous systems support flexible, adaptive responding.
  • Vertebrates specialized in intention, allowing metabolic support for increasingly larger brains (Wrangham 2009).
  • Birds and mammals made relationships vital heritable resources (Kemp 2006), expanding autonomy by cooperating in relationships of secure dependence and interdependence.
  • Humans extended these achievements with ethics (Boehm 2012) and friendship (Terrell 2015).

The twentieth century dethroning of humanity carried out in Darwin’s name clipped human dignity more than Darwin intended. The following affirmations return to the evolutionary image of ourselves buds of autonomy and responsibility that Darwin was careful to leave on our family tree.

affirmWhen we consider the evolutionary role of animal behavior—or as we also say, ancestors’ activities—scientific theory becomes human nature mythology, the telling of which must be recognized as a moral act (Bock 1994: 8). The moral significance of our origin story hits home with the realization that how we tell this story can leverage or constrain personal and collective action toward sustainability (Clark and Clark 2012), peace and justice (Chorover 1979; Oyama 2000; Novoa and Levine 2010).

The sense we make of ourselves and each other shapes who we become, including our capacities for learning, cooperation and self-regulation. “Knowing” that intelligence is fixed inhibits learning (Blackwell et al. 2007). “Knowing” that personality attributes are inherited impels hasty negative judgments of others, foreclosing opportunities for constructive encounter (Dweck 2000). “Knowing” that free will is illusory engenders cheating (Vohs and Schooler 2008) and aggression (Baumeister et al. 2009). “Knowing” that humans are selfish by nature favors policies that crowd out reciprocity and trust, inducing selfish behavior (Bowles 2008). And “knowing” that metabolism is natural while intention remains a supernatural specter (Mayr 1982) hedges responsibility for our extended metabolism—energy consumption—compromising our ability to regulate our own inventions.

Knowing there is a choice to make and it matters what we choose to do prepares us for wising up to shared responsibilities and cooperating in the good use of resources.

Biologists rightly argue that a clear understanding of our evolutionary past must inform our plans for a sustainable future (Vermeij 2010: 253). Explaining the evolution of sighted animals as a blind process blinkers our understanding of the past, so also our outlook. Envisioning and motivating sustainable living is better served by an origin story that includes the vision and intentions of ancestors.

Evolution is not only what happened to our ancestors while they were busy making other plans. Ancestors did not plan our evolution, but their plans, successful or not, with consequences intended or not, were part of the story.

In the way he used use and disuse, Darwin recognized our ancestors’ part in how we came to be and our part in resolving where we go from here. By affirming our autonomy and interdependence, Darwin’s origin story also demands of us continued use of our moral imaginations.

References

Baumeister, R. F., E. J. Masicampo, and C. N. DeWall (2009). Prosocial benefits of feeling free: disbelief in free will increases aggression and reduces helpfulness. Personality and Social Psychology Bulletin 35: 260–268.

Beer, G. (2009). Darwin’s Plots (3rd ed.). Cambridge: Cambridge University Press.

Blackwell, L. S., K. H. Trzesniewski, and C. S. Dweck (2007). Implicit theories of intelligence predict achievement across an adolescent transition: a longitudinal study and an intervention. Child Development 78: 246–263.

Bock, K. (1994). Human Nature Mythology. Urbana: University of Illinois Press.

Boehm, C. (2012). Moral Origins. New York: Basic Books.

Bowles, S. (2008). Policies designed for self-interested citizens may undermine ‘the moral sentiments’: evidence from economic experiments. Science 320: 94–112.

Chorover, S. L. (1979). From Genesis to Genocide. Cambridge: MIT Press.

Clark, T. and E. Clark (2012). Participation in evolution and sustainability. Transactions of the Institute of British Geographers 37: 563–577.

Darwin, C. R. (1860). On the Origin of Species (2d ed.). In J. van Wyhe, ed., 2002 The Complete Work of Charles Darwin Online(http://darwin-online.org.uk).

Dweck, C. S. (2000). Self Theories. Philadelphia: Psychology Press.

Greene, J. C. (1981). Science, Ideology, and World View. Berkeley: University of California Press.

Kemp, T. S. (2006). The origin of mammalian endothermy: A paradigm for the evolution of complex biological structure. Zoological Journal of the Linnean Society 147: 473–488.

Mayr E. (1961). Cause and effect in biology. Science 134, 3489: 1501–1506.

Mayr E. (1982). The Growth of Biological Thought. Cambridge: Harvard University Press.

Novoa, A. and A. Levine (2010). From Man to Ape. Chicago: University of Chicago Press.

Oyama, S. (2000). Evolution’s Eye. Durham: Duke University Press.

Rosslenbroich, B. (2014). On the Origin of Autonomy. Cham: Springer.

Terrell, J. E. (2015). A Talent for Friendship. Oxford: Oxford University Press.

Vermeij G. J. (2010). The Evolutionary World. New York: St. Martin’s Press.

Vohs, K. D. and J. W. Schooler (2008). The value of believing in free will: encouraging a belief in determinism increases cheating. Psychological Science 19: 49–54.

Wrangham, R. (2009). Catching Fire. New York: Basic Books.

Tom Clark

As a psychologist, I have been interested in the role of behavior in evolution since my graduate training at the University of South Florida.

 

 

© 2015, Thomas L. Clark. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed in this article are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

 

 


Darwin’s use of “use” and “disuse” (Part 2)

Tom Clark


Please note: this commentary, recovered on 8-Jan-2017, was originally published by the author, Tom Clark, on Science Dialogues on 7-Mar-2015.


AT CHICAGO’S CENTENNIAL CELEBRATION of Origin of Species, Julian Huxley (1960: 14) attributed to Darwin this “Lamarckian error”:

… he did believe in the inheritance of certain “acquired characters”—the effects of the conditions of life and of use and disuse.

Though Darwin had been careful to use the terms use and disusedescriptively in Origin of Species, Huxley took them as categorically Lamarckian, a separate alternative to natural selection that did not mingle with it.

Ernst Mayr also presented Darwin’s thinking about use and disuse as singularly Lamarckian, in support of which he quoted from Origin of Species (1859: 134):

There can be little doubt that use in our domestic animals strengthens and enlarges certain parts and disuse diminishes them; and that such modifications are inherited.

Underscoring his Lamarckian take on Darwin, Mayr adds (1982: 691):

Use and disuse, of course, is of importance only if one believes in an inheritance of acquired characters. This Darwin affirms repeatedly … Darwin is quite positive: “Modifications [caused by use and disuse] are inherited.”

Standing alone, the sentence Mayr quotes from Origin of Species looks like a Lamarckian match. With each step back to see it in context, the resemblance fades.

In the next sentence, Darwin (1859: 134) refers to “… the effects of long-continued use and disuse,” not one generation to the next.

In the same paragraph he places use and disuse in the situation of stable selection pressures, offering as examples the “… wingless condition of several birds, which … inhabited several oceanic islands tenanted by no beasts of prey.”

On the next page he explicitly rejects Lamarckian inheritance of mutilations.

On the following page he clarifies “long-continued,” referring to “thousands of successive generations.”

And throughout Origin of Species, Darwin uses “acquired” only in reference to species across many generations in the context of specific selection pressures, not in the Lamarckian sense of individuals transmitting from one generation to the next characteristics acquired during their lifetimes.

In context, the “domestic animals” Darwin drew to our attention were domesticated species, not his neighbor’s individual dogs. Darwin saw species acquiring traits that became heritable when long-continued activities shaped selection pressures.

Jean Gayon repeated Mayr’s Lamarckian misreading of the identical quote from Origin of Species a decade later (1998 [1992]: 150).

Gayon is in the good company of many besides Huxley and Mayr. Science educators bemoan their failure to convince students that natural selection “does not involve effort, trying, or wanting” or “organisms trying to adapt” (Understanding Evolution, 2014). When their students accurately intuit that evolution has produced animals capable of effortful adaptation and these efforts can affect selection processes, this is considered “a significant departure from a scientific understanding of how animals change via natural selection” (Kelemen 2012: 71).

Huxley, Mayr, Gayon and science teachers stumbled over that ordinary and useful habit of thought, categorizing, while overlooking Darwin’s earnest doubts about the categories of his cultural inheritance (Beer 2009: xxx). The terms use and disusegrew into their common biological usage during the Lamarckian half-century that preceded Origin of Species. While Darwin was growing up, they acquired conceptual, social and political significance beyond concrete reference to specific animal activities. For many, the terms were synonymous with Lamarckian inheritance. Lamarckism has been called use-disuse theory.

When Darwin used these terms, he knew the importance of their secondary meanings for his readers. He also recognized the scientific and public relations merits of using these familiar terms for animal behavior in a more descriptive, pared down way.

Scientifically, he advanced more modest claims of animal agency than Lamarckian use of the terms. Darwin’s descriptive use of use and disuse created conceptual space for a developmental view of evolution that was not Lamarckian.

At the same time, Darwin wanted his readers to follow his argument and not give up on it. Pushing against the constraints of traditional terms by using them in nontraditional ways, Darwin’s “generous semantic practice” (Beer 2009: 33) allowed the reader to adjust their own yoke to the terms use and disuse. From his calibrated ambiguity, readers could hear in the text such Lamarckian overtones as their sensibilities favored.

Darwin’s semantic generosity quickened after publication of Origin of Species, as he responded to waves of criticism with a strategic retreat toward inclusiveness. In Variations of Animals and Plants under Domestication (1868), “anything which had been documented and accepted by a fellow scientist was included and assessed” (Vorzimmer 1963: 386). Darwin admitted for discussion a provisional hypothesis of Lamarckian inheritance that he had carefully avoided in Origin of Species. Darlington (1959: 41) complained that during this time “ambiguity … became the mode and standard of Darwin’s expression … which in the end soothed and satisfied the troubled world.”

As he changed successive editions of Origin of Species – to his wife Emma’s delight, adding “the Creator” in the second edition – Darwin remained committed to respectful, empirical inquiry that doubled as good public relations for his theory.

Bufflehead_taking_off

Bufflehead, Morro Bay State Park CA. by Kevin Cole 2008. http://commons.wikimedia.org/wiki/File:Male_Bufflehead_taking_off.jpg

While molecules eclipsed the behavior and development of whole organisms in 20th century evolutionary thought, accounts from Darwin’s vantage point persisted. Nobel physicist Erwin Schrödinger (1944: 113) echoed Darwin most clearly.

You simply cannot possess clever hands without using them for obtaining your aims… You cannot have efficient wings without attempting to fly… Selection would be powerless in ‘producing’ a new organ if selection were not aided all along by the organism’s making appropriate use of it….

Joining Huxley at Chicago’s centennial celebration of Origin of Species, Conrad Waddington (1959: 1636) presented a model of evolution that included animal choices.

Thus the animal by its behavior contributes in a most important way to determining the nature and intensity of the selective pressures which will be exerted on it.

Half a century on, Renée Duckworth (2009: 514) marked Origin’s sesquicentennial by reminding us that:

Changes in either the environment or an organism’s behavior can alter selection pressure. This places behavioral change on an equal footing with environmental change as a potential cause of evolutionary change … but despite the intuitive appeal of this idea, it remains largely unacknowledged in current evolutionary theory.

And Mary Jane West-Eberhard (2008: 902) rendered Darwin in contemporary terminology.

Much of Darwin’s discussion of … “use and disuse” refers not to Lamarckian inheritance but to what we would now call “phenotypic plasticity” [flexibility of the whole organism].

References

Beer, G. (2009). Darwin’s Plots (3rd ed.). Cambridge: Cambridge University Press.

Darlington, C. D. (1959). Darwin’s Place in History. Oxford: Basil Blackwell.

Darwin C. (1859) On the Origin of Species. In J. van Wyhe, ed. (2002), The Complete Work of Charles Darwin Online (http://darwin-online.org.uk).

Darwin, C. (1868). Variation of Animals and Plants Under Domestication. In J. van Wyhe, ed. (2002), The Complete Work of Charles Darwin Online (http://darwin-online.org.uk).

Duckworth, R. (2009). The role of behavior in evolution: A search for mechanism. Evolutionary Ecology 23: 513–531.

Gayon, J. (1992) [1998]. Darwin’s Struggle for Survival. Cambridge: Cambridge University Press.

Huxley, J. (1960). The emergence of Darwinism. In Evolution After Darwin, vol. I: The Evolution of Life, Sol Tax, ed., pages 1–21. Chicago: University of Chicago Press.

Kelemen, D. (2012). Teleological minds: How natural intuitions about agency and purpose influence learning about evolution. In Evolution Challenges: Integrating Research and Practice in Teaching and Learning about Evolution, Rosengren, K.S., S. K. Brem, E. M. Evans, and G. M. Sinatra, eds., pages 66–92. Oxford: Oxford University Press.

Mayr E. (1982). The Growth of Biological Thought. Cambridge: Harvard University Press.

Schrödinger E. (1944). What is Life? Cambridge: Cambridge University Press.

Understanding Evolution, University of California Museum of Paleontology, 01 January 2014 http://evolution.berkeley.edu/evolibrary/misconceptions_teacherfaq.php

Vorzimmer, P. (1963). Charles Darwin and blending inheritance.  Isis 543: 371–390.

Waddington, C. 1959 Evolutionary systems – animal and human. Nature 183 4676:1634-1638.

West-Eberhard, M. J. (2008) Toward a modern revival of Darwin’s theory of evolutionary novelty. Philosophy of Science 75: 899-908.


Tom Clark

As a psychologist, I have been interested in the role of behavior in evolution since my graduate training at the University of South Florida.

 

 

© 2015, Thomas L. Clark. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed in this article are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

 


Darwin’s use of “use” and “disuse” (Part 1)

Tom Clark


Please note: this commentary, recovered on 8-Jan-2017, was originally published by the author, Tom Clark, on Science Dialogues on 28-Feb-2015.


LIKE OTHER NATURALISTS OF HIS DAY, Darwin thought that when animals used their bodies in some ways and not others, doing this and not that, these activities affected the evolution of their kind. Insect wings and rodent eyes became larger or smaller, more useful or less, depending on their ancestors’ use or disuse of their wings and eyes.

Unlike his peers, Darwin imagined animal behavior influencing evolution without Lamarckian inheritance of acquired characteristics. His most important discovery, natural selection, allowed him an alternative. Instead of direct transmission, from one generation to the next, of changes brought about by an animal’s activity within its lifetime, Darwin saw that such activity affects both how animals grow into adults—variation—and how natural selection plays out. And by way of long continued selection outcomes, characteristics expressed while growing up—specific variants—can become, somehow, more likely to develop in later generations. Hence, evolution.

Stretching to browse on trees did not cause giraffe ancestors to have offspring with longer necks. Rather, giraffe ancestors’ browsing habits swayed selection so giraffes that grew longer necks tended to have more offspring.

Giraffa_camelopardalis (5)

Photograph of Giraffa camelopardalis by Scott Harrison, Kruger Park 2006. http://commons.wikimedia.org/wiki/File:Giraffa_camelopardalis.JPG#file

Growing up mattered. Darwin observed variation among whole animals through their lifetimes, not variation among genes. Anything that made a growing child “not absolutely similar to the parent” was a source of variation that could make a difference in selection processes and outcomes (Darwin 1857). Darwin’s view was developmental, not Lamarckian.

Darwin understood that separating variation and selection was tidier in theory than in actual lives-in-progress. He took up his discussion of use and disuse in a chapter called “Laws of Variation” with a subheading “Use and disuse, combined with natural selection” (Darwin 1859: 131, italics added). What animals did with whom was a central and natural aspect of selection, as well as a source of variation. Animal behavior comprised and induced variation that was grist for selection and also part of the mill.

So he shows us in Origin of Species (1859: 136–143) that “the wings of some of the insects have been enlarged, and the wings of others have been reduced by natural selection aided by use and disuse.”

The wingless condition of so many Madeira beetles is mainly due to the action of natural selection, but combined probably with disuse.

And,

The eyes of some burrowing rodents are rudimentary in size… probably due to gradual reduction from disuse, but aided perhaps by natural selection . . . natural selection would constantly aid the effects of disuse.

So,

On the whole, I think we may conclude that habit, use, and disuse, have, in some cases, played a considerable part in the modification . . . of various organs; but that the effects of use and disuse have often been largely combined with, and sometimes overmastered by, the natural selection of innate differences.

Animals were protagonists in Darwin’s evolutionary plots. Theirs was an unwitting participation, animal intentions being of evolution, not about evolution. Still, animals’ semi-autonomous activities affected the evolution of their own kind and of others who came to their attention. Darwin saw, for example, that arbitrary “aesthetic” preferences of pollinating insects—going to these flowers more than those—affected selection of the flowers and of the insect’s nose, used to reach that flower’s nectar.

Darwin concerned himself with mechanisms of biological inheritance but had limited evidence to go on. Mendel published his experiments on plant hybridization in 1865 but with just three citations in 35 years, they never came to Darwin’s attention. Though he eventually proposed a Lamarckian mechanism of inheritance in his “provisional” hypothesis of pangenesis, Darwin continued to view the role of animal behavior in evolution as more developmental than Lamarckian. Animal activity naturally “either checked or favored” selection (1868: 234).

His developmental view of evolution endured August Weismann discerning a “barrier” between somatic and germ cells. Weismann’s famous barrier, allowing transmission of only germ cells to the next generation, was the death knell for Lamarckism. Yet Weismann affirmed Darwin’s view that “use and disuse” affected evolution by way of natural selection.

Weismann contrasted “mere disuse” with its consequence that “natural selection ceases to act” (1889: 15–16). By this relaxation of selection, disuse induced evolutionary change. Regarding use,

. . .  the direct influence of increased use during the course of a single life [cannot] produce hereditary effects without the assistance of natural selection (1889: 91).

And with the assistance of natural selection, it can.

. . . the use and disuse of parts can have no direct share in the process. . . . The fact, however, that we deny the transmission of the effects of use and disuse, does not imply that these factors are of no importance. . . . both use and disuse may lead indirectly to variations . . .  [that change selection processes and outcomes] (Weismann 1893: 395–396).

Darwin’s developmental view fell to the margins of evolutionary thought with the rediscovery of Mendel’s experiments that began the 20th century and initiated its turn toward a molecular gaze. In an historic cultural shift dubbed “bath-waterism” (Ewer 1960: 162), evolutionary thought threw out, along with the bath water of Lamarckism, the whole organism as an agent of evolutionary change. Evolutionary science transformed our image of ourselves from protagonists in the story of life to products of natural laws and chance, from the result of ancestors’ doings to the result of chemical happenings.

Our story changed from processes of selection that naturally had the benefit of vision and other senses and capabilities for the past 600 million years to “blind” selection the whole way; from an understanding that manners maketh the man, and action maketh the organism, to an understanding that tiny entities inside us make us who we are; from a story at the scale of organisms and lifetimes to a story about molecules across eons; from a story that includes growing up to a story that moves from one adult generation to the next by incantations of genes, environments and their so-called “interactions” (genes, of course, interact only with intra-cellular environments); from plot without humans to humans without plot; from a story teeming with human agency and meaning to a story of eggs regarding chickens as merely a way to make more eggs; from a story that tells us of life’s expanding autonomy, so what we do matters, to a story that tells us choice is a comforting illusion so we have no say in the course nature takes.

Among the ideas slanting these images of ourselves has been a misreading of Darwin’s use of use and disuse as simply Lamarckian.

References

Darwin, C. (1857). Letter to Asa Gray, 5 Sept. http://www.darwinproject.ac.uk/entry-2136.

Darwin C. (1859). On the Origin of Species. In J. van Wyhe, ed., (2002), The Complete Work of Charles Darwin Online (http://darwin-online.org.uk).

Darwin, C. (1868). Variation of Animals and Plants under Domestication. In J. van Wyhe, ed., (2002), The Complete Work of Charles Darwin Online (http://darwin-online.org.uk).

Ewer, R. F. 1960 Natural selection and neoteny. Acta Biotheoretica13:161-184.

Weismann, A. (1889). Essays Upon Heredity. Oxford: Clarendon Press.

Weismann, A. (1893). The Germ Plasm. New York: Scribner.


Tom Clark

As a psychologist, I have been interested in the role of behavior in evolution since my graduate training at the University of South Florida.

 

 

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