Tuesday, March 28, 2017

Thinking About Galapagos (10): Finding God in Galapagos

        The Charles Darwin Mural on Charles Darwin Avenue in Puerto Ayora, Santa Cruz Island

On the last day of our tour, the Cormorant was anchored in Academy Bay, the harbor of Puerto Ayora on Santa Cruz Island.  In the morning, we went to see the giant tortoise breeding facility at the Charles Darwin Research Station on the eastern end of Charles Darwin Avenue.  On our way there, we walked past the mural pictured above.  Darwin's head floats over the Galapagos, as if he has taken the place of God. 

This could be seen as suggesting something like the "religion without revelation" proposed by Julian Huxley, in which the Darwinian story of evolution replaces the biblical story of Creation.  In fact, Huxley was one of the leaders of the "Galapagos International Scientific Project" for establishing the Charles Darwin Research Station and for making Galapagos an Ecuadorian National Park that would attract ecotourists from around the world.  Part of this project was to have the tourists guided by naturalist guides trained in evolutionary science who would teach the tourists to see Galapagos as providing them the conclusive evidence for the Darwinian story of how all life evolved on Earth as a substitute for the biblical story of how "in the beginning, God created the heavens and the earth.".  In 1966, Huxley wrote: "It was on the Galapagos . . . that Darwin took the first step out of the fairyland of creationism into the coherent and comprehensible world of modern biology."

At the western end of Charles Darwin Avenue, one can find Loma Linda Academy, a private school operated by the Seventh Day Adventist Church.  The school has a mural showing the animals of Galapagos looking up at the sky.  The writing on the mural declares: Todo la creacion exalta al creador.  "All creation exalts the Creator."  So it seems that some people in Galapagos are still living in "the fairyland of creationism." 

It is not surprising that a Seventh Day Adventist school should be teaching creationism as an alternative to Darwinism.  The modern creationist movement has been led by Seventh Day Adventists influenced by the teachings of Ellen White (1827-1915), the charismatic prophet who founded their church.  The Adventists emphasized the importance of observing the Sabbath on Saturday as a memorial to the six days of Creation.  God had commanded the keeping of the Sabbath, "for in six days the Lord made heaven and earth, the sea, and all that in them is, and rested the seventh day: wherefore the Lord blessed the Sabbath day, and hallowed it" (Exodous 20:11). Consequently, White and the Adventists opposed any scientific claim that the days of creation should be interpreted symbolically, or as something other than a literal six twenty-four hour days.  In 1864, White confirmed this teaching by reporting her divine vision in which she was "carried back to the creation and was shown that the first week, in which God performed the work of creation in six days and rested on the seventh day, was just like every other week."

White also interpreted the Genesis account of Noah's flood as a worldwide catastrophe that created the geological strata and fossils that we see today.  This refuted the geologists who saw the geological record as showing the Earth to be at least hundreds of millions of years old. 

The best history of creationism--Ronald Numbers, The Creationists: From Scientific Creationism to Intelligent Design (Harvard University Press, 2006)--emphasizes the influence of Seventh Day Adventist theology on creationism.  This tradition of Adventist creationist attacks on evolution continues in the presidential administration of Donald Trump: Ben Carson, the Secretary of Housing and Urban Development, is a Seventh Day Adventist who has regularly lectured on the falsity of evolutionary science.

Beginning in 1902, Adventist George McCready Price (1870-1963) wrote a series of books arguing that the evidence of geology and biology supported White's interpretation of biblical creationism and refuted Darwinian evolutionary science.  Nevertheless, Price sometimes conceded a lot to the Darwinian theory of the evolution of species.  In the first chapter of Genesis, God is said to have created the "kinds" of plants and animals.  "Kind" is the King James English translation of the Hebrew word min, which is as vague as the English word.  If "kind" means "species," then one would have to say that God originally created all species of plants and animals as fixed, and therefore there can be no evolution of new species.  This was the "theory of special creation" that Darwin challenged in The Origin of Species with his "theory of natural selection."  Sometimes, however, Price identified the created "kinds" as "the great stocks, or families" created by God, which allowed for natural variation within these created kinds that could cause the evolution of new species, and this would support Darwin's position, at least within some broad limits.

This point was made clear by Frank Lewis Marsh, an Adventist scientist and follower of Marsh.  Marsh received his Ph.D. in botany from the University of Nebraska in 1940, which made him the first Adventist with a doctoral degree in biology.  Marsh began to doubt the idea that all species had originated by separate acts of divine creation at the beginning.  It was hard to see how Adam could have named all the species of birds and land animals in one day (Genesis 2:19-20).  It was also hard to see how Noah's Ark was large enough to hold two of each species of birds and land animals (Genesis 6:19-20).

The solution to these and other problems was to identify created "kinds" as belonging to some taxonomic rank higher than "species," and thus one could allow for the Darwinian evolution of species within the limits of each "kind."  Marsh coined the term "baramin"--from the Hebrew words bara ("created") and min ("kind")--to denote the original units of creation, the created kinds.  Later, creationist Kurt Wise coined the term "baraminology" for the scientific identification and study of created kinds; and creationist Todd Wood has employed some statistical techniques for identifying baramins, which he has applied to the study of Galapagos (Wood, A Creationist Review and Preliminary Analysis of the History, Geology, Climate, and Biology of the Galapagos Islands [Eugene, OR: Wipf and Stock Publishers, 2005]).  So, unlike the "theory of special creation" refuted by Darwin, which assumed the fixity of species originally created by God, modern creationism has accepted a limited evolution of species within created kinds (see Todd Wood, "Species Variability and Creationism," Origins, number 62 [2008]: 6-25). 

Indeed, all creationists accept evolution to some extent.  The question is where to set the boundaries beyond which evolution cannot go.  This is the question posed by the evidence of Galapagos: Is this evidence of evolution, but only within certain limits?

This was the kind of question that Marsh raised in his extensive correspondence with Theodosius Dobzhansky, one of the leading proponents of the "modern synthesis" of evolutionary theory.  In Genetics and the Origin of Species (Columbia University Press, 1937), Dobzhansky had distinguished "microevolution" and "macroevolution."  Microevolution is evolutionary change that we can observe during a human lifetime.  Macroevolution is evolutionary change that occurs over long geological periods, and thus we cannot directly observe it, but we might infer it from our study of the fossil record and of the present distribution of species.

For Marsh, all of the directly observable evidence for evolution was evidence of microevolution of species within created kinds (baramins).  There was no directly observable evidence for the macroevolution of new kinds of plants and animals from earlier forms of life, Marsh argued.  When Dobzhansky responded by arguing that such macroevolution occurred only over long geological time, and thus it could "be proven or disproven only by inference from the available evidence," Marsh complained: "Alas! Inferential evidence again!  Is there no real proof for this theory of evolution which we may grasp in our hands?"  Dobzhansky answered with frustration: "If you demand that biologists would demonstrate the origin of a horse from a mouse in the laboratory, then you just can not be convinced."

Marsh rejected the inferential evidence for macroevolution because it contradicted what Marsh interpreted as the biblical history of creation as the truth of divine revelation.  That biblical truth should be taken seriously by scientists.  Although Dobzhansky was not persuaded by this, he accepted this as an honest statement of Marsh's faith that "the account given by the Bible is settled for you before you begin to consider the biological evidence."

What we see here are the two interrelated fundamental dichotomies employed in modern creationist argumentation over evolution: microevolution versus macroevolution and observational science versus historical science.  Observational science is based on what we can know by direct observation or experimentation.  Historical science is based on inferences about what has happened in the distant past that we cannot directly observe or experimentally test.  The inferences of historical science depend upon our fundamental assumptions about the universe--our worldviews. 

So if we have a biblical worldview that assumes the literal truth of the Bible, we will infer that while there has been microevolution within created kinds, there has been no macroevolution of kinds.  But if we have a secularist worldview that denies the truth of the Bible, then we might infer that all the kinds of plants and animals have evolved by purely natural processes from common ancestors, and perhaps ultimately from one primitive form of life.  Both of these worldviews rest on faith, the creationists argue, because even the secularist worldview rests on a kind of faith that the entire past history of the universe has been governed by purely natural laws without any miraculous interventions by God, although it's impossible for us to confirm this assumption by direct observation of the past. 

I suspect that this creationist use of the term "worldview" comes from David Noebel's Understanding the Times: The Religious Worldviews of Our Day and the Search for Truth (Eugene, OR: Harvest House Publishers, 1991).  For over 40 years, Noebel has conducted two-week seminars for high school students teaching them how to defend a biblical "worldview" against alternative "worldviews"--such as secular humanism and Marxism--and a creationist rejection of Darwinian science is a crucial part of that biblical worldview.  I first heard Noebel talk about this in 1961, when I was a high school student in one of his seminars at The Summit in Manitou Springs, Colorado.

Another possible source for the "worldview" idea is Thomas Kuhn's account of science as based on "paradigms" that constitute fundamental assumptions about the universe that cannot be proven empirically but which organize scientific thinking and research.  Creationists can argue that every scientific paradigm is a kind of faith commitment, and thus creationism can be a paradigm for science.

Although we cannot prove that either of these worldviews is true, we can debate whether one or the other provides the most plausible explanation for the world of observational experience.  So, for example, those of us with a secularist worldview will tour the Galapagos and see it though the lens of that worldview, while those of us with a biblical worldview will tour the Galapagos and see it through that very different biblical lens.  We will see the same geological and biological phenomena, but we will draw different inferences about the ultimate causes of those phenomena.  We can then debate with one another about which explanatory inferences are most plausible.

As I have indicated in my previous posts, the naturalist guides in Galapagos have been trained in the secularist worldview of Darwinian science, and so they teach the tourists to see Galapagos through that lens; and the people on my two tours were receptive to that teaching.  But I know that there have been creationists who have toured the Galapagos, and who have seen it as providing confirmation of God's creative activity. 

Any visitors within the protected area of the Galapagos National Park must be accompanied by a naturalist guide trained and authorized by the Galapagos National Park Directorate, and these guides always assume the truth of the Darwinian worldview.  But creationist visitors can apply their own creationist views, and they can bring with them creationist teachers to give them lectures that contradict what the naturalist guide is saying.

Beginning in the early 1970s, shortly after commercial airline service to Galapagos was started, Lester Harris, a Seventh Day Adventist creationist in the biology department of Loma Linda University, began to lead regular summer tours of Galapagos for his students.  He also assisted in the buying of the property in Puerto Ayora for establishing Loma Linda Academy.  He wrote the first creationist book on the Galapagos--Galapagos: A Creationist Visits Darwin's Islands (Nashville, TN: Southern Publishing Association, 1976).

Harris's book is a charming set of stories about his observations of the flora and fauna of Galapagos.  But the general theme running through those stories--usually stated at the end of each chapter--is that while Darwin drew some correct conclusions from what he saw in Galapagos, he jumped to bigger conclusions than he should have when he denied that there was any evidence for biblical creationism.  Darwin correctly saw evidence for microevolution in Galapagos, Harris argued, but Darwin mistakenly inferred that this showed a macroevolution of all life by natural processes that did not require any divine creation.

Without citing any of the creationist authors like Price and Marsh who argued for the limited evolution of species within divinely created kinds, Harris employed their reasoning.  For example, in his chapter on Darwin's finches, he wrote:
"It was only after returning to England following his famous round-the-world voyage on the H.M.S. Beagle that Darwin had time t analyze his collection of the birds that now bear his name.  They seemed to him to offer evidence that disproved the separate creation of animal species.  He reasoned that if the special-creation theory is true, then it was a strange coincidence of creation to find thirteen similar species of finches existing only in the Galapagos Islands."
"He was right.  At that time many people believed that God had created each new species right where man found it. Darwin couldn't accept that idea.  From his study of the finches, giant tortoises, and other animals in the Galapagos Islands, he developed the idea that each new species found only there had developed from some ancestor that came out from the mainland soon after the formation of the island."
"Darwin reasoned that newly arrived finches would be able to change to fit the particular circumstances of each island.  Later the new species would spread to the nearest neighbor islands, and then several species would be able to live in harmony since they had developed different-type beaks to fit their various feeding habits."
"Today we accept Darwin's conclusion about the finches' immediate origin, but we can't agree with Darwin when he proposes that both finches and marine iguanas had the same ancestor at some time in the distant past.  Each originated from its own creature type.  The evidence of change in both is real, but the degree of change is a theoretical point of argument" (118-119).
So Darwin was right to deny the theory of special creation that would assert that the species endemic to Galapagos were specially created by God for Galapagos.  But he was wrong not to see that the evolution of new species in Galapagos was possible because God had originally created all the basic kinds of plants and animals so that they had within them (in their genetic endowment) the capacity for adaptive change to fit the unique circumstances of Galapagos.

We can see God in Galapagos because we can see that the evolutionary adaptations of new endemic species there manifest the potentialities that God built into His original created kinds.

Since Harris's tours, other creationists on tours of Galapagos sponsored by the Institute for Creation Research, Ken Ham's Answers in Genesis, and other creationist groups have reached the same conclusions as Harris.

In my next post, I will continue my analysis of the creationist interpretations of Galapagos.

Monday, March 20, 2017

Thinking About Galapagos (9): Darwin's Snails

If I had had the opportunity to hike the highlands of Floreana, I would have looked for land snails, which are said to be abundant there in some spots.  There are seventy species of Bulimulus land snails that are endemic to Galapagos.  The stunning variation in these species both between the islands and within each island make them one of the best examples in the world of adaptive radiation.

                                                           Galapagos Land Snails
               Examples of the Variety of Land Snail Shells, the Top Four are from Galapagos

Two of the leading scientists studying the bulimulid land snails in Galapagos--Christine Parent and Guy Coppois--have written a article surveying their studies.  Parent's dissertation--"Diversification on Islands: Bulimulid Land Snails of Galapagos" (2008)--is available online. 

What I find most fascinating about this is how speciation can create diverse adaptations for extremely small microhabitats, so that these snail species fill distinct and very narrow ecological niches within the islands.  Unfortunately, the disturbance of these microhabitats from human beings--as, for example, the growing human population on Santa Cruz Island--has led to the extinction of many species.  There is some evidence that two-thirds of the seventy species of Galapagos land snails cannot be found today.

Darwin collected as many as 15 species of bulimulid land snails endemic to Galapagos.  Such adaptive radiation in the islands raised at least two kinds of questions for him.  First, how did the ancestors of these snails reach the islands?  Since land snails are easily killed by salt, it's hard to see how they could have floated across hundreds of miles of sea.  At his home in Down, as reported in Origin of Species, Darwin experimented with putting snail eggs in salt water, and he found that they sunk and died.  But then it occurred to him that when hibernating, land snails seal up their shells to prevent desiccation.  He found that these sealed shells could be immersed in salt water for up to 20 days, and they survived.  He speculated that sealed shells could be floated in chinks of drifted timber across hundreds of miles of ocean.

He also considered the possibility that land snails could have travelled to remote islands on the feet of birds.  He suspended a duck's feet in an aquarium where eggs of fresh-water snails were hatching, and he found that the shells would attach to the duck's feet, and they would survive for up to 20 hours, which might be enough time for the birds to fly hundreds of miles across the sea.  More recently, some scientists have found that birds can be fed land snails, and some of the snails can survive when they come out the other end of the bird (Shinichiro Wada, "Snails Can Survive Passage Through a Bird's Digestive System," Journal of Biogeography 39 [2012]: 69-73).  This illustrates how evolutionary theory is open to experimentation.

The second question about the adaptive radiation of land snails is how exactly does evolution by natural selection explain this?  A general principle that applies here is divergence.  Darwin saw that within species, the competition for resources tends to favor forms that "become adapted to many and highly diversified places in the economy of nature" (Autobiography, 1959, 121).  That this has happened with the Galapagos land snails is supported by the evident gathered by Parent that the richest of species is positively correlated with habitat diversity.  The largest, oldest, and highest islands have the greatest diversity of niches, and they have also had the largest number of bulimulid land snail species.

One factor in this adaptive radiation is the need for land snails to avoid dehydration.  At the highest altitudes, there is plenty of moisture.  At the lowest altitudes, the conditions are arid.  One can see this clearly by travelling across Santa Cruz Island.  As one ascends from the lower arid coastline, one climbs to higher elevations that are much wetter, and the vegetation becomes lush.  At the highest altitudes, the rounded shell of a land snail has relatively large shell opening, and this works because there is plenty of moisture.  But at the lowest altitudes, such a shell creates a risk of dehydration and death; while a pointier shell with a relatively small opening is less likely to dehydrate.  Shells are under genetic control, so those individual snails with shells adapted to their environment will tend to survive, while those with shells not so well adapted are less likely to survive.  Here, then, is natural selection at work.

This supports what Darwin called his "theory of natural selection" as superior to what he called the "theory of special creation"--the idea that each species had to be separately created by a miraculous act of God.  And, indeed, Henry Nicholls, in his book The Galapagos: A Natural History, concludes his section on the evolution of the Galapagos land snails by declaring: "The hardy survivors will have been naturally selected, not by some forethinking, supernatural selector, but by virtue of the simple fact that they didn't die" (67).

But while some creationist scientists do believe that God must create each species separately, others interpret the Biblical doctrine of divinely created "kinds" as suggesting that "kinds" correspond to large taxonomic groups of organisms--perhaps "families"--within which species evolve by natural selection.  So while "kinds" are divinely fixed, "species" are not.  Creationists who take this position can accept the evidence for evolution in Galapagos as compatible with their belief that God is the ultimate Creator of life.  Those scientists today who scorn scientific creationism rarely consider this form of creationism. 

I will take up this issue in my next post--on "Finding God in Galapagos."

Sunday, March 19, 2017

Thinking About Galapagos (8): Darwin's Mockingbirds

In the afternoon of Day 6, our tour group went snorkeling in Gardner Bay of Espanola.  My wife and I, however, stayed on the boat to recover from our overexposure to the heat and the equatorial sun over the previous two days.  This was the hot season of the year for Galapagos, and we had seen iguanas seeking shaded protection from the midday sun and blue-footed boobies shading their eggs from the sun.  Now we were being reminded that human beings also need protection from excessive heat and sun.  We had been wearing short-sleeve shirts and shorts.  But we noted that the naturalist guides wore clothing that covered every part of their bodies, even gloves and bandanas covering their faces..

Overnight, the Cormorant sailed to Floreana Island.  On Day 7 (February 3), in the morning, we went to Champion Island, a small island (only about 23 acres) off the northeastern coast of Floreana, where we snorkeled.  I was hoping to see the Floreana Mockingbird, but unfortunately I did not.

Champion Island

Here are pictures of the four species of mockingbirds endemic to Galapagos.

                                                         The Floreana Mockingbird

                                                       The San Cristobal Mockingbird

                                                            The Espanola Mockingbird

The Galapagos Mockingbird

The drawing at the top of the Floreana Mockingbird (Mimus trifasciatus) is from John Gould's section on birds in The Zoology of the Voyage of H. M. S. Beagle, edited by Charles Darwin (London: Smith, Elder and Co., 1838-1843), page 62.  Gould was the taxonomist and ornithologist who agreed to examine all of the bird specimens that Darwin brought back to London from his trip.  Gould identified the Floreana Mockingbird as a new species endemic to Galapagos.  He also identified the finches as endemic to Galapagos, and he suspected that they differed across the islands.  The second picture is a photograph of a Floreana Mockingbird on Champion Island.  With a pale patch behind its eye and three white bands on its wing covets, the Floreana Mockingbird differs from mockingbirds on other islands.

Today, the Floreana Mockingbird is identified as one of four species endemic to Galapagos (Arbogast et al. 2006).  The other three are the San Cristobal Mockingbird (Mimus melanotis), the Espanola Mockingbird (Mimus macdonaldi) , and the Galapagos Mockingbird (Mimus parvulus).  Darwin did not land on Espanola Island, so he did not see or collect the Espanola Mockingbird.  But he did see and collect the other three species.

There are, perhaps, no more than 50 Floreana Mockingbirds left on Champion Island, and maybe a few hundred on Gardner Island, another small island off the east coast of Floreana.  On Floreana Island itself, these birds were driven to extinction by 1875 by the introduction of rat, cat, and dog predators and by the deforestation of the island's Opuntia cactus forests by feral goats and donkeys.

These Galapagos mockingbirds were an important influence on Darwin's thinking about evolution, far more important than the Galapagos finches.  While we often speak about "Darwin's finches," we might more rightly speak about "Darwin's mockingbirds" (see Arbogast et al. 2006; Grant, Curry, and Grant 2000; Grant and Estes 2009, 111-143).

This story begins with Darwin's visit to Floreana Island (then called Charles Island).  On September 24, 1835, the Beagle sailed into Post Office Bay.  We sailed into that Bay on the afternoon of Day 7.  It's called Post Office Bay because there's a wooden box behind the beach where people could drop mail.  Inbound whalers could deposit mail, while outbound whalers could pick up letters to take back home.  Even today, tourists drop off postcards for other tourists to pick up and deliver back to their countries.  Although this is a very slow postal system, it's a reminder of how important global postal systems have been for international commerce and science.  Darwin was able to send specimens and information back to England for study by English scientists.  Later, spending the greater part of his life in his house in Down, England, he was able to communicate with people around the world through the postal system, gathering information and ideas for his research.

When Darwin landed at Post Office Bay, he met Nicholas Lawson, who was the acting governor of the Ecuadorian colonists on the island.  In 1830, Ecuador had claimed the Galapagos Islands.  In 1832, the first permanent human settlement in Galapagos was established in the highlands of Floreana Island.  Most of the settlers were political prisoners expelled from mainland Ecuador.  The highlands had the wet and temperate climate and the fertile soil necessary for human agricultural cultivation, although this agricultural settlement never advanced much beyond subsistence living.  This also brought the invasive species of domesticated plants and animals that could drive endemic species to extinction.

Today, there are about 100 people living on Floreana, in the coastal town of Puerto Velasco Ibarra at Black Beach.  My biggest disappointment during our tour was that we did not sail to this town or travel up into the highlands of the island.

Lawson invited Fitzroy and Darwin to dine with him at the settlement in the highlands the next day--September 25.  Thalia Grant and Greg Estes have said that this day was "one of the most significant days of Darwin's visit to Galapagos and, indeed, of the entire voyage of the Beagle" (114).  There are two reasons for this.  First, Lawson had been exploring all the Galapagos Islands for five years, and he imparted much of what he had learned to Darwin--including the observation that the giant tortoises were so different in the different islands, that people familiar with them could identify which island a tortoise belonged to by the form of its body and its shell.  Later, Darwin said that Lawson was the first person to suggest to him that the different islands might have different species distinct to each island.  In his Voyage of the Beagle, he identified this as "the most remarkable feature in the natural history of this archipelago."

The second reason why this dinner with Lawson was so important is that Darwin saw the Floreana Mockingbird for the first time, which playfully flew to their dinner table.  He recognized that this was different from the mockingbirds he had seen on San Cristobal.  He began to collect mockingbird specimens on all four of the islands that he visited.  He did not intentionally collect an island series for any other organism.  Later, writing in his ornithological notebook, about nine months after leaving Galapagos, Darwin saw that if there were different species of mockingbirds for the different islands, and if this were also true for the giant tortoises, as Lawson had told him, this would "undermine the stability of Species."  In The Origin of Species, published 24 years after his visit to Galapagos, the mockingbirds were the only organisms from Galapagos that he mentioned as showing how natural selection could explain the geographic distribution of species in oceanic islands.

While Darwin thought that the closest living relatives of the Galapagos mockingbirds were species found in Chile and mainland Ecuador, the evidence of modern genetics suggests that the closest living relatives are mockingbirds found in the northern Caribbean islands.  It is now thought that mockingbirds first arrived in Galapagos from the Caribbean Islands between 1.6 and 5.5 million years ago (Arbogast et al. 2006).

In a series of articles written in the early 1980s, Frank Sulloway demonstrated through meticulous research that the Galapagos mockingbirds were far more important in influencing Darwin's thought than were the Galapagos finches (Sulloway 1982a, 1982b, 1983, 1984).  In March of 1837, five months after returning to England, Darwin met with John Gould, who had been examining Darwin's collections from his trip on the Beagle.  Gould identified the mockingbird specimens as three different species, each limited to a specific island.  In his diary, Darwin noted that this was the first time that he began to think that he had found evidence of "transmutation," the transformation of one species into another.

During his voyage, Darwin accepted the claim of the British natural theologians that all species were fixed and created to be perfectly suited to their environments, and that species originated either by being created in their present habitat or by dispersal from various "centers of creation."  It followed from this that endemic species would be found only in unique environments, and similar species would only be found in similar environments.  The Galapagos mockingbirds contradicted this thinking, because the different Galapagos species were endemic to different islands and yet quite similar to mockingbirds on the South American mainland.  This suggested that the endemic Galapagos species had originated from the transmutation of South American species that had migrated to Galapagos.

But while this gave Darwin the idea of natural transmutation of species, it did not give him any idea about the mechanism by which this could have happened.  That second idea came to him in the fall of 1838, when he happened to read Robert Malthus.  It struck him that with a "struggle for existence," "favorable variations would tend to be preserved, and unfavorable ones to be destroyed.  The result of this would be the formation of new species.  Here, then, I had at last got a theory by which to work" (Autobiography, 1959, 120).  For the first time, he had the theory of natural selection.


Arbogast, Brian, Sergei Drovetski, Robert Curry, Peter Boag, Gilles Seutin, Peter Grant, B. Rosemary Grant, and David Anderson. 2006. "The Origin and Diversification of Galapagos Mockingbirds." Evolution 60 (2): 370-382.

Grant, K. Thalia, and Gregory B. Estes. 2009. Darwin in Galapagos: Footsteps to a New World. Princeton, NJ: Princeton University Press.

Grant, Peter, Robert Curry, and B. Rosemary Grant. 2000. "A Remnant Population of the Floreana Mockingbird on Champion Island, Galapagos." Biological Conservation 92: 285-290.

Sulloway, Frank. 1982a. "Darwin and His Finches: The Evolution of a Legend." Journal of the History of Biology 15: 1-53.

Sulloway, Frank. 1982b. "Darwin's Conversion: The Beagle Voyage and Its Aftermath." Journal of the History of Biology 15: 325-396.

Sulloway, Frank. 1983. "The Legend of Darwin's Finches." Nature 303: 372.

Sulloway, Frank. 1984. "Darwin and the Galapagos." Biological Journal of the Linnean Society 21: 29-59.

Thursday, March 16, 2017

Thinking About Galapagos (7): The Natural and Sexual Selection of Marine Iguanas

On the morning of Day 5 (February 1), we were anchored in the harbor of Puerto Banquerizo Moreno, on the island of San Cristobal.  We took a bus to the highlands of the island where we toured the Tortoise Breeding Center.  Here tortoises are breed until they are old enough that they are not vulnerable to predation by rats.  They are returned to the exact area from which their species or subspecies came.  On my first trip to Galapagos, I toured the breeding station on Isabela.  These breeding stations are open to tourists, so that they can see giant tortoises in captivity, when they are hard to see in the wild.  I have noticed that in the scheduling of Galapagos tours, guides make sure that tourists have at least one opportunity to see giant tortoises, because these are the most charismatic animals in Galapagos, and so every tourist wants to return home with some story about seeing them.

In the afternoon, we sadly said goodbye to three of our fellow passengers, including the newlyweds, who had finished their five-day trip on the Cormorant.  We met four new passengers joining us for a four-day tour of the islands of San Cristobal, Espanola, Floreana, and Santa Cruz.

The Cormorant sailed to Kicker Rock, where we tried to snorkel.  But the water was too rough and cloudy.  Overnight, we sailed to the island of Espanola.

Suarez Point, Espanola

On Day 6 (February 2), we hiked over the rugged terrain of Suarez Point on Espanola, which is the most southeastern of the islands.  It is one of the oldest islands, and it shows less of the volcanic features evident in the other islands.  The whole of its south coast is a cliff that makes a good nesting site for the endemic Waved Albatross.  Indeed, this is the only place in the islands where the Waved Albatross can be seen.


We did not see the Waved Albatross, because they do not return to their breeding grounds on Suarez Point until mid-March.  They engage in an elaborate courtship dance and mate monogamously for life, although there is a high rate of extra-pair copulation (Jouventin et al. 2007).  They lay one egg each breeding season.  Both male and female care for the offspring until the fledgling is mature by December.  The updraft at the Espanola cliff caused by the South-East Trade Winds enables them to take off with ease, although this is a bird that is famous for its comic awkwardness in taking off, but they are elegant fliers, once they are air-born, with wing-spans of up to seven feet.

The Galapagos Marine Iguana is endemic to Galapagos, and it is the world's only sea-going lizard.  They are found on all the islands, but the seven races or subspecies vary greatly in size and color from island to island.  The males are larger and more colorful than the females.  The males are generally black or dark grey, but they take on a red or red-green color during the mating season.  The Espanola race is the most colorful of all.

                      The Brightly Colored Male of the Espanola Race of Marine Iguanas

The survival and reproduction of marine iguanas are quite an achievement that depends on many complex factors affecting mating and foraging as shaped by both natural selection and sexual selection, often in conflict.  Our naturalist guide--Xavier--explained much of this to us, showing his training in Darwinian evolutionary theory as applied to the endemic species of Galapagos.  I  questioned Xavier about this, and he spoke about how every year the naturalist guides must have a "refresher course" to learn about the latest Darwinian research on the life forms on the Galapagos.

The colors in the male begin to brighten at the beginning of the breeding season and then fade at the end of the season.  The females are looking for the best-looking males, and the good looks, Xavier explained, have been shown by scientists to be signs of vigor and good health.  Similarly, Xavier observed, human females might choose the males who are best looking, and who have the high status jobs and the biggest bank accounts.  Although he said this in a joking manner, he clearly meant it to be taken seriously, suggesting that human mating shows some of the same evolutionary logic of sexual selection as is shown in these animals.

Marine iguanas show a lek polygynous mating system (Alcock 2013, 247-54; Hayes et al. 2004).  In such a mating system, males do not search for mates, nor do they defend groups of females, nor do they defend resources that attract females.  Instead, the males gather at a traditional display ground, or lek, within which each male stakes out a territory, with the more dominant males having territories at the center of the lek.  Females come to the lek to choose the males they find most attractive.  Males at the center of the lek tend to mate with more females than do males on the periphery of the lek. This is an example of what Darwin called sexual selection through female choice, which selects for males that have the traits desired by females.  There can be a conflict between sexual selection and natural selection, in that the male traits selected by female choice can conflict with the male traits favored by natural selection, which seems to be true for marine iguanas.

In one study of 213 lekking male marine iguanas on the islet of Caamano off the southern coast of Santa Cruz Island, mating success was correlated with many different male traits (Hayes et al. 2004).  Larger males with ornamentation and free of ectoparasites were likely to have the greatest mating success.  Only the largest males in good condition become lekking males. Satellite males of intermediate size roam around the lek, but without being able to claim territories for themselves, and they seek to court and copulate with females outside the territories.  Sneaker males of small size try to quickly copulate with females before being disrupted by territorial males.  The sneaker males use sperm generated by precopulatory masturbation and stored in pouches so that they can quickly inseminate females.  Both satellite and sneaker males appear to use force to compel copulations.

This sexual selection for mating competes with natural selection for foraging (Vitousek et al. 2007).  During his time in Galapagos, Darwin was intrigued by the foraging behavior of the marine iguana.  He cut open the stomachs of several of them, and found them full of minced seaweed of a bright green or dull red color (Darwin 2004, 344-45).  He had not seen much of this seaweed on tidal rocks, so he inferred that the iguanas must be feeding off this seaweed at the bottom of the sea, at some distance from the coast.  But since the marine iguanas seemed so well adapted for swimming, he was surprised that when frightened, they would not enter the water.  Darwin threw one several times into a deep pool, but each time the iguana quickly returned to land.  He thought this apparently stupid behavior could be explained by the fact that iguanas could be preyed upon by sharks, and so the iguanas had an instinctive propensity to swim to shore as a place of safety.

Later observational studies have shown that Darwin was partly right and partly wrong.  He was partly right about the diet of marine iguanas, in that they feed primarily on two species of red alga and one species of green alga, although the preferred algal species varies among the islands.  He was partly wrong, however, in that only about 5% of marine iguanas forage subtidally by diving beneath the sea to feed on algal beds on the sea floor.  Most of the animals forage intertidally by grazing on algae exposed at low tide.  The larger iguanas tend to forage subtidally, because diving requires the strength of a larger body size, and because larger bodies require the increased nutrition from dense subtidal algal beds.  Most females and smaller males forage intertidally.  Some intermediate-sized iguanas might employ both foraging strategies.

The foraging of marine iguanas is constrained both temporally and spatially.  Intertidal foraging is limited to the period of low tide.  Subtidal foraging is not limited in this way, but it is limited by body temperature.  As ectothermic animals, iguanas must rely on their environmental temperatures to regulate their internal body temperature.  The duration of their foraging underwater in the cool seawater is limited by their need to return to land to warm up their bodies in sunshine.  Contrary to Darwin's inference, marine iguanas cannot swim in the sea for very long, not so much because they need to avoid predation by sharks, but because they need to avoid the declining body temperature from prolonged swimming in the cool seawater.

Darwin also failed to see the conflict here between sexual selection for mating and natural selection for foraging.  Sexual selection favors larger males over smaller males, and larger males must forage subtidally.  But larger males need more food, and when food is scarce, they die of starvation.  During El Nino events in Galapagos, sea surface temperatures increase, and there is a decrease in cold ocean currents and cold nutrient-rich upwellings.  Consequently, the green and red algal species disappear and are replaced in intertidal areas by brown algae, which is hard to digest for iguanas.  During the most severe El Nino years, up to 90% of the marine iguanas can die, and the largest iguanas have the highest mortality rates.  So while sexual selection favors a large body size for males, natural selection favors a small body size.

Amazingly, natural selection has produced an adaptive response to the El Nino environment for marine iguanas.  During El Nino, the body length of adult marine iguanas shrinks by up to 20%, apparently through bone absorption, and then after the El Nino passes, their bodies grow in size.  Those individuals that shrink more during El Nino survive longer. This is the first report of shrinkage in adult vertebrates (Wikelski and Thom 2000).

This looks like a good example of the explanatory power of the Darwinian theories of natural selection and sexual selection, which produce awkwardly conflicting adaptations. 

Or do the proponents of scientific creationism and intelligent design theory have a better explanation?  If this is the work of the Intelligent Designer, why didn't He do a better job?  Did the Intelligent Designer create the marine iguanas for the Galapagos and nowhere else?  When, how, and why did He do this?

One possible response from scientific creationists is that God did not have to specially create marine iguanas for the Galapagos; rather, He created the family of iguanids as a "kind," which included a genetic potential for producing the traits of marine iguanas as an adaptation for the environment of the Galapagos.  In the Galapagos, there are at least 11 species of iguanids--7 species of lava lizards, 3 species of land iguanas, and 1 species of marine iguanas.  All of these species could stem from an original pair of iguanids that was on Noah's Ark 4,500 years ago.  Some of their iguanid ancestors floated on vegetation to the Galapagos Islands, where their pre-designed genetic potential for evolving into 11 species was expressed as adaptations to the Galapagos environment.  So these scientific creationists concede that the evolution of new species does occur without any divine intervention, but it occurs only within the boundaries of the "kinds" that were originally created by God (Hennigan 2009; Wood 2003). 

This theory is empirically testable, because it predicts that we should be able to find the genetic potential for the evolution of all species in the genome of each "kind" or taxonomic family.  It also predicts that all speciation has occurred within a few thousand years.  Both predictions are empirically falsifiable.

I will return to this theory of scientific creationism as applied to Galapagos in a future post on "Finding God in Galapagos."


Alcock, John. 2013. Animal Behavior. 10th edition. Sunderland, MA: Sinauer Associates.

Darwin, Charles. 2004. The Voyage of the "Beagle." Washington, DC: National Geographic Adventure Classics.

Hayes, William K., Ronald Carter, Martin Wikelski, and Jeffrey Sonnentag. 2004. "Determinants of Lek Mating Success in Male Galapagos Marine Iguanas." In Allison Alberts, Ronald Carter, William Hayes, and Emilia Martins, eds., Iguanas: Biology and Conservation, 127-47. Berkeley: University of California Press.

Hennigan, Tom. 2009. "Darwin's 'Imps of Darkness': The Marine Iguanas of the Galapagos." Creation 31 (2): 28-30.  Available online.

Jouventin, Pierre, Anne Charmantier, Marie-Pierre DuBois, Philippe Jarne, and Joel Bried. 2007. "Extra-pair Paternity in the Strongly Monogamous Wandering Albatross Diomedea exulans Has No Apparent Benefits for Females." Ibis 149: 76-78.

Vitousek, Maren N., Dustin Rubenstein, and Martin Wikelski. 2007. "The Evolution of Foraging Behavior In the Galapagos Marine Iguana: Natural and Sexual Selection on Body Size Drives Ecological, Morphological, and Behavioral Specialization." In S. M. Reilly, L. D. McBrayer, and D. P. Miles, eds., Lizard Ecology: The Evolutionary Consequences of Foraging Mode, 491-507. Cambridge: Cambridge University Press.

Wikelski, Martin, and Corinna Thom. 2000. "Marine Iguanas Shrink to Survive El Nino." Nature 403: 37-38.

Wood, Todd. 2003. "Mediated Design." Impact, #363.  Available online.

Saturday, March 11, 2017

The Violent Attack on Charles Murray at Middlebury College and the Intellectual Poverty of Higher Education

On March 2, Charles Murray was at Middlebury College to speak about his book Coming Apart, which can be seen as an explanation of the plight of the white underclass in America that supported Donald Trump.  He was not allowed to speak, however, because of the organized mob violence of the students.  Professor Allison Stanger, a Middlebury professor who was to participate in the discussion with Murray, was attacked by the students, and she had to go to a hospital for treatment.  You can easily find videos of the violence on the Internet.  Here's one account of what happened from Inside Higher Ed.  Professor Stanger has written an article for the New York Times.

So what provoked this student violence against Murray?  Faculty and students said they were reacting against Murray as a racist, a white supremacist, and a eugenicist.  The evidence for this, they said, was his book The Bell Curve, a controversial book about how IQ might explain some of the class structure of American society.  Some of the protestors have admitted that they have not read that book or anything else written by Murray.

This is a deeply disturbing sign of where we are headed--possibly a time of mob violence to enforce an illiberal suppression of speech on college campuses and elsewhere.

Before Murray arrived at Middlebury, 450 alumni of the college signed a letter protesting his appearance and arguing that he should not be permitted to speak.  They quote from a statement of the Southern Poverty Law Center that Murray is a "white nationalist" who "uses racist pseudoscience and misleading statistics to argue that social inequality is caused by . . . genetic inferiority."  But notice that they do not cite any passages in any of Murray's writings that would support this claim.  I see no evidence that any of  these 450 alumni have read anything written by Murray, much less that they have actually studied and thought about what he has written.  They show no knowledge of Murray's argument that genetically based racial differences in average intelligence and social behavior should be "no big deal" in a free society with equality of opportunity in which there's a chance for all to find valued places for themselves in society.

There is a lesson here about what should be done when controversial speakers are invited to speak on college campuses.  In my classes, I require students come prepared to every class: they have a reading assignment, and they must write a short essay on the reading, copies of which they share with me and with members of their journal group.  As a result, not only have all the students done the reading, they must have thought about the reading's arguments in order to write a response.  Consequently, when they come to class, they are prepared to participate in a lively discussion of the issues raised in the readings.

Why shouldn't something like this be done when controversial speakers are coming to a campus.  Before Murray's speech, Middlebury had weeks during which the students and the faculty could have been reading some selections from his writing, and they could also have read some of the critical responses to his writing.  They might have met in discussion groups to debate the issues raised by the readings.  The primary question for these discussions might have been: Is there evidence in Murray's writings to support the Southern Poverty Law Center's claim that he is a "white nationalist"? 

I have always questioned the value of "lecturing" in college.  Instead of giving a lecture, should Murray have been invited to lead a discussion of his writings, with the condition that those students and faculty participating would have been required to have done some homework--reading, writing, and talking about his writings as well as critiques of his writings?  Is this something that students and faculty at Middlebury College never do?

Isn't this--reading, thinking, and talking about ideas--what faculty and students are supposed to be doing at a college?

Some of the issues that should have come in discussions of Murray at Middlebury are suggested in my series of posts on Murray's writing here, here, here, here, here, here., and here. 

Friday, March 10, 2017

Natural Law at Cambridge: Kantian Normativity, Catholic Antiliberalism, and Natural Human Law

On March 4th, I participated in a conference at the University of Cambridge.  I was in Cambridge for four days, where I had a room in Pembroke College, which was founded in 1347, making it the third oldest of the Cambridge colleges.  For me, this is a reminder that some of the oldest human institutions are universities.


                                                                     Pembroke College

The conference was entitled "Law as a Guide to Justice: A Symposium on the Philosophical and Theological Foundations of Law and Justice in Honour of Amanda Perreau-Saussine Ezcurra (1971-2012)."

                                                 Amanda Perreau-Saussine de Ezcurra

Most of the participants were friends of Amanda.  Although I did not know her, I can tell by the testimony of her friends that she was a remarkable human being.  The last years of her life were shadowed by premature death--first, the death of her first husband, and then her own death 18 months later from cancer at the age of 41 in 2012.  At the time of her death, she was a Fellow of Queens College, and University Lecturer in Law, at the University of Cambridge.  Her primary academic intellectual interests were international law and the philosophy of law.  She was a devout Catholic who was an energetic and faithful member of the British Catholic community, particularly British Catholic professors.  Cambridge University has had some prominent Catholic philosophers--Elizabeth Anscombe, for example. 

There is some oddity here considering the history of Cambridge University as an integral part of the Anglican Communion initiated by Henry VIII's secession from the Catholic Church.  For a long time, degrees at Cambridge were granted only to those professing the Anglican faith, and every graduate had to declare belief in the Thirty-nine Articles.

Amanda wrote her thesis on John Finnis, another Catholic philosopher.  Although she admired his work in reviving interest in natural law among analytic philosophers through his book Natural Law and Natural Rights, she differed from him in her understanding of natural law.  One difference was that she thought Thomistic natural law could be rooted in some manner in the natural sociability of evolved human nature, while Finnis's Kantian interpretation of natural law rejected any such appeal to biological nature.  This explains why I was invited to present a paper at this conference: my argument for a Darwinian science of Thomistic natural law echoes some of her thinking.

It seemed fitting to me that I should be travelling to Cambridge to make my Darwinian arguments just one month after returning from my second trip to the Galapagos.  In 1827, after giving up his studies to become a medical doctor at the University of Edinburgh, Charles Darwin provoked the anger of his father who exploded: "You care for nothing but shooting, dogs, and rat-catching, and you will be a disgrace to yourself and all your family."  His father warned him that he needed some kind of respectable profession, and his father suggested that becoming an Anglican clergyman might be just what he needed.  So his father sent him to Cambridge for an Arts degree at Christ's College that would be the first step towards Holy Orders.  He arrived in Cambridge in January of 1828.  Although he had little interest in theology, Darwin did enjoy studying with the natural philosophers at Cambridge--particularly, John Henslow, professor of botany, and Adam Sedgwick, professor of geology.

                                     Darwin's College Room at Christ's College, Cambridge

                                                                     Christ's College

But then, while away from school on a holiday in August of 1831, Darwin received a letter from Henslow telling him about Captain Robert FitzRoy, who was looking for someone who would be a companion for him and a naturalist on a voyage of the Beagle to do a coastal survey of South America for the British Navy.  That changed his life--instead of becoming a country clergyman, he would become a naturalist who would develop one of the biggest ideas of science.

Darwin's big idea has been elaborated in a tradition of evolutionary science that includes evolutionary explanations of morality and law that influenced some of Amanda's thinking about natural law.  In an unfinished book, entitled Law as a Guide to Justice: Old Questions for New Natural Lawyers, she wanted to show how the evolutionary biology of social animals--as set forth by people like Jane Goodall and Frans de Waal--could show the evolved natural sociability manifest in human nature that might support natural law.  In contrast to Kantian philosophers like Finnis, who claim that natural law depends on pure reason alone, she wanted to show that prior to human reason there are natural needs and inclinations that provide the grounds for natural law.  She also wanted to show how this natural law could be seen as implicit in statutory law, customary law, and divine law. 

Her untimely death kept her from developing her ideas in a finished book.  The purpose of the Cambridge conference was to have the participants pursue the questions she wanted to raise and perhaps carry out some of the work she had wanted to do in her book.  Previously, I have written a post with my comments on the conference papers and a link to the Dropbox file that has all the papers.

My biggest surprise is that apparently at Cambridge University they rely on lecturing rather than on open discussion among participants who have read something beforehand and are prepared to discuss what they have read.  I distributed weeks ahead of time an extensive set of comments on all the papers for the conference to all the participants.  Except for James Murphy and James Stoner, no one responded to my comments.  No one else circulated any comments on the papers.  And at the conference, I heard no evidence that anyone had read all the papers and was prepared to talk about the papers.  Moreover, the organizers of the conference indicated that they had intentionally made it impossible for anyone attending the conference to read the papers for the conference.  This is very different from the academic culture that I know at the University of Chicago, St. John's College, and the Liberty Fund, where one assumes that everyone participating in some discussion has read the readings for the gathering and is prepared to discuss them.

As I listened to the discussions at the conference, I thought about three main questions:

Must normative nature transcend empirical nature? 

Must the Catholic tradition of philosophy be anti-liberal?

Is human law derived from natural law?

The conference began with comments by Onora O'Neill, The Baroness O'Neill of Bengarve.  She is a prominent moral philosopher at Cambridge, perhaps best known for her books interpreting Kant.  She spoke about her conversations with Amanda, who was interested in Kant's understanding of judgment and how that might apply to legal interpretation.

O'Neill related that Amanda once asked a Cambridge professor about whether there was any consistent theme in the work of Alasdair MacIntyre, given the many shifting positions that he has taken over his life, and the answer was one word-- "Anti-liberalism!"

I noticed that many, maybe most, of the speakers at the conference were anti-liberal Catholics like MacIntyre.  I wondered about that.  Aren't they happy that liberal ideas like tolerance and religious liberty have prevailed at places like Cambridge, so that the tradition of Anglican intolerance has been overturned, and Catholics are free to profess their faith without persecution?  Don't Catholics like MacIntyre embrace such liberal ideas?  If so, then how can they be anti-liberal?

If they are anti-liberal Catholics, does that mean that they reject Vatican II and the Catholic Church's acceptance of religious liberty and the admission that the Church's tradition of persecuting heretics was wrong?  I assume not.

Anti-liberal Catholics like MacIntyre like to scorn what they see as the consumerism, materialism, and secularism of modern liberal culture and then insist that this cannot satisfy the human longing for transcendent spirituality expressed in religious communities.  But they do not consider how liberalism promotes the moral and religious liberty that allows people to pursue their spiritual quest in association with others who share their spiritual commitments.  Aren't British Catholics like Amanda and her friends better able to live their spiritual lives because of the triumph of liberal culture in Great Britain and elsewhere?

Anti-liberal Catholics like MacIntyre like to argue that Aristotle and Aquinas better understood the need for the moral and intellectual virtues for human flourishing than do modern liberal thinkers.  But they don't confront the argument of those like Deirdre McCloskey that modern liberalism promotes the bourgeois virtues, which include all the virtues recognized by Aristotle and Aquinas, and perhaps even the supernatural virtues of faith, hope, and charity.

The second introductory speech was by Tobias Schaffner, who presented the four central questions of Amanda's book as the questions around which this conference was organized.

(1) Is there a benign law-like ordering of the world and especially of human nature?  Part of Amanda's answer to this question was to point to the chimpanzee behavior studied by Goodall and de Waal as showing an animal nature that is both selfish and social that might be manifest in human nature as well.

(2) How do we derive exceptionless natural laws from our sociable nature?  Amanda's answer to this question was to appeal to Aquinas's account of the precepts of natural law as corresponding to the order of the natural inclinations, which suggests that there are vital needs or desires that constrain legal and political reasoning.  Whether this gives us "exceptionless" natural laws, as Amanda thought, is not so clear, it seems to me.  After all, Aquinas stressed the variability in the circumstances of human social life that require prudential judgments about what is best for particular individuals in particular situations.  Amanda's interest in human judgment about the indeterminate circumstances of life points to this problem.

(3) Can positive law, customary law, and divine law be our guide to natural law?  If Aquinas is correct about human laws being derived from natural law, then we should be able to see human laws implicitly pointing to natural law, even when human laws do not explicitly invoke the idea of natural law.  This made me want to reexamine what Aquinas says about this (ST, I-II, q. 95, a. 2).  For example, the U.S. Constitution never explicitly speaks of "natural law" (unlike the Declaration of Indepedence).  Does that mean that there is no natural law reasoning in the Constitution?  Or is it possible that natural law reasoning is implicitly required for interpreting the Constitution?  For instance, does "due process of law" in the Fifth Amendment imply some standard of natural justice?  Does the Ninth Amendment's reference to unenumerated rights "retained by the people" imply natural rights?

(4) Is there a benign structure and providential ordering sustaining the natural order and representing the foundation of natural law?  Does natural law depend on the theological belief in "a benign structure and providential ordering" of the world, which Christians like Amanda can embrace?  If natural law is really natural, and separated from divine law, as Aquinas says, does this mean that people without such religious belief can recognize natural law through their natural experience of the world and of their human nature?

The four sessions of this conference corresponded to this four questions.

John Cottingham (University of Reading) answered the first question by arguing that natural law does indeed depend on "a benign law-like ordering of the world and human nature" by God.  (I first met John in 2010 in Beijing at a conference on evolution and ethics where he made a similar argument against grounding ethics in evolutionary science.)  He distinguished between two senses of the word "nature."  According to the traditional premodern "theistic worldview," he explained, nature is a normative reality as created by God.  According to the modern "secularist worldview," nature is an empirical reality studied by science.  Nature is normative if one agrees with Cottingham that human beings by nature have a divinely implanted light of conscience by which they can see what is objectively right and wrong as determined by God.  Nature is only empirical, however, if one believes that human moral judgment is rooted in human desires, inclinations, or emotions, and thus the moral standard is purely subjective.  I would say that Cottingham's distinction here corresponds to Ed Wilson's distinction (in Consilience) between transcendentalist ethics and empiricist ethics, except that Wilson, in contrast to Cottingham, takes the side of empiricist ethics as rooted in the evolved moral sentiments of human nature, without any necessity for invoking God or divinely implanted conscience.

In my written comments on Cottingham's paper, I asked him whether he thought human beings could recognize and follow natural law even if they had no theistic religious beliefs.  In his oral presentation, he answered yes.

This made me wonder in what way Cottingham sees the "theistic worldview" as superior to the "secularist worldview."  He seemed to say that theism is intellectually superior to secularism in that theism can give a more intellectually satisfying explanation of natural law as derived from God's eternal law.  But then he left it unclear as to whether theism is also practically superior to secularism in that theism is better in practically motivating good conduct.  If that is what he is saying, then this is an empirically falsifiable prediction: we should be able to find evidence that moral conduct on average was better in premodern Europe as dominated by theistic belief than in modern Europe as dominated by secularism.  So, for example, it would seem that Cottingham would have to challenge the evidence for declining violence in history as surveyed by Steven Pinker and others, because declining violence would seem to show moral improvement in European history.  (I raised these questions in my written comments.)

Cottingham did not answer my questions in my written comments about whether he agreed with me that natural law can correct the divine law of the Bible--for instance, with respect to the violence and the support for slavery in the Bible.  Nor did he answer my questions about whether he agreed with Popes John Paul II and Benedict XVI in asking forgiveness for the faults of the Catholic Church in promoting religious violence.

In the Bible and in human history generally, we often see theistic believers inflicting violence on innocent people.  If natural law allows us to condemn this as wrong, doesn't that show that we need an empiricist ethics to correct the mistakes of a theistic ethics?

In the next session of the conference, Nicholas Lombardo (The Catholic University of America) and I spoke in favor of the idea that natural law can arise from our sociable nature (the second question).  Lombardo argued that the Mosaic law presupposes natural law.

I then summarized some of my arguments for Darwinian science as supporting Thomistic natural law. Patrick Riordan (Heythrop College, London) responded to my paper with three points. 

He questioned my methodology in arguing that I selectively picked out only those kinds of animal behavior that might look good to us (like monogamous mating and parental care of offspring) and passed over the brutal violence of animal behavior that we would see as bad. 

For his second point, he quoted MacIntyre's observation (in Dependent Rational Animals) about my "illuminating argument, designed to show how Aquinas's theses about the natural law are compatible with a biological understanding of human nature" (125); and he suggested that it was better to say that human biological nature was "compatible" with Thomistic natural law than to make the stronger claim that human biological nature "supports" Thomistic natural law.

For his final point, he indicated that I had failed to properly distinguish human "goods" and the "precepts" of natural law.

I didn't respond to the last point, because I didn't understand exactly what he was saying, which is probably my fault.

To the first point, I answered by indicating that I had not in fact ignored the harsher side of animal behavior.  For example, in the section of my paper on monogamy among birds, I noted that while monogamous birds might be socially monogamous, they were not always sexually monogamous or genetically monogamous, because they showed many "extra-pair copulations," and thus they did not satisfy Aquinas's standards for monogamy.

To the second point, I answered that Aquinas's heavy reliance on animal biology did seem to indicate that he saw this as "support" for natural law as rooted in biological nature.

MacIntyre's Dependent Rational Animals is a fascinating recognition by MacIntyre that Aristotelian and Thomistic moral philosophy depends upon biological nature.  In After Virtue, MacIntyre had argued that he wanted his defense of Aristotelian virtue ethics to be independent of Aristotle's "metaphysical biology," which was not rationally defensible.  But then after reading my Darwinian Natural Right, MacIntyre changed his mind; and in Dependent Rational Animals, he declared: "I now judge that I was in error in supposing an ethics independent of biology to be possible" (x).  He saw two reasons for this.  The first is that one must explain how human biology makes a moral life possible for human beings.  The second is that human biology explains the human vulnerability that makes us dependent on other human beings--particularly, the dependence of the young and the old.  Dependent Rational Animals lays out the biological basis of the moral life.

In the question period, James Bernard Murphy (Dartmouth College) made the argument that if our evolved natural desires were adaptive for the ancient environments of our evolutionary ancestors, they might not be adaptive for us today, and thus not normative for us.  So, for example, if our ancestors evolved a taste for sugar, that would not necessarily be good for us today, where the abundance of sugar allows us to ruin our health with too much sugar.  My response was to say that this illustrates the need for judgment in managing our desires.  Our desire for health can motivate us to see the need to moderate our  desire for sugar.  This was part of the general point that I made in my oral presentation that while the good is the desirable, the desirable is not necessarily whatever we happen to desire at any moment.  We often discover that we have been desiring something that is not truly desirable for us, and our practical judgment allows us to correct our mistake.  Moral judgment thus requires a combination of reason and desire, as Aristotle argued.

Cottingham also questioned me about whether Thomistic natural law requires a teleology that is denied by Darwinian biology.  I answered by pointing to the argument in my paper that Darwinian biology relies on immanent teleology, although it rejects cosmic teleology.  Cottingham and others at the conference argue that Thomistic natural law really does require a cosmic teleology--that is, the conception of the whole world as a benign order created by a providential God.

The next session of the conference was on Amanda's third question and entitled "Positive State Law as a Guide to (Natural) Justice."  Gerald Postema (University of North Carolina School of Law) spoke about his paper on Matthew Hale's "common-law naturalism."  The respondent was Judge James Crawford of the International Court of Justice.

Against the claim of some scholars that Hale was a legal positivist, Postema argued that Hale saw the common law as derived from natural law.  Postema did not respond to my questions in my written comments about whether Hale's endorsement of witchcraft trials and of the principle that husbands cannot be tried for raping their wives shows that Hale's judgment of natural law was distorted by his bias against women.  I can only assume that Postema believes that Hale's legal judgment in these cases of witchcraft and rape is irrelevant to any account and assessment of his jurisprudence.

Judge Crawford said that he was not a scholar of Hale's jurisprudence, and therefore he could not comment on Postema's interpretation of Hale.  Instead of that, he spoke about the failures of the "additive theory of international law" as proposed by legal positivists--the idea that international law can be explained as custom that has been recognized as law.  He questioned whether it as possible to rccognize custom as law without seeing the norm inherent in custom, suggesting that custom must manifest some natural standard of justice.  He also questioned how it was possible to do something for the first time and recognize this as custom.

The next speaker was James Stoner (Louisiana State University) summarizing his paper on how we can rightly distinguish the work of the legislator from the work of the judge in American constitutionalism by applying Aquinas's distinction between human law as a determination of natural law and human law as a deduction from natural law: the American legislator is concerned with determination, while the American judge is concerned with deduction.

In my written comments, I said that Stoner's paper is confusing, because he says that there is a "mixture of deduction and determination in legislative activity" (18), and he also says that "a mixture of deduction and determination appears as well in the reasoning of judges" (18).  In an email message to me, Stoner said that in claiming that determination ought to belong to the legislative power alone, he was not saying that determination alone ought to belong to the legislative power; and he said that the mixture for judges came from judges being bound by the determinations of others.

In his oral presentation, Stone did not explain what he meant in his paper by "the natural law moment in constitutionalism" (17).  But he seemed to say that even without any explicit reference to natural law in the Constitution, all law, including American constitutional law is either a determination of or a deduction from natural law.

What does this say, for example, about the antebellum debate over the constitutional status of slavery?  If slavery was contrary to natural law, does that mean that the constitutional protection for slavery should have been overturned by an appeal to natural law, because an unjust law is not really a law?  Or does natural law allow for some prudential compromise with slavery insofar as it is constitutionally protected? 

Nigel Simmonds (University of Cambridge) was the respondent for Stoner's paper.  But instead of responding to Stoner's paper, Simmonds briefly summarized the central idea of his book Law as a Moral Idea (2008).  In that book, he argued that "law is the set of conditions for jointly possible freedoms."  Although he presented this as a Kantian idea, it could just as easily be seen as a Lockean idea.  Oliver Wendell Holmes famously ridiculed the idea that law is "a brooding omnipresence in the sky."  But Simmonds argued that there is a sense in which this really is true.  Law is not just a heap of statutes and precedents, as Holmes seemed to claim, because law really is an ideal edifice, in that laws must be interpreted as a good faith attempt at doing justice, and adjudication is the working out of the law as an ideal edifice of justice.

The final session of the conference was on "When and Why are Positive Laws a Guide to Justice?"  James Murphy began by speaking about his paper on the modern idea of human rights as possibly an modern expression of the idea of natural law.  He spoke of two possible theological arguments and one possible philosophical argument justifying human rights.

The most commonly expressed theological argument, and the one that Murphy accepts as a Catholic, is the teaching of the Old Testament that all human beings are created in the image of God, which can be interpreted as declaring the equal moral dignity of human beings as endowed by their Creator with rights, which is affirmed in the famous language of the Declaration of Independence.

The second theological argument is attributed by Murphy to Nicholas Wolterstorff, a Calvinist who affirms total human depravity and thus denies that human beings deserve to be treated with equal dignity.  According to Wolterstorff, the moral dignity of human beings supporting human rights must be seen as an undeserved gift from God based on the New Testament teaching that all human beings will be redeemed on the Last Day for an eternal life in friendship with God.

The Universal Declaration of Human Rights of 1948 does not appeal to any such theological ideas, because such ideas will not be accepted by those many human beings who lack such religious beliefs.  There is, however, Murphy argues, a philosophical justification for human rights that does not require religious belief--"our genetic capacities for personhood" that are shared by all human beings as long as they retain the human genome. 

In fact, the Universal Declaration of the Human Genome and Human Rights, ratified by the United Nations in 1998, the 50th anniversary of the first Universal Declaration, affirms this: "The human genome underlies the fundamental unity of all members of the human family, as well as the recognition of their inherent dignity and diversity," and

And yet, Murphy's respondent--Raffael Fasel (a graduate student at the University of Cambridge)--insisted that the only philosophical justification for human rights would have to based on normativity through and through without any reference to biological facts, because there will always be human beings with genetic disorders that deprive them of any potential for full personhood.  Fasel thus expressed the common assumption among many modern moral philosophers that the only proper grounding for ethics must be a transcendental normativity beyond the empirical nature of human life.  Oddly, Fasel did not identify any argument for the transcendental normativity of human rights, although he seemed to think there was such an argument somewhere.

The Christian arguments for human rights based on Biblical theology fail, because the idea of the equal moral dignity of all human beings as endowed with equal human rights cannot be found in the Bible, in either the Old or the New Testaments.  For the Bible, human dignity is not equal and universal, it is hierarchical and comparative.  The Bible accepts the patriarchal household and social inequalities: wives are commanded to obey their husbands, and slaves are commanded to obey their masters.  Moreover, those who have been chosen by God as His people are superior to those He has rejected.

One Biblical verse that might be cited as supporting the equal dignity of all human beings as created in God's image is in Psalm 8: "For thou has made him a little lower than the angels, and hast crowned him with glory and honor."  But then, in the immediately following Psalm 9, the psalmist thanks God for destroying his enemies: "the enemy is wiped out--mere ruins forever--you have annihilated their cities, their memory has perished" (9:6).  Of course, the Bible is full of such bloody violence as God annihilates Israel's enemies in the most brutal ways.  Speaking to Moses, God commands the "curse of destruction" in which every living being in a town must be killed--men, women, and children (Deuteronomy 20:10-20)--although the young women who are still virgins should be kept alive so that they can be raped by the Hebrew men (Numbers 31).  Enemies can also be enslaved.  And, indeed, the Bible generally supports slavery.

Moreover, the violence commanded by God is directed not just to external enemies but also to Hebrews who displease God.  A long list of crimes--including children cursing their parents, homosexuality, and blasphemy--are to be punished with death.

Some parts of the New Testament seem supportive of universal humanitarianism.  But even so, Jesus is clear that when he returns for the Day of Judgment, he will separate the sheep from the goats, the sheep being rewarded with eternal life, and the goats punished with eternal fire (Matthew 25:31-46).  Amazingly, Wolterstorff glosses over this, implying that all human beings will be redeemed, and none will go to Hell eternally.  Moreover, the final book of the New Testament--Revelation--conjures up bloody apocalyptic battles at the end of history, which has inspired fanatical religious violence for thousands of years, including the recent terrorism of the Islamic State.

Doesn't this show us that we need natural law here to correct the Bible?  Isn't that what many Christians and Jews today have done in reinterpreting the Bible as teaching love, tolerance, and liberty--in other words, liberalism?

Fasel's objection to Murphy--that biological facts cannot provide the normativity necessary for true morality--is the same objection that Frances Cobbe made to Darwin's evolutionary account of the moral sense as rooted in human nature.  Cobbe insisted that human morality cannot be fully explained without some belief in "the Kantian doctrine of a Pure Reason, giving us transcendental knowledge of necessary truths," or in the idea that "the voice of Conscience is the voice of God."  She warned that Darwin's rejection of the Kantian view of morality as transcending natural human experience would destroy morality.  Similarly, contemporary philosophers like Richard Joyce assume that by definition moral judgments presuppose belief in a transcendent world of moral facts beyond the empirical world of natural facts.  If there are no such eternal moral facts, Joyce laments, then morality becomes fictional.

But as I have argued in a previous post, Joyce admits that a strong sense of transcendent moral duty can often support an authoritarian morality that leads to atrocities.  Fanatical religious believers have carried out their divinely commanded moral duty to kill infidels.  Many of the Nazi philosophers were neo-Kantians who believed in "eternal values" and in Nazism as fulfilling that eternal moral order.  The Nazi regime was organized around a strict communitarian morality of sacrificing selfish interests for the good of the community.

Impicitly, Joyce and other Kantians must ultimately subordinate their categorical imperatives of moral duty to the hypothetical imperatives of prudential calculation, because they recognize that we don't know whether any "must-be-doneness" really must be done unless we have judged that the outcome will be desirable for us!  If so, then they end up agreeing with me that "the good is the desirable," and that as I have argued in a previous post, moral judgments are hypothetical imperatives that give us reasons for acting only insofar as they serve what is truly desirable for us.

Even Kant implicitly conceded this.  In his Groundwork of the Metaphysics of Morals, he said that everyone desires to obey his categorical imperatives, because everyone--"even the most hardened scoundrel"--desires the "greater inner worth of his own person" [einen grosseren inneren Wert seiner Person] that comes only from obeying the moral law and thus becoming a "better person" (Ak 4.454).  In this way, Kant's categorical imperatives are always implicitly reduced to a hypothetical imperative.  If you desire to be a better person with a sense of self-worth, then you ought to obey my categorical imperatives.  This, then, rests on two kinds of empirical claims--that human beings most desire personal self-worth and that obeying Kant's categorical imperatives will achieve that desired end.  So, contrary to what Fasel assumed, our sense of transcendental normativity is ultimately grounded in natural human desires as shaped by human evolution.

The Universal Declaration on the Human Genome and Human Rights clearly indicates that the inherent dignity of humanity supporting human rights arises not from divine creation, nor from some cosmic normativity, but from  natural human evolution.  One product of human evolution is sympathy and the moral emotions of approval and disapproval.  The behavior of human rights activists shows that defending human rights depends not on appealing to theological or metaphysical normativity, but on appealing to sympathy and the moral emotions.  Groups like Amnesty International and Human Rights Watch tell stories or show us pictures of human cruelty.  The more disturbing and vivid the stories and the pictures of cruelty, the more likely we are to feel some identification and thus sympathy with the victims.  We then feel outrage against the perpetrators of such cruelty, and we want them to be stopped and perhaps punished. 

William Schulz is the former Executive Director of Amnesty International USA.  In his book In Our Best Interest: How Defending Human Rights Benefits Us All, he dismisses appeals to God or Nature or Reason as insufficient to sustain the morality of human rights.  Instead, he agrees with David Hume's, Adam Smith's,  and Charles Darwin's argument that morality depends on sympathy and the moral emotions that incline us to care for our fellow human beings.  He concludes: "Robert Frost once observed that poems begin with a lump in the throat, and I think human rights do too. . . . far better than by appeals to God or Nature, is to point to the capacity to identify with others, the capacity for human empathy or solidarity" (24).

The history of the expansion of human rights is therefore to be understood as what Hume and Darwin called "a progress of sentiments" as human beings have been persuaded to extend their sympathetic concern to ever wider circles of humanity.

As I have said in previous posts (here and here), what we see here is a reflective sentimentalism.  Moral judgment combines reason and emotion.  Pure reason by itself cannot move us to action without the motivational power of emotion or desire.  That emotional motivation is not irrational, because we can reflect on our emotions and judge them as warranted or not.  So, for example, we might feel outrage against a government that we believe has violated human rights by attacking innocent people, but if we discover that those people were not really innocent, then our outrage might be allayed.  Human rights activists don't make Kantian arguments about the normativity of human rights.  Rather, they make factual arguments about how people are being treated designed to elicit our sympathy for the victims of cruelty and our outrage against the perpetrators of cruelty.

The failure to recognize how human rights depend on reflective sentimentalism was one weakness in the paper of the last speaker at the conference--Nicholas McBride (University of Cambridge).  He identified the prohibition against torture as the classic example of an "exceptionless norm."  But as I indicated in my written comments on his paper, McBride did not explain the legal history or moral psychology of this modern rule against torture. 

The condemnation of legal torture as a violation of human rights--as "cruel and unusual punishment"--is a clear illustration of how sympathy and the moral emotions generally have sustained the modern movement to human rights.  Historian Lynn Hunt has explained this: "Torture ended because the traditional framework of pain and personhood fell apart, to be replaced, bit by bit, by a new framework, in which individuals owned their bodies, had rights to their separateness and to bodily inviolability and recognized in other people the same passions, sentiments, and sympathies as themselves" (Inventing Human Rights, 112).  Notice that the appeal here is to the natural facts of human nature and human experience without any appeal to theological or metaphysical normativity.