Tuesday, February 21, 2017

The Cambridge Conference on Natural Law: Comments on the Papers

I will be participating in a conference on natural law at the University of Cambridge on March 4th, at the Lecture Theatre LG 18, Faculty of Law.

The papers for the conference can be found in a Dropbox file.

My paper is entitled "The Darwinian Science of Thomistic Natural Law."

Here are my comments on the papers, which I have circulated among all the participants.


Sean Coyle (“Can Natural Laws be Derived from Sociability?”) argues that Aristotle does not derive natural law from human sociability, because Aristotle “has no natural law theory” (1).  To consider the derivation of natural law from human sociability, he claims, one must look to those Christian philosophers who influenced Thomas Aquinas—particularly, Augustine.

I don’t find this persuasive.  It is true that Aristotle rarely uses the term “natural law.”  But he does speak of natural right or what is right or just by nature in the Nicomachean Ethics (1134b17-32).  Moreover, in the Rhetoric, he explicitly speaks about “natural law” (1373b1-22).  As Coyle indicates by his citations, much of Aquinas’s writing about natural law is in his commentaries on Aristotle.

Coyle ignores Aquinas’s reliance on Aristotle’s biological writings (and on Albert’s biology that builds on Aristotle) in explaining the sociability of the social and political animals, including human beings.  This is a big part of my paper.  I realize, of course, that some people will want to argue that I am wrong about this.

Coyle writes: “moral theory cannot rest only upon enlightened self-interest or self-interest modified by the interests of others. Such reciprocity is not morality, but merely the realization that I cannot have the things I want unless you have them too” (4).  This overlooks Aquinas’s argument that the starting point for the natural inclinations is self-love, because each person by a necessity of natural instinct must love himself, and each person extends that love of himself to others as extensions of himself (Arnhart, 15).

Coyle rightly emphasizes the importance for Aquinas of the order of natural inclinations in ST, I-II, q. 94, a. 2.  But he does not notice that this all comes from Aristotle’s biological writing.  And he does not notice the absence of any Biblical citations here.  Of course, Coyle might want to dispute my reading of 94/2.

In speaking about Aquinas on Christian charity and loving one’s enemies, Coyle (8) is silent about Aquinas’s rejection of loving enemies in arguing for the “special virtue of vengeance” (Arnhart, 62).


Coyle and Nicholas McBride (“Equality, Flourishing, and the Existence of Legal Absolutes”) defend the existence of exceptionless norms as part of Thomistic natural law. I doubt this.  I agree that there are enduring patterns in human life that reflect a universal human nature.  But I also see such variability in the temperamental nature of individuals and in biological historicity that make absolutely exceptionless norms unlikely (Arnhart 18-27).

Coyle implies that Aristotle thought there were exceptionless norms (9).  But this ignores Aristotle’s observation that while there is a natural standard of justice or right, “all is changeable” (1134b30).  Aquinas agrees.  Coyle even refers to Aquinas’s declaration that while natural law is generally the same for all human beings, as soon as one moves to particular conclusions for particular circumstances, exceptions appear, and thus the general principles are only “for the most part” (ST, I-II, q. 94, a. 4).

Coyle suggests that Aquinas believes that not stealing and not lying are exceptionless norms (9).  But Aquinas says that it is lawful to steal out of necessity (II-II, q. 66, aa. 6-8), and that it is “lawful to hide the truth prudently, by keeping it back” (II-II, q. 110, a. 3, ad 4).  Coyle hides this latter remark in a footnote.

Coyle says that not killing the innocent is another example of an exceptionless norm.  But he is silent about Aquinas’s claim that God’s command to Abraham to kill Isaac shows that killing the innocent can be right if God commands it (II-II, q. 64, a. 6, ad 1).

Moreover, everything Aquinas says about the virtue of prudence as the judgment of what should be done in particular circumstances suggests the absence of exceptionless norms.

McBride identifies the prohibition against torture as the classic example of exceptionless norms (2, 8).  But he does not explain the legal history or moral psychology of this rule against torture.

One clear illustration of how sympathy and the moral emotions have sustained the movement to human rights is the condemnation of legal torture as a violation of human rights.  Traditionally, torture was regarded as a proper means by which legal aauathorities could extract confessions or punish malefactors.  But, then, in the 18th century, the unjustified suffering of the victims of torture was so vividly depicted by critics as a barbarous violation of human dignity, that there was a broad movement in Europe and North America to ban torture as “cruel and unusual punishment.” 

Historian Lynn Hunt writes: “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).

In his Second Treatise, John Locke had justified the idea of natural rights with two kinds of principles--"divine workmanship" and "self-ownership." If human beings are created by God in His Image, then they have a divinely created worth that cannot be properly denied by those who would deprive them of their sacred rights. But if each human being is naturally inclined to take possession of himself in mind and body, and if each man can see that all other men assert the same self-possession, then this human experience of self-ownership could be a purely secular ground of human rights. The modern move towards understanding human rights as rooted in the secular human experience of empathy and moral emotions relies on Locke's secular principle of self-ownership without the religious principle of divine workmanship.

Even as Hunt stresses the primacy of emotion in this understanding of human rights, she also recognizes the role of reason. Human rights have a kind of "inner logic" or a "kind of conceivability or thinkability scale" (150). She illustrates this by showing how the French revolutionaries were driven by the logic of human rights to extend the circle of humanitarian concern. Declaring that all human beings are equal in their natural rights inevitably inclines us to expand that equal protection to new groups of human beings. So, for example, once the French revolutionary leaders had granted religious liberty to Protestant Christians, this made it easier to see the need for granting liberty to Jews.

Nevertheless, as Hunt shows, that logic of human rights was slowed in the 19th century by various ideological movements--nationalism, scientific racism, and Marxism--that were opposed to universal human rights. The natural human disposition to empathy is constrained by a natural tribalism, so that we feel less concern for those we regard as strangers or enemies. The Volkish nationalism of Hitler and the Nazis was an extreme manifestation of this natural tribalism.

Eventually, however, the moral revulsion against the barbarous atrocities of the first half of the 20th century provoked a renewal of the human rights movement beginning with the Universal Declaration of Human Rights of 1948. We can continue to see the emotional psychology of human rights in the work of governmental agencies and nongovernmental organizations (like Amnesty International and Human Rights Watch) that publicize those brutal practices around the world that elicit our moral repugnance in the service of human rights.

This emotional resonance of empathy expressed in the disgust with cruelty confirms, Hunt concludes, the natural grounding of human rights in human moral emotions. "The history of human rights shows that rights are best defended in the end by the feelings, convictions, and actions of multitudes of individuals, who demand responses that accord with their inner sense of outrage" (213). "The process had and has an undeniable circularity to it: you know the meaning of human rights because you feel distressed when they are violated. The truths of human rights might be paradoxical in this sense, but they are nonetheless still self-evident" (214).

This history of human rights shows, Hunt explains, the complex interaction of genetic nature, neural structures, and cultural history.

"Needless to say, empathy was not invented in the eighteenth century. The capacity for empathy is universal because it is rooted in the biology of the brain; it depends on a biologically based ability to understand the subjectivity of other people and to be able to imagine their inner experiences are like one's own. . . ."

"Normally, everyone learns empathy at an early age. Although biology provides an essential predisposition, each culture shapes the expression of empathy in its own particular fashion. Empathy only develops through social interaction; therefore, the forms of that interaction configure empathy in important ways. In the eighteenth century, readers of novels learned to extend their purview of empathy" (39).

Hunt refers to biological research on the neuroscience of empathy in the brain as showing the roots of the moral emotions in evolved human biology.  This research also shows that some people—psychopaths—have abnormal brains so that they cannot feel these moral emotions, and thus they have no moral sense, because they don’t feel guilt, shame, or care for the suffering of others.  There is no deficit in their capacity for abstract reasoning—they are often very intelligent—so this shows that Kant was wrong to think that moral experience was based on pure reason alone without any emotion.

Gerald Postema’s paper—“Hale’s Common-Law Naturalism”—is an instructive account of Matthew Hale’s understanding of natural law, divine law, positive law, and common law.

I do wonder, however, why Postema is silent about those notorious decisions of Hale—particularly, those regarding witchcraft and rape—that cast doubt on Hale’s legal judgment and whether he rightly understood natural law.

Hale has had a pernicious influence on the legal history of both witchcraft and rape.  In both cases, he showed a misogynistic prejudice that violated the natural law principle of equal treatment under law.  Can Postema defend him against this criticism?

One of Hale’s most influential legal standards concerns rape: “it must be remembered . . . that it is an accusation easily to be made and hard to be proved, and harder to be defended by the party accused, tho never so innocent.”  In fact, this is false.  During Hale’s own lifetime, there were few convictions for rape because of the obstacles facing women who might lodge a rape charge, and because of the likelihood of acquittals.  Moreover, while Hale was deeply skeptical of women claiming to have been raped, he was remarkably credulous in accepting the dubious claims of those who pretended to be victims of women practicing witchcraft.  As Keith Thomas said in his history of magic in 16th and 17th century England, “the accusation of witchcraft was easy to make and hard to disprove.”

In 1662, Hale presided over the trial of two women from Lowestoft who were said to be witches.  By 1662, many people were becoming skeptical of the reality of witchcraft, and as early as 1575 some people who claimed to have been bewitched were tried for perpetrating a hoax.  And yet Hale dismissed the evidence in the Lowestoft case that those claiming bewitchment were hoaxers. 

In the trial report, Hale’s charge to the jury was summarized: “Whereupon, the judge . . . only this acquainted them, that they had two things to inquire after. First, whether or no these children were bewitched? Secondly, whether the prisoners at the bar were guilty of it?  That there were such creatures as witches he made no doubt at all; for first, the scriptures had affirmed so much.  Secondly, the wisdom of all nations had provided laws against such persons, which is an argument of their confidence of such a crime.”  The jury returned a verdict of guilty, and the two women were hanged as witches.

The report of this trial and Hale’s judgment in the case was immensely influential in subsequent trials for witchcraft, partly because of Hale’s high reputation.  The report was cited at the Salem witch trials.

Hale cited the Bible as the evidence of divine law commanding the execution of witches. “Thou shalt not suffer a witch to live” (Exodus 22:18).  Like the Biblical teachings on slavery and homosexuality, here is a case of where we need the natural law to correct the Bible (Arnhart, 54-62, 73-77).

Hale has also had a bad influence on the English law of rape.  He was responsible for the legal rule that husbands cannot be charged with raping their wives.  In Historia Placitorum Coronae, Hale wrote: “the husband cannot be guilty of a rape committed by himself upon his lawful wife, for by their mutual matrimonial consent and contract the wife hath given up herself in this kind unto her husband, which she cannot retract.”  Amazingly, he offered no citation to support this statement.

Many commentators have recognized the absurdity of Hale’s rule.  But when Parliament debated this in 1975, the rule was upheld by MPs who quoted Hale.

If this shows Hale’s unreasonable bias against women, does it show his disregard for the natural law principle of equal treatment under law?  Or will Postema argue that I’m mistaken about this?



James Murphy (“Justifying Human Rights: The Threat and the Promise”) says that those who framed the Universal Declaration of Human Rights in 1948 could agree on a list of human rights, but they could not agree on any philosophical or theological justification for those human rights.

As Murphy indicates, some people have argued that the only justification for human rights is theological, and there have been at least two kinds of theological justifications proposed.  The most common is the argument that the idea of human rights is justified by the Old Testament doctrine that all human beings were created in the image of God, which gives all human beings a moral dignity that they would not have without that idea. 

The second theological justification is Nicholas Wolterstorff’s argument that the New Testament doctrine that all human beings will be redeemed on the Last Day for an eternal life in friendship with God gives them the dignity that justifies human rights.  (Oddly, this suggests that Wolterstorff does not believe in the doctrine of Hell as the eternal punishment for most human beings.)  Murphy observes that Wolterstorff is a Calvinist, and his theological justification for human rights is Calvinist in that it teaches that human beings as totally depraved by original sin have no merit in themselves, and so whatever human dignity they have comes purely as an unearned gift of God.

Murphy argues against Wolterstorff’s theological justification, and Murphy indicates that he prefers the Catholic doctrine of imago Dei as the better theological justification for human rights.

And yet Murphy also endorses a third way of justifying human rights—a philosophical justification of human rights as grounded on “our genetic capacities for personhood” that are shared by all human beings as long as they retain the human genome (12).

I agree with this third way as a biological justification of human rights founded on our evolved human nature, which appeals to a moral anthropology rather than a moral cosmology.  I see evidence that this kind of biological justification of human rights is implicit in the Universal Declaration of Human Rights of 1948 and explicit in the Universal Declaration on the Human Genome and Human Rights of 1998.  (My thinking about this has been influenced by Johannes Morsink’s two books on the Universal Declaration of Human Rights.)

The idea of human rights would seem to depend on the idea of human nature. Although the Universal Declaration of Human Rights never speaks of "human nature," it does refer once to nature in declaring that the family is "natural" (Article 16). Moreover, the references to the "inherent dignity" of "all members of the human family" and the declaration that "all human beings are born free and equal in dignity and rights" implies some shared human nature that is the source of human rights.

Originally, in the drafting of the Universal Declaration, Charles Malik a Lebanese Christian and Thomist proposed the following language for Article 16: "The family deriving from marriage is the natural and fundamental group unit of society. It is endowed by the Creator with inalienable rights antecedent to all positive law." The drafters accepted the first sentence but rejected the second, because they wanted a purely secular statement that did not depend on religious belief. Similarly, proposals to refer in Article 1 of the Declaration to human beings as "created in the image and likeness of God" were not adopted. The drafters of the Declaration thought that the shared repulsion towards Nazi barbarism and the determination to declare a universal morality of human rights that would condemn such barbarism manifested a natural morality that did not depend on religious belief. This cosmopolitan morality of human rights must somehow be grounded in human biological nature.

Here is how the Declaration begins, with the first two recitals of the Preamble:

"(1) Whereas recognition of the inherent dignity and of the equal and inalienable rights of all members of the human family is the foundation of freedom, justice and peace in the world,

"(2) Whereas disregard and contempt for human rights have resulted in barbarous acts which have outraged the conscience of mankind, and the advent of a world in which human beings shall enjoy freedom of speech and belief and freedom from fear and want has been proclaimed as the highest aspiration of the common people."

Article 1 declares: "All human beings are born free and equal in dignity and rights. They are endowed with reason and conscience and should act towards one another in a spirit of brotherhood."

The reference to "barbarous acts which have outraged the conscience of mankind" reminds us, of course, that the Declaration was largely an expression of shared moral revulsion against the Holocaust and the other horrors of Nazism in World War II.  The phrase "conscience of mankind" generalizes from the feelings of outrage that people around the world felt in response to the radical evils of Nazism. Thus, the Universal Declaration of Human Rights shows us how we derive "rights from wrongs" (a phrase used as the title of a book by Alan Dershowitz). That is to say, we formulate "rights"--justified entitlements to special treatment--from our experience of shocking injustices. The Declaration shows how moral outrage against atrocities expresses a universal morality that can be formulated as human rights rooted in the inherent dignity of all human beings.

At one point in the drafting process, there was another reference to nature. It was proposed that Article 1 should declare that all human beings "are endowed by nature with reason and conscience." As an alternative to this language, the Brazilian delegation proposed: "Created in the image and likeness of God, they are endowed with reason and conscience . . ." Similarly, the Dutch delegation proposed that the first recital of the Preamble should state: "Whereas recognition of the inherent dignity and of the equal and inalienable rights of all members of the human family, based on man's divine origin and immortal destiny, is the foundation of freedom, justice, and peace in the world."

These proposals for religious language about human beings as created in God's image provoked intense debate. Some of the drafters saw a stark opposition between God and nature as alternative sources for human reason and conscience. Bogomolov of the USSR attributed the phrase "by nature" to "French materialist philosophers." Finally, the Brazilians agreed to withdraw their religious language if the phrase "by nature" were dropped, and a consensus formed on this resolution of the dispute.

At one point, a proposed amendment would have changed "by nature" to "by their nature," which conformed to Malik's recollection that "the intention of the Commission on Human Rights had not been to imply that man was endowed with reason and conscience by an entity beyond himself."  It is regrettable, I think, that the drafters did not go with this phrase "by their nature," because this would have clearly suggested their understanding that the source of human rights is neither a transcendent God nor a transcendent Nature, but human nature.

In at least one of the recent documents on human rights, the biological basis of human rights in human nature is explicitly recognized. The Universal Declaration on the Human Genome and Human Rights was adopted by UNESCO in 1997 and then ratified by the General Assembly of the United Nations in 1998.

The first three articles are put under the title "Human dignity and the human genome":

Article 1
“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. In a symbolic sense, it is the heritage of humanity.”
Article 2
“a. Everyone has a right to respect for their dignity and for their rights regardless of their genetic characteristics.
“b. That dignity makes it imperative not to reduce individuals to their genetic characteristics and to respect their uniqueness and diversity.”

Article 3
“The human genome, which by its nature evolves, is subject to mutations. It contains potentialities that are expressed differently according to each individual's natural and social environment, including the individual's state of health, living conditions, nutrition and education.”

Here we can see much of the complexity and tension in appealing to human biology as a ground for human rights. Universal human rights assume a "fundamental unity of all members of the human family," which in turn assumes an underlying unity in the human genome, because membership in the human species requires some shared genetic basis.

And yet the human genome brings about not only the unity of humanity but also its diversity. No two human beings are genetically identical. Even identical twins are not really identical.  So even if human beings are roughly equal at birth in being identifiably human, they are not completely identical. Here we can see the implicit worry that some human beings might be excluded from the human family because of genetic differences that some people would consider abnormal or inferior.

We can also see here the fear of genetic reductionism. Although being genetically human is the precondition for being treated with the dignity that human beings deserve, human beings are not fully reducible to human genetics.

The human genome is recognized as a product of evolution and thus subject to evolutionary change through mutations. But there is enough genetic stability to sustain the reality of the human species.

That genetic humanity consists of potentialities that are diversely expressed in each individual through the interaction with the natural and social environment of the individual, which includes physical conditions, bodily functions, and social learning.

Human genes by themselves do nothing. They shape human life only though genetic potentialities working through complex interactions with the physical and social world. That's why human biology is much more than genetics. The biological nature of human beings depends on the coevolution of innate tendencies, social history, and individual life history.

The universality of human genetic nature allows for universal human rights. But the moral history of human rights will reflect the complex contingencies of social and political history.
We can see then that this Universal Declaration on the Human Genome and Human Rights of 1998 supports Murphy’s claim that human rights can be rooted in the uniquely human capacities of the human genome.  Religious believers like Murphy can see that human genome as bearing God’s image.  But even those who lack such religious belief can see the grounding of human rights in human nature.  Thus, natural law can stand on its own natural ground independently of any belief in divine law (Arnhart, 69-81).


James Stoner argues that 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.

Stoner’s paper is confusing, however, in that he seems to contradict himself.  He says that “determination ought to belong to the legislative power alone” (12).  But he also says that there is a “mixture of deduction and determination in legislative activity” (18).  He says that “the sort of reasoning involved in judicial decision seems to be deductive in character” (13).  But he also says that “a mixture of deduction and determination appears as well in the reasoning of judges” (19).

As far as I can tell, Aquinas does not distinguish between the legislator’s determination and the judge’s deduction.  Instead of that, Aquinas distinguishes between legislators as making general rules for the future and judges as deciding particular cases in the present (I-II, q. 95, a. 1, ad 2).

Stoner’s paper suggests other questions as well.  When he says that “common law belongs in a sense to both jury and judge” (7), does this include jury nullification as an exercise of natural law reasoning—as, for example, in the exercise of jury nullification to overturn the fugitive slave laws in the U.S. as contrary to natural justice?

What exactly does he mean by “the natural-law moment in constitutionalism” (17)?  Does he mean that the U.S. Constitution implicitly appeals to natural law?  If so, how and where?  In the Preamble?  In the 9th Amendment?  In the 14th Amendment?  Is the Declaration of Independence part of the constitutional system?  Some of the legislators who framed and ratified the 14th Amendment said that the clause protecting “the privileges or immunities of citizens of the United States” incorporated all the natural rights invoked in the Declaration of Independence.  Does Stoner agree with this as part of “the natural-law moment in constitutionalism”?

If Aquinas is right that every human positive law is derived from the natural law (I-II, q. 95, a. 2), does that mean that constitutional law must be interpreted in the light of natural law?  So, for example, does that mean that the debate in Obergefell v. Hodges over whether same-sex marriage is a constitutional right is necessarily a debate over the natural law of marriage (Arnhart, 54-62)?

Saturday, February 18, 2017

Thinking About Galapagos (3): The Evolution of Iguanas, Finches, and Humans by Hybridization

Marine Iguana

                                                                   Land Iguana

Hybrid Iguana from Breeding of a Male Marine Iguana and Female Land Iguana
Video of Marine Iguana Feeding Underwater
South Plaza Island, Looking Towards North Plaza Island

                                                       A Video on the Hybrid Iguana

On Day 3 (January 30), I began the day before sunrise, sitting on the balcony of our stateroom, reading and writing in my journal.  As the sun came up, I saw South Plaza Island, a small island (measuring one tenth of a square mile), near the even smaller island of North Plaza, which are off the east coast of Santa Cruz island.  From my reading, I knew that one of the unique features of South Plaza is that it is the only place where hybrid iguanas have been found. 

Both marine iguanas and land iguanas are unique to Galapagos.  The marine iguana is the lizard in the world that swims and forages for food underwater.  DNA analysis has shown that hybrid iguanas have a marine iguana father and a land iguana mother.  This is surprising because not only are marine iguanas (Amblyrhynchus cristatus) and land iguanas (Conolophus subcristatus) separate species, they even belong to separate genera.

Marine iguanas have sharp claws that help them grip the rocky seafloor, and they have flat faces that allow them to eat up algae off the rocks.  Hybrid iguanas also have sharp claws and flat faces, but they have never been observed foraging in the sea.  Instead, they forage for food on land like the land iguanas, but unlike the land iguanas, the hybrid iguanas can use their sharp claws to climb trees and cactus in search of food.

Hybrid iguanas show no defects that would impede their survival, but they do not seem to be capable of reproducing, although some scientists think they might turn out to be fertile.  In fact, many hybrid animals have proven to be capable of reproducing.

Howard Snell, a biologist at the University of New Mexico, was the first person to notice the hybrid iguana on South Plaza in 1977, and he saw that the hybrid iguana had features that were intermediate between the marine iguana and land iguana.  From 1977 to 2000, Snell has seen as many as 16 hybrids.  They are so rare that many naturalist guides who have visited South Plaza many times have never seen one.

Luckily, our group saw one hybrid iguana shortly after we had landed on the small wooden dock on South Plaza and then climbed up the lava rocks.  Snell has identified one hybrid individual who was often near the wooden dock.  And since iguanas can live long lives (30  years or more), it's possible that we saw the same individual.

So here's another example of how the evolution of life forms can depend on the unique natural history of a small island.  South Plaza provides the "Goldilocks conditions" that are "just right" for producing hybrid iguanas.  First, the island is so tiny that there is not enough room for land iguanas and marine iguanas to live in separate habitats.  Since their territories overlap, they frequently come into contact, and thus  they have many opportunities for interbreeding.  The second condition is that on South Plaza the breeding seasons of land iguanas and marine iguanas overlap: when male marine iguanas are ready to mate, the female land iguanas are at the end of their breeding season.

If animals from different species can crossbreed to produce hybrids, and if some of these hybrid animals can be fertile, this challenges the traditional belief of Biblical creationists that the Creator created all species to be eternally separate and fixed.  For example, in Jean-Jacques Rousseau's Emile, the Savoyard Vicar argues that the complex order in living nature proves the existence of God as the intelligent designer of that order, and part of that order is the existence of species that are eternally separate.  The Vicar insists: "The generation of living and organized bodies is by itself an abyss for the human mind.  The insurmountable barrier that nature set between the various species, so that they would not be confounded, shows its intentions with the utmost clarity.  It was not satisfied with establishing order.  It took certain measures so that nothing could disturb that order" (Bloom trans., p. 276).

Early in his life, the naturalist taxonomist Carolus Linnaeus (1707-1788) agreed with this traditional belief that the natural order of created species could never be disturbed: "there are as many species as the Infinite Being created in the beginning."  But as he worked more in the classification of species, he discovered plants that were hybrids, some of which were capable of reproducing, and thus becoming a new species.  He concluded: "it is impossible to doubt that there are new species produced by hybrid generation."  For this, he was denounced by clergy who accused him of blasphemy in denying the Biblical account of God's special creation of species.

Later, creationist naturalists like Joseph Gottlieb Kolreuter (1733-1806) and Carl Friedrich von Gartner (1772-1850) studied hybrids to try to prove that Linnaeus was wrong, arguing that the hybridization of two species could not produce a new species, because God had specially endowed hybrids with sterility. 

In his chapter on "Hybridism" in The Origin of Species, Darwin argued against "the view commonly entertained by naturalists . . . that species, when intercrossed, have been specially endowed with sterility, in order to prevent their confusion."  He pointed out that the degree of sterility was innately variable in individuals of the same species, and that some species could cross with other species and produce fertile hybrids.  Darwin did not explore, however, the possibility that hybridization could be a means for the evolution of new species.

Over the past 150 years, most biologists have recognized the evolution of new plant species through hybridization, but they have generally assumed that this is uncommon for plants, and that it never happens for animals.  And yet, in recent decades, the evidence for the evolution of hybrid animals has  become too extensive to ignore.  Biologists like Matthew Arnold of the University of Georgia and James Mallet of the University College London has led the intellectual movement for recognizing the evolution of animal species by hybridization (Mallet 2007; Pennisi 2016).

This new evidence for evolutionary speciation through hybridization subverts the once long-accepted "biological species concept" of Ernst Mayr, which assumes that reproductive isolation is the critical element of any species, so that members of a species breed only with other members of their species.  The evidence for hybridization shows that the barrier to interspecies reproduction is much weaker than Mayr believed.

Once two species mate and produce fertile hybrid offspring, evolution can occur in two ways.  If the hybrid mates back with a member of the parent species, new DNA is introduced into the genome of the parent species, which is called introgression.  If hybrids mate among themselves and reproduce, this creates a new species.  Introgression introduces much more genetic variation more quickly than is possible through random mutation, which means that hybridization can help organisms adapt better and more quickly to changing environments.

Darwin introduced the image of the evolution of species as a tree of life, as in this famous page in his notebooks, where he drew a tree of life and wrote "I think."


Some devoted Darwinians have even had this tattooed onto their bodies!  But if the idea of the evolution of new species by the hybridization of old species is correct, then we need to draw connections between the branches of this tree, so that the tree of life would become more like a web of life.

The Galapagos hybrid iguana is not a clear example of this, insofar as there is doubt as to whether it can be fertile.  A better example is the Galapagos finches as studied by the Grants on Daphne Major.  In 1981, the Grants noticed the arrival of an unusual male finch that they called "Big Bird."

            "Big Bird," a Hybrid Darwin's Finch on the Galapagos Island of Daphne Major

He had a big head.  He weighed 28 grams, instead of the 18 grams typical for male finches.  And he sang an unusual song.  He probably originated on Santa Cruz Island from the mating of a cactus finch and a medium ground finch.

At first, Big Bird and his offspring consorted with the medium ground finches on Daphne Major.  But then after a severe drought from 2003 to 2005 killed 90% of the finches on the island, the two surviving Big Bird descendants and their 26 offspring crowded together in one corner of the island, and they breed just among themselves, which suggests that they are becoming a separate species.  Because of their intermediate-size beaks, they can crack certain seeds that other birds can't.  The unusual song that they sing also separates them from other birds.  So the effect of hybridization on evolution here is partly cultural--the social learning of song.

Recently, the Grants have been cooperating with geneticists to identify the genes responsible for the size and shape of finch beaks, which explains the genetic basis for beak variations and for the evolution of the intermediate-size beaks of the hybrid finches (Lamichhaney et al. 2015).

So the descendants of Big Bird are beginning to look like a new species that evolved through hybridization, although the Grants are unwilling to say that this really is a new species.

Hybridization has occurred not only among iguanas, finches, and many other animals, but also among human beings.  In 2010, analyses of the nuclear DNA of ancient and living humans showed that they carried traces of DNA from Neandertals and from archaic humans from Denisova Cave in Siberia.  It seems that Europeans and Asians have inherited 2% to 6% of their nuclear DNA from Neandertals.  And people living in Southeast Asia have inherited about 5% of their DNA from the Denisovans.

If this evolution by hybridization is true, this refutes the traditional creationist claim that all species have been created by God to be eternally separated.  It also subverts the argument of people like Leon Kass that genetic engineering--moving genes from one species to another--should elicit moral repugnance as an unnatural act of "playing God."  After all, it appears now that nature has been engaged in genetic engineering for millions of years.  And we can still see that evolutionary genetic engineering in action in the island laboratories of Galapagos.


Lamichhaney, Sangeet, et al.  2015.  "Evolution of Darwin's Finches and their Beaks Revealed by Genome Sequencing." Nature 518 (19 February): 371-75.

Mallet, James. 2007. "Hybrid Speciation." Nature 446 (15 March): 279-83.

Pennisi, Elizabeth. 2016. "Shaking Up the Tree of Life." Science 354 (18 November): 817-21.

Thursday, February 16, 2017

Thinking About Galapagos (2): Islands of Life

                              A Panoramic View of Pinnacle Point on Bartholomew Island

On Day 1 (January 28), my wife and I landed at the Baltra airport.  There we met the five other passengers for our cruise on the Cormorant (a German couple from Switzerland, a Canadian couple from Montreal, and an American living in Ecuador) and our naturalist guide (Xavier).  On the boat, we had lunch, and then we navigated to our first site for hiking--Bachas Beach on Santa Cruz island, where we saw sea turtle nesting sites and American Flamingoes in the lagoons behind the beaches.

On Day 2 (January 29), we navigated to Bartholomew Island in the morning for hiking to the top of the island, and then snorkeling at the foot of Pinnacle Point to see sharks, rays, and the Galapagos penguins.  In the afternoon, we moved to Sullivan Bay on Santiago Island for hiking on a lava field.

I soon found myself thinking about one idea that stayed with me throughout this trip--every one of these islands is a world unto itself that is geologically, biologically, and culturally unique because of its unique natural history, and thus the Galapagos Islands make it easier to see how all of life could have evolved on islands. 

This idea was nicely stated by Loren Eiseley in an essay on the Galapagos: "It is the working of such mysterious principles as adaptive radiation and selection which binds this assemblage of extraordinary plants and animals together and relates even the story of man to island tortoises and flightless birds. We are all, in fact, the product of islands, visible or invisible. At some point in the fossil past, isolation and mutation have diverted each bit of life down some solitary road from which there is no turning back."

After all, the Earth itself is an island in the Cosmos, with a unique natural history that has made it the only place, as far as we know, in which life has emerged.  And even if we do someday discover life on another island planet in the universe, we can expect that it will have forms of life unlike those on Earth, because it will have its own unique history shaped by contingent events and circumstances.

An example of the unique geological and biological history of Santiago Island is a large lava flow at Sullivan Bay created by a volcanic eruption in 1889.  There have been more recent lava flows--the most recent was in May of 2015 from Wolf volcano on Isabela Island.  But this lava field on Sullivan Bay is the most recent lava flow in Galapagos that is open to visitors.  So it's an opportunity to see how these islands originate from volcanic eruptions and also to see how life originates on barren lava.

Galapagos Pahoehoe or Ropy Lava

Mollugo crockeri Plant on Lava


                                                                        Lava Cactus

Looking over the massive expanse of bare lava, it's hard to imagine how life could ever take root here.  And yet after about 45 minutes of hiking, we saw Mollugo crockeri, which is the first plant colonizer on this lava, and this species is found only on Santiago Island and no where else in the world.  Then, after an hour of hiking, we saw a Lava Cactus, which is also endemic to Galapagos, and found only on barren lava flows.  Mollugo is a perennial herb.  It's flowers are white with five petals.  As the leaves die, they eventually create soil, although it takes over 5,000 years to build a layer of soil on lava.

So here we see the origins of plant life on the volcanic islands of Galapagos.  We must assume, however, that these plants unique to Galapagos--and in the case of Mollugo crockeri, unique to Santiago Island--evolved from ancient ancestral species that found their way to Galapagos from the South American continent.  Critics of Darwinian science might object that this is only a speculative assumption--a "just-so story" unsupported by empirical evidence.

And yet Darwin treated this as a testable theory.  First, we can predict that there must be plant species on the mainland that are similar enough to these species endemic to Galapagos as to be plausible candidates for the evolutionary ancestors of these plants.  Second, we can predict that there must be some way for the seeds of these ancestral plants to reach the Galapagos Islands, which are 600 miles from the mainland--either by being blown through the air, by floating on the ocean currents, or by being carried through the air by birds, or by being brought to the islands by humans.

In his Origin of Species, Darwin has two chapters on "Geographical Distribution," in which he reports the results of many years of experimentation at his home in Down to test the possible ways that seeds might have travelled from a mainland continent to distant oceanic islands like Galapagos.  He put the seeds of eighty-seven different plant species in salt-water for weeks at a time, and then he planted them to see if they would germinate.  Most of them did germinate.  He noted that many seeds sank in water.  But when plants were dried, some of them would float.  He then checked the average speed of currents in the Atlantic Ocean (from A. K. Johnson's Physical Atlas), and he calculated that the seeds of 14 out of every 100 plant species belonging to one country could float across 924 miles of sea to another country.  He also tested the possibility that seeds could be carried across an ocean in the carcass of a dead animal.  He fed a pigeon on seeds, killed the pigeon, and then floated its body on salty water for a month.  He then dissected the body, planted the seeds, and discovered that most of them germinated.

This illustrates how evolutionary theory can be experimentally tested.  By contrast, the proponents of "scientific creationism" and "intelligent design theory" never engage in the experimental testing of their theories.  Thousands of scientists have gone to Galapagos to empirically study the evolution of species in the islands.  Much of this research has been supported by the Charles Darwin Research Station in Puerto Ayora on Santa Cruz island.  But there is no Creationist (or Intelligent Design) Research Station supporting empirical research in Galapagos, because Creationism and Intelligent Design Theory are not empirically testable theories.

And yet, while Creationism and Intelligent Design Theory have no positive content as testable theories of the origin of species, they do have some negative content insofar as they criticize evolutionary science for its intellectual weaknesses, which forces evolutionary scientists to strengthened their reasoning.

So, for example, creationists and intelligent design proponents have criticized evolutionary theory for failing to become an empirically proven science, because no scientist has ever directly observed the evolution of new species from ancestral species.  We can directly observe the Mollugo plant and the Lava Cactus growing on the lava field in Sullivan Bay.  We can see that these plants are endemic to Galapagos.  We can see that they are similar to plants on the mainland of South America.  And we can test the possibility that seeds from the mainland could find their way to Galapagos.  But we cannot see the evolution of one plant species into a new plant species on Galapagos.

Now, of course, there is at least one evolutionary research project on Galapagos that has become famous as showing "evolution in action"--the study of the history of finches on the Daphne Major island by Peter and Rosemary Grant.  And yet, despite the way their work is reported in high school and college biology textbooks, there is some dispute as to whether they have really seen the macroevolution of one species into another.  I will return to this in a later post.

As I indicated in my previous posts on my first trip to Galapagos in 2013, I have been surprised that all of the ecotourists and the naturalist guides that I have met in Galapagos assume that the truth of evolutionary science has been proven, and that much of the proof is found in Galapagos.  And consequently, Creationism and Intelligent Design Theory seem ridiculous to them.

That impression was confirmed the night of our second day, while the Cormorant was anchored in Sullivan Bay, when all of the passengers stayed up late drinking some good wine and talking about the evolution debate.  The conversation included Kjetil Haugan, the Norwegian businessman who owns Haugan Cruises, which operates the Cormorant and two other yachts cruising Galapagos.  He travelled with us for a few days, on his way to a business meeting in the islands.  The Europeans and the Canadians were completely baffled that Americans were still debating evolution.  I explained my debates with creationists and intelligent design proponents (particularly those at the Discovery Institute).  And I also explained that many American politicians (like Vice President Pence and Ben Carson) were vocal opponents of evolutionary science.  All of these people on the boat thought that the Galapagos Islands provided irrefutable evidence for the origin of species through Darwinian evolution.  Moreover, this commitment to evolutionary science as a way to explain the universe was part of their global liberal culture as cosmopolitan ecotourists.  As you might expect, we also talked about Donald Trump, who was just as baffling to these global liberal Europeans as the religious opponents of evolution.

I will have more to say about this in future posts.

Sunday, February 12, 2017

February 12: Darwin Day, Lincoln Day, and Galapagos Day

Today is the birthday of Charles Darwin and Abraham Lincoln, who were born on this day in 1809.  It is also "Galapagos Day," because on February 12, 1832, there was a formal ceremony to mark Ecuador's formal acquisition of the Galapagos Islands.

For this day, I have written an essay on Darwin and Lincoln for the Starting Points journal, which is edited by Adam Seagrave at the University of Missouri for the Kinder Institute on Constitutional Democracy.

Wednesday, February 08, 2017

Thinking About Galapagos: Divine Creation? Intelligent Design? Darwinian Evolution?

Having completed my second cruise around the Galapagos Islands on board the Cormorant, I have spent a total of 24 days in the Galapagos.  Of the 14 notably large islands, I have been to 11.  I have also been to some of the dozen or more small islets.  I have been there both in the hot and wet season (January to May) and the cool and dry season (June to December). 

My first trip, in June of 2013, included a week on the island of San Cristobal, in the town of Puerto Baquerizo Moreno, where I participated in a special meeting of the Mont Pelerin Society, cosponsored by the Universidad San Francisco de Quito, on "Evolution, the Human Sciences, and Liberty."  In July of 2013, I wrote a series of blog posts on my cruise around the islands and on the lectures and discussions at the MPS conference.

On board the Beagle, Charles Darwin anchored near the northwest end of San Cristobal on September 16, 1835.  On October 20, the Beagle sailed away from the Galapagos.  During his time there, Darwin walked on four islands--San Cristobal, Floreana, Isabela, and Santiago.

Like Darwin, I have found that Galapagos is good for thinking--particularly, for thinking about the origins and history of life on Earth. 

So, for example, consider the Galapagos tortoise--the animal from which the name Galapagos is derived.  The giant tortoise is one of the many species that are endemic to Galapagos--that is, found naturally only in Galapagos.  It is also one of the many species that varies across the islands.  When Darwin was on Floreana, he was told by Nicholas Lawson, the Ecuadorian Vice-Governor of Galapagos, that he could tell which island a tortoise came from by the shape of its shell.  For example, some of the tortoise shells are dome-shaped (as in the first picture above), and others are saddleback-shaped (as in the third picture).  The saddleback tortoises live predominantly on the low islands--like Pinta, Pinzon, and Espanola.  The dome-shaped tortoises live predominantly on the larger and higher islands with highland areas that get more moisture and thus have denser vegetation.  It is generally assumed that saddleback shells allow tortoises to stretch their necks to reach vegetation that is high up, while dome-shaped shells are more adapted for feeding on dense vegetation near the ground.  It is believed that there are at least 10 existing species of Galapagos tortoise and at least 2 extinct species, although there is disagreement as to whether these are really distinct species or sub-species or varieties of one species.

This raises lots of questions.  Why is the Galapagos tortoise unique to Galapagos?  Where did it come from?  If it came from an ancestral species on the mainland of South America, how did the ancestor make the trip across 600 miles of ocean?  And once it arrived, how and why did it radiate out over the islands and become different on the different islands?  How could it survive and reproduce on such inhospitable volcanic islands?  Does this show the macroevolution of new species from ancestral species?  Or does it only show the microevolution of varieties within a single species?

The Galapagos tortoise has been driven to the edge of extinction by competition with invasive species, such as black rats that eat tortoise eggs and goats that eat up the vegetation that tortoises need.  Is this an example of Darwinian survival of the fittest?  Or is this an unnatural disruption by human beings of the balance of nature?  Does Darwinian science suggest that there is no such thing as a fixed balance of nature, but only a constant evolutionary flux?  Should we intervene to restore the conditions for the survival and reproduction of Galapagos tortoises?  If so, what would motivate us to do that?

There are at least three general kinds of answers to these questions.  Galapagos tortoises arose either by divine creation, by intelligent design, or by Darwinian evolution.

There are various ways in which God could have created them.  If one is a young-earth Biblical creationist who accepts Bishop James Ussher's chronology, then one believes that God created the Earth and all species of life, including the Galapagos tortoise, in 6 days 6,000 years ago.  If one is an old-earth creationist, then one believes that God could have taken millions of years to create all the species of life.  A creationist who reads the Bible as literal scientific history will believe that all the species were on Noah's Ark, and that after the great flood subsided, the Galapagos tortoises somehow migrated from Mount Ararat in the Middle East to the Galapagos Islands.  But why did the giant tortoises migrate to Galapagos and no where else on Earth?

The Bible speaks of God creating the "kinds" of life (in the King James translation).  And so some scientific creationists argue that "kinds" might refer not to species but to some higher level of modern taxonomy--maybe "genus," "family," or "order."  This is necessary, they argue, to explain how there could have been enough room on the Ark for two of each "kind" of life, but not for each species.  So God did not have to specially create the Galapagos tortoise.  He could have created "kinds" of reptiles, and then Galapagos tortoises and other species of reptiles could have evolved naturally within these "kinds."  But doesn't this concede a lot to the action of natural evolution rather than divine creation?  Is this theistic evolution?

In 2002, Mike Pence delivered an entire speech in the House of Representatives endorsing creationism and intelligent design and rejecting evolution. “I believe that God created the known universe, the earth and everything in it, including man,” Pence said.  “And I also believe that someday scientists will come to see that only the theory of intelligent design provides even a remotely rational explanation for the known universe.”  He also argued that the signers of the Declaration of Independence affirmed this in declaring that human beings were created in God's image and thereby endowed with inalienable rights.  So Darwinism contradicts the American creed.  We can expect that as Vice President, Pence will continue to promote this position, which he shares with other members of the Trump administration.

In the early 1800s, the great French naturalist George Cuvier proposed a new form of creationism that he thought conformed to the fossil record, which shows a long history of species emerging and going extinct.  There could be a series of creation events and extinctions over a long time, and these could be explained as miraculous interventions by God or by creative forces within nature. 

This latter view was taken by David Porter, commander of the U.S. frigate Essex, who cruised the Galapagos from April to September in 1813, and wrote about this in his Journal of a Cruise Made to the Pacific Ocean.  (The drawing above of the Galapagos tortoise is from Porter's book.)  "I shall leave others to account for the manner in which all those islands obtained their supply of tortoises and iguanas, and other animals of the reptile kind," he wrote.  "I shall merely state, that those lands have every appearance of being newly created, and that those perhaps are the only part of the animal creation that could subsist on them."  Porter asked, "Nature has created them elsewhere, and why could she not do it as well at those islands?"  But if this creative force is natural, is there any need for divine creation?

Another alternative, favored by the folks at the Discovery Institute in Seattle, is Intelligent Design Theory.  Instead of looking to the Bible as a literal scientific history of creation, we can infer that all forms of life, including the Galapagos tortoise, were created by an Intelligent Designer, regardless of whether we identify that Designer as the God of the Bible.  But as I have indicated in my posts on Intelligent Design, the proponents of Intelligent Design Theory rely on a sophistical rhetoric of negative argumentation--arguing that Darwinian scientists have not yet explained the step-by-step process by which every species has evolved--without themselves explaining where, when, how, and why the Intelligent Designer created the Galapagos tortoise and all other species of life.

Darwinian evolution can be understood as a radical alternative to both divine creation and intelligent design in explaining the origins of Galapagos tortoises and all other forms of life.  But as Darwin himself suggested, natural evolution can also be understood as compatible with some forms of divine creation or intelligent design.  One can see natural evolution as showing the "secondary causes" of life, while the Creator or Intelligent Designer can be seen as the "primary cause" of those laws of nature that make evolution possible.  This is the theistic evolutionism adopted by a long line of thinkers from Asa Gray to C. S. Lewis to Francis Collins.

When Darwin was in the Galapagos Islands, he was not yet a Darwinian evolutionist.  Contrary to the common legend, Darwin did not have a "eureka" experience when he saw the Galapagos tortoises or finches.  It was not until he returned to England in 1836, and began to study his notebooks and the specimens he had collected during his voyage, that he slowly began to move towards his theory of evolution by natural selection.

While he was on the Beagle, Darwin was reading Charles Lyell's new book The Principles of Geology, Lyell revived and extended the evolutionary geology of James Hutton's Theory of the Earth, which argued that the Earth was not permanently fixed in its form by God at the beginning, but was rather in flux, with "no vestige of a beginning--no prospect of an end."  Over millions of years, volcanic mountains could be pushed up from beneath the ocean's floor to become islands that could be weathered back down to create soil to become inhabitable by human beings, but then it could eventually be resubmerged under the sea.  Darwin saw evidence for this in the Galapagos.

In his Voyage of the Beagle, published first in 1839, Darwin indicated that he was also astonished by the "creative force" that he saw in Galapagos.  And then in the second edition of this book, published in 1845, Darwin gave his first published hint of his new theory of the transmutation of species: "Hence, both in space and time, we seem to be brought somewhat near to that great fact--that mystery of mysteries--the first appearance of new beings on this earth."

While he was voyaging on the Beagle, Darwin seemed to be a creationist like Cuvier and Lyell, who believed there were "centers of creation" in places like Galapagos.  The giant tortoise and other species unique to Galapagos could be understood as created there.  But then by 1837 and 1838, he was considering a purely natural process of the evolution of new species.  In 1842, he used the term "natural selection."

Eventually, in The Origin of Species (first published in 1859), and later publications, Darwin defended his "theory of natural selection" as better than the "theory of special creation" in explaining the emergence of giant tortoises and other new species in Galapagos and elsewhere.

Galapagos provided three kinds of evidence for his new theory.  First, oceanic islands like the Galapagos have many species unique to them, and this is best explained by the migration of plants and animals from the mainland of a nearby continent, which then must undergo modification to be adapted to their new circumstances.

Second, isolated places like Galapagos lack some types of plants and animals, and their places will be filled by others.  So, for example, in Galapagos, reptiles rather than mammals are dominant, because it was easier for reptiles to reach the islands and then evolve to fill the niches available there.

Third, the distinctive plants and animals of islands like Galapagos resemble the plants and animals of the nearest mainland.  "Why should the species which are supposed to have been created in the Galapagos Archipelago, and nowhere else, bear so plain a stamp of affinity to those created in America?" Darwin asked.  "I believe this grand fact can receive no sort of explanation on the ordinary
view of independent creation; whereas on the view here maintained, it is obvious that the Galapagos Islands would be likely to receive colonists, whether by occasional means of transport or by formerly continuous land, from America."

Of course, the creationist or intelligent design theorist can always say that the Creator or the Intelligent Designer just liked to create species unique to the Galapagos that resembled those on the South American mainland.  But this is nothing more than an unsubstantiated assertion unless there is some scientific explanation of exactly where, when, how, and why the Creator or Intelligent Designer did this.

And so it is that the Galapagos tortoise and the other unique forms of life in Galapagos provoke deep questions about the origins of life.

But not only is the Galapagos tortoise good for thinking, it is also good for eating!  Darwin testified to the good taste of tortoises.  And indeed hundreds of thousands of Galapagos tortoises were taken away from the islands by whalers who stored them on their ships as a ready supply of food, because tortoises can survive for six months or more without food or water.  Even as late as the 1970s, local people in Galapagos were eating tortoises as tasty food for special occasions. 

Galapagos conservationists have had to try to persuade the local people that it's better to preserve tortoises for the pleasures of observing and studying them, and for attracting tourists, than to kill them for food.  The second picture above, showing a naturalist guide hugging a tortoise, illustrates this.

Darwinian scientists and conservationists have to persuade us that preserving or restoring the original conditions of Galapagos before human settlement and the arrival of invasive species is good for us, because it satisfies our evolved human desire for intellectual understanding of the natural world, the desire that sustains the philosophic or scientific life.  That's the argument for Darwinian liberal ecotourism.

Over the next few weeks, I will be writing a series of posts about my most recent tour of Galapagos.

Wednesday, January 25, 2017

Back to the Galapagos!

                                                                 The Cormorant

Today, my wife and I leave for our second cruise on The Cormorant around the Galapagos Islands (January 28 to February 4).  As I did for the first cruise in 2013, I will write a series of posts on our tour after we return.  The posts on the first cruise begin here.  The Cormorant is a yacht that is about the same size as the Beagle on which Darwin sailed.

After our 8-day cruise in 2013, we spent a week in Puerto Baquerizo Moreno, on the island of San Cristobal, where I participated in a special meeting of the Mont Pelerin Society at the Galapagos campus of the Universidad San Francisco de Quito.  The theme of the meeting was "Evolution, the Human Sciences, and Liberty."  I was one of the speakers--speaking on "The Evolution of Darwinian Liberalism."  I wrote a series of posts on all of the lectures and discussions, which begins here. 

This was a wonderful way to think about Darwinian evolution--first following Darwin's steps through the Galapagos as the natural laboratory of evolution, and then thinking about the implications of evolutionary science for classical liberalism at the MPS conference.  On this second trip, I want to continue thinking about how evolutionary science might support liberal social thought.

I realized that one 8-day cruise was not enough time to see the full range of life in the Galapagos.  That first cruise took us to the central, western, and northern islands (Santa Cruz, Isabela, Fernandina, Marchena, and Genovesa) during the cool and dry season of the year.  This second cruise will take us to the central and southern islands (Santa Cruz, Santiago, Santa Fe, San Cristobal, Espanola, and Floreana) during the warm and wet season of the year.

The ecological circumstances of the Galapagos are fundamentally shaped by the geological and climactic conditions.  The geological features of the Galapagos arise fundamentally from the islands being products of volcanic eruptions.  The volcanoes on the western islands of Fernandina and Isabela remain active.  The Wolf volcano in northern Isabela erupted as recently as May 25, 2015.  The volcanoes on the eastern and southern islands are inactive.

Darwin noticed that the volcanoes seem to lie along parallel straight lines.  He inferred that there were rifts on the ocean floor from which lava had been blurted and formed the islands. He spoke of "fissures of eruption."  Today, geologists agree with this, but their story is a bit more complicated.  They see the western islands as sitting on a deep-seated "hotspot" of volcanic activity that periodically sends volcanoes bubbling to the surface of the Nazca plate, which is moving to the south-east. As the Nazca plate moves, it carries each island away from the hotspot like a conveyor belt.

                                             Wolf Volcano Erupting in May of 2015

                                              Plate Tectonics of the Galapagos Islands

The Creation and Movement of Volcanoes in the Galapagos

As the islands move away from the hotspot over millions of years, they eventually sink under the sea.  The newest islands--Fernandina and Isabela--are rugged and inhospitable to life.  The older islands have had time for soil and vegetation to grow on what originally was pure lava, and thus they are somewhat more hospitable to life.

The other fundamental ecological factor for the Galapagos is climactic fluctuations due to ocean currents.

Between June and November, the cold Humboldt Current flowing up from the south lowers the temperature in the islands and causes some moisture in the warmer air to condense into a drizzling mist.  Beginning in December, the warm Panama Current flowing down from the northeast becomes more powerful, which raises the temperature of the water, creates a hot season, and with evaporation from the warmer water, clouds form and rain falls.  During an El Nino year, the Panama Current is particularly warm, which creates heavy rains.

So while in my first tour, I saw the youngest and most volcanically active islands during the cool and dry season of the year; in this tour, I will see the older and volcanically inactive islands during the warm and wet season.  Even in the wet season, however, the rain is confined mostly to the higher elevations, and so those of us who are hiking mostly at lower levels can be comfortable.

For anyone who is thinking about touring the Galapagos, I can recommend The Cormorant and the other two yachts of Haugan Cruises.  It's a luxury cruise with 16 passengers and 11 crew members.  Each stateroom has a balcony.  The food is good. The experienced naturalist guides are intelligent and engaging.  And as I indicated in my previous series of posts on the first trip, the guides offer a well-informed commentary on the evolutionary science of the Galapagos.

Of course, to speak of the evolutionary science of the Galapagos points to the deepest questions raised by any visit to the Galapagos: Does the variety of wildlife in the Galapagos provide evidence for the evolution of species by natural selection and other Darwinian mechanisms?  Or does it rather show the work of a Divine Creator or Intelligent Designer?

How do we explain the origin of those many species of life that are endemic to the Galapagos--species found here and nowhere else in the world?  There are over 4,000 species that are native to the Galapagos.  And of these about 1,600 species (40%) are endemic.  How exactly were so many species produced in these islands?

Those Biblical believers who read the first chapters of Genesis as a textbook of science say that God specially created these 1,600 species for the Galapagos, just as He created all other species.  The proponents of Intelligent Design Theory don't follow this literal reading of Genesis, but they do argue that all species must have been originally designed by some intelligent mind.

Doesn't it seem a little strange that the Creator chose to specially create these 1,600 species for the Galapagos and no where else?

Both the Creationists and the Intelligent Design proponents argue that the failure of Darwinian biologists to explain exactly when, where, and how a process of evolution created these species shows that we must assume that this requires a Divine Creator or Intelligent Designer.

But notice the rhetoric of negative argumentation here.  The Creationists and Intelligent Design proponents challenge the Darwinians to explain the step-by-step pathway by which the species endemic to Galapagos evolved by purely natural causes.  If the Darwinians cannot do this, then it's assumed that this failure proves the truth of Creationism or Intelligent Design. 

The sophistical fallacy in such argumentation becomes clear as soon as one notices that the Creationists and Intelligent Design proponents do not explain exactly when, where, and how the Creator or Intelligent Designer created the species for the Galapagos.  So they don't satisfy the standards of proof that they apply to the Darwinians.

So, for  example, the Creationists and Intelligent Design proponents have conceded that Peter and Rosemary Grant have observed evolutionary change in Darwin's finches in the Galapagos, particularly in the size and shape of their beaks.  But they argue that this is only microevolution--evolutionary change within a species--and not macroevolution--the evolutionary emergence of new species from ancestral species.  And yet, these proponents of Creationism and Intelligent Design have not provided any explanation of exactly when, where, and how God or the Intelligent Designer created the finches and other species endemic to the Galapagos.

The Grants have spent over 40 years of their life carefully studying the finches in the Galapagos as they empirically test hypotheses about evolution.  Have any creationist scientists made the same effort to test their hypotheses about how the Creator did His work in the Galapagos?

There is  another possibility--theistic evolution.  In the beginning, God might have created the laws of nature, but then allowed the natural laws of evolution to create all the species of life, including those endemic to the Galapagos. 

Darwin suggests this in the last paragraph of The Origin of Species:
"It is interesting to contemplate a tangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent upon each other in so complex a manner, have all been produced by laws acting around us.  These laws, taken in the largest sense, being Growth with Reproduction; Inheritance which is almost implied by reproduction; Variability from the indirect and direct action of the conditions of life, and from use and disuse: a Ratio of Increase so high as to lead to a Struggle for Life, and as a consequence to Natural Selection, entailing Divergence of Character and the Extinction of less-improved forms.  Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely, the production of the higher animals, directly follows.  There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved."
The Galapagos  Islands are perhaps the best place in the world to feel the grandeur in this view of life.