So, I’ve decided to try a slightly different approach for the next while—one that has these sorts of folks in mind. From time to time, you can still expect those more in-depth, technical articles, or perhaps a discussion of some new research that makes the popular press, or even an analysis of some new argument from the IDM or RTB. These will be breaks from the new routine, however. For the most part, we’re going to stick to the basics, much like you would if you took an introductory evolution course at a university. Don’t worry, though: this course doesn’t have any prerequisites! All that’s needed is a willingness to learn.

What you can expect

The goal of this course is straightforward: to provide evangelical Christians with a step-by-step introduction to the science of evolutionary biology.  This will provide benefits beyond just the joy of learning more about God’s wonderful creation. An understanding of the basic science of evolution is of great benefit for reflecting on its theological implications, since this reflection can then be done from a scientifically-informed perspective. From time to time we might comment briefly on some issues of theological interest (and suggest resources for those looking to explore those issues further), but for the most part, we’re going to focus on the science. For folks interested in the interaction between science and Christianity, I heartily recommend Ted Davis’ recent series as a fabulous introduction to the topic.

You can also expect a slow, patient pace. Since this course is intended for folks with little or no background in biology, we’re going to take our time to make sure no one gets left behind. This might be frustrating to folks who already know a fair bit about evolution. Hopefully even more knowledgeable readers will learn some new and interesting details along the way—but the goal will primarily be to help folks who are less well versed in evolution increase their understanding.

You can also expect a survey of many different areas that have some bearing on evolution. We’ll examine geology, paleontology, biogeography, genetics, and a host of other topics in order to provide a “big picture” overview. This broad-brush approach means that any given individual post will not necessarily be “convincing” to folks who have doubts about evolution. Think about assembling a large jigsaw puzzle: placing any individual piece, on its own, doesn’t convincingly demonstrate what the overall picture will show. This course will be like that. Each topic we cover will put a few pieces in place here and there, slowly building towards the final overall picture.

Since evolution is an active science, this process will also highlight where there are “missing pieces” that are still being sought by scientists. All of this is well and good, since the purpose of this course is not so much to convince anyone of the validity of evolutionary theory, but rather to inform readers about the nature and scope of evolution as a scientific theory in the present day. My goal is to provide readers with a basic understanding of what evolution is and how it works. Given that as the primary goal, if one finds the scope of the evidence ultimately convincing (or not) is somewhat beside the point. The intent here is to provide readers with information they can use to make their own, informed decision.

How you can help

First and foremost, you can help by spreading the word about this series to folks you think would be interested in learning more about evolution in a non-threatening environment. Secondly, you can help me by asking questions in the comments. One of the challenges of being a specialist is having the ability to put oneself in the shoes of someone just starting out. What might seem obvious to me may not seem obvious to you, and I hope you’ll feel that no question is too basic or too simplistic. If you’re wondering about something, it’s almost guaranteed that other folks are, too! So, please don’t be shy. I’ll do my best to answer questions in the comments, though I hope that some of our more skilled commenters will (respectfully!) help out here, as well. Finally, you can help by letting me know what broader areas of evolution you find confusing. I have my own ideas about what areas of evolution are commonly misunderstood, but I’d love to hear from readers about what areas they find difficult to understand. I’ll use this input to shape the topics I will cover as we go forward.

Getting started

In the next post in this course, we’ll dive into the course content by introducing two key areas: how scientific theories work in general, and how evolution in particular works as the current organizing theory of modern biology. 

Good science has an addiction to theories,¹ and for science to be good science, it must deal with good scientific theories.  What constitutes a good scientific theory?  That is a very involved question, but a user’s view of good scientific theories looks something like this:

1.  A scientific theory is not a guess or suspicion.  For example, “I have a theory about who shot President Kennedy,” reflects the colloquial meaning of the word “theory,” and not the meaning conveyed by scientists when they use the word “theory.”  
2. Scientific theories are convincing explanatory frameworks that efficiently integrate a large body of evidence about the world.  Good scientific theories have the capacity to make sense of a wide range of data that made less sense before the introduction of the theory. 
3. In order to be called a scientific theory, it must have been successfully tested and re-tested many times.²
4. A scientific theory must be falsifiable in order to be truly scientific.  The theory has to live constantly at risk from new data.³ 
5. A theory must have predictive power.⁴  Good theories allow scientists to make predictions based on the theory that, when tested, turn out to be at least roughly correct. 

These are not the only characteristics of a scientific theory, but they probably represent the most important features for practitioners of science. 

If we hold contemporary evolutionary theory to these standards, how well does it do?  Since the inception of evolutionary theory by Charles Darwin in 1859 with the publication of On the Origin of Species, there are four characteristics of evolutionary theory that have endured 150 years of further research:

1. Living species are descendants of other species that lived in the past.
2. These past species lived in populations that underwent gradual transformation so that the individuals in these populations changed their appearance, behaviors, metabolisms, and life histories over long spans of time.⁵
3. New forms of life arose by means of a process called speciation in which one lineage splits into two distinct lineages.  This continual splitting of organismal lineages leads to a nested genealogy of species.  This nested genealogy forms a veritable tree of life, whose root represents the first species to arise and whose twigs represent the millions of species living today.  If you trace back any pair of twigs from the modern species you will find that their histories merge at some node on the tree where the two species share a common ancestor.⁶ 
4. This process of biological change that takes place throughout the advance of geologic time, or evolution, occurs by means of variation in organisms (which we know today is due to genetic mutations) that is acted on by either random genetic drift or natural selection. Those individuals with variations better suited to the current environment leave more offspring, thus changing the average appearance of the population over time and making it a better fit to the environment. This improving fit between organisms and their environment gives the appearance of organisms having been well designed for their milieu.⁷ 

What is the evidence for these aspects of evolutionary theory?  The evidence is actually immense, but I will restrict this discussion to just a few items. 

First there is the fossil record. If life results from a natural process such as biological evolution, then we should observe a progression of fossil organisms that proceed from relatively simple, single-celled organisms in the oldest rocks to more complex, multicellular organisms in younger rocks. When paleontologists examine the geologic column, they perceive that some of the oldest and deepest layers of the geologic column contain fossils of microorganisms, and then marine invertebrates in younger layers above those,⁸ and then much later and higher up in the geologic column fish appear, followed later and higher still by amphibians, and then by reptiles, mammals, and birds.⁹  Thus, the general presentation of the fossil record in the rock record comports exactly with what the theory of evolution predicts. 

However, the fossil story gets even better, because scientists can trace evolutionary trends throughout the fossil record.  For example, horses get bigger, fuse their leg bones and toes into a single bone with a thick hoof and grow the thickness of their tooth enamel;¹⁰ Cenozoic brachiopod shells get narrower, decrease their rib numbers and beak angle;¹¹ diatoms get bigger;¹² and primate fossils reduce the size of their teeth and expand the size of their brains.¹³ 

Additionally, Darwin predicted that there should be organisms preserved in the fossil record that possess features found in two different types of creatures. Such organisms are “transitional forms” that bridge the gap between different types of organisms.¹⁴ However, the fossil record of Darwin’s time provided little evidence of such transitional forms.¹⁵ Therefore, Darwin gambled that future paleontological research would provide sufficient evidence to corroborate his theory. How did this gamble turn out? Since Darwin’s time, paleontologists have discovered transitional fossils that are part fish and tetrapod,¹⁶ part amphibian and part reptile,¹⁷ part dinosaur and part bird,¹⁸ and part reptile and part mammal.¹⁹ Once again, we would predict such paleontological trends and the existence of such transitional fossils if life came about through a process of organic evolution. Clearly paleontological research since Darwin’s time has powerfully vindicated his theory. 

Please join us for part two of this post tomorrow, where we will discuss how signs of evolution can be detected in organisms living today, and how evidence from multifarious scientific fields—not just biology and paleontology—have bolstered the theory of evolution and added to our understanding of how natural selection works.

Notes

1. Ratzsch, Del. The Battle of Beginnings: Why Neither Side Is Winning the Creation-Evolution Debate. Downer’s Grove, WI: Intervarsity Press, 1996. pp. 104–119. 
2. Kitcher, Philip. Abusing Science: The Case Against Creationism. Cambridge, MA: MIT Press, 1983. pp. 45–54.
3. Ibid, 42–48.  .
4. Ratzsch, Del. Science and Its Limits: The Natural Sciences in Christian Perspective. Downer’s Grove, WI: Intervarsity Press, 2000. pp. 21–24. 
5. Hall, Brian K., and Benedikt Hallgrimsson. Strickberger’s Evolution. 5th ed. Burlington, MA: Jones and Bartlett, 2013. pp. 19–68. 
6. Kitcher, Philip. Living With Darwin: Evolution, Design, and the Future of Faith. New York: Oxford University Press, 2009. pp. 43–71. 
7. Futuyma, Douglas J. Evolution. 3rd ed. Sundbury, MA: Sinauer Associates, 2013. pp. 281–343. 
8. Valentine, James W. On the Origin of Phyla. Chicago: University of Chicago Press, 2006. pp. 429–464. 
9. Carroll, Robert L. Vertebrate Paleontology and Evolution. New York: W. H. Freeman and Company, 1990. 
10. MacFadden, “Horses, the Fossil Record, and Evolution,” 131–158; McFadden, Bruce J. “Fossil Horses from "Eohippus" (Hyracotherium) to Equus: Scaling, Cope's Law, and the Evolution of Body Size.” Paleobiology 12, no. 4 (1986): 355–69.; Prothero, Donald R., and R.M. Schoch, eds. The Evolution of Perissodactyls. New York: Clarendon Press, 1989. ; McFadden, Bruce J. Fossil Horses. Systematics, Paleobiology, and Evolution of the Family Equidae. Cambridge, Cambridge University Press, 1993. 
11. McNamara, Kenneth J. “Evolutionary Trends.” In Encyclopedia of Life Sciences (New York: Macmillan Publishers Ltd, 2001), pp. 1–7. 
12. Litchman, E., C. A. Klausmeier, and K. Yoshiyama. “Contrasting Size Evolution in Marine and Freshwater Diatoms.” Proceedings of the National Academy of Sciences USA 106, no. 8 (2009): 2665–2670.
13. Tattersall, Ian. The Fossil Trail: How We Know What We Think We Know About Human Evolution. New York: Oxford University Press, 2008. pp. 89–198. 
14. Darwin, Charles. On the Origin of Species by Means of Natural Selection or the Preservation of Favoured Races in the Struggle for Life. London: Penguin Books, 1985. p. 292.
15. Hunt, Gene. “Evolution in Fossil Lineages: Paleontology and The Origin of Species.” Supplement American Naturalist 176 (2010): S61–S76. 
16. Clack, Jennifer A. Gaining Ground: The Origin and Evolution of Tetrapods. Bloomington, IN: Indiana University Press, 2002; Daeschler, Edward B., Neil H. Shubin, and Farish A. Jenkins, Jr. “A Devonian Tetrapod-Like Fish and the Evolution of the Tetrapod Body Plan,” Nature 440, no. 7085 (2006): 757–63; Shubin, Neil H., Edward B. Daeschler, and Farish A. Jenkins, Jr. “The Pectoral Fin of Tiktaalik roasae and the Origin of the Tetrapod Limb.” Nature 440, no. 7085 (2006).): 764–71; Downs, Jason P., Edward B. Daeschler, Farish A. Jenkins, and Neil H. Shubin. "The Cranial Endoskeleton of Tiktaalik roseae." Nature 455, no. 7215 (2008): 925–9. 
17. Carroll, Robert L. Vertebrate Paleontology and Evolution. New York: W. H. Freeman and Company, 1990. pp. 156–216. 
18. Shipman, Pat. Taking Wing: Archaeopteryx and the Evolution of Bird Flight. New York: Touchstone, 1998. pp. 169–244.  
19. Prothero, Donald R. Evolution: What the Fossils Say and Why It Matters. New York: Columbia University Press, 2007. pp. 271–297. 

A common argument leveled against the theory of evolution is that scientists have not been able to produce the expected transitional fossils that show the change of one species into another. If evolution were true, wouldn’t there be instances of clear intermediary species, like, for example, a species that was half whale and half hippo to show the transition between those two? In this BioLogos podcast, Kelsey Luoma addresses this misconception about what a transitional fossil actually is. Rather than a mix between two related species, transitional fossils point back to the common ancestors that modern species share. The fact is that the number of transitional species is massive and it grows with each passing year. Given the rarity with which organisms are actually fossilized, the amazing thing is actually the completeness of the fossil record, not its incompleteness. The transitional species story strongly supports, and certainly does not disprove, evolutionary theory. ¹

1. To hear the full audio clips which have been referenced go to:

• Rational Response Debate with Kirk Cameron (from Way of the Masters)
• Behind the Scenes with Dr. Neil Shubin (from Cincinnati Museum Center)
• Mark Norell Publishes New Archaeopteryx Findings (from American Museum of Natural Sciences)
• Texas A&M Professor Discusses Findings of Autralopithecus Sediba and its Relationship to Humans (from Texas A&M University)
• Intro/outro music composed by Martin Minor (Minor2Go).

An audio only version of the podcast can be downloaded here.

During the past year the first results were published from the "Encyclopedia of DNA elements" project ('ENCODE'), revealing that at least 20 percent of the genome, perhaps more, is involved in regulating the expression of its 21,000 protein-encoding genes. The "selfish gene" had its day in the sun, but has now been replaced by the image of a finely tuned genomic system in which each type of gene product cooperates via an intricate networking complex to generate the music of life. The vast array of epigenetic signals whereby genes are switched on or off ensures a steady flow of two-way communication between the genome and its wider environments.

The human as a complex, interactive and highly integrated system might not on the face of it seem a fruitful hunting ground for those who see the genes as pulling the strings of life. Nevertheless, the past year has continued to see a growing love affair between the social sciences and genomics. This is well illustrated by a recent article in Nature entitled: "The anatomy of politics -- from genes to hormone levels, biology may help to shape political behavior." The author writes that "An increasing number of studies suggest that biology can exert a significant influence on political beliefs and behaviors," reporting that "genes could exert a pull on attitudes concerning topics such as abortion, immigration, the death penalty and pacifism." The political scientist John Hibbing is quoted as saying that "...it is difficult to change someone's mind about political issues because their reactions are rooted in their physiology."

Geneticists have highlighted the suspect nature of such claims from a purely scientific perspective. But in our present context it is the way that the genetic results are reported that is most striking. Note the dualist language involved and its assumption of genetic determinism. Genes and physiology are seen as something different from "us" and "our mind," and they seem to be controlling us, so we can't even change our mind. Humans are presented as pawns of their biology, puppets dancing to the tune of their genetic masters.

What has all this to do with the "big idea" concerning human identity that the Imago Dei provides? More, it turns out, than initially meets the eye. The clash of ideas here between theology and science comes not at the level of the science itself, which, in this case, remains ambiguous and disputed, but at the level of the ideological packaging of scientific ideas. To see where the clash comes from, we first need to understand the revolutionary nature of the Imago Dei idea in its original context in the texts of Genesis.

For millennia it was uniquely the pharaoh or the king who was seen as being in the "image of a god" in the polytheistic political systems of ancient Egypt and Mesopotamia. Adad-shum-ussur, a court astrologer and cultic official in the seventh century B.C. royal court of Nineveh, made clear that the Assyrian king Esarhaddon is the very image of Bel (Marduk), the top god of that era:

A (free) man is as the shadow of god, the slave is as the shadow of a (free) man; but the king, he is like unto the (very) image of god.

Richard Middleton provides further examples in his book, The Liberating Image, which describes how the stratified urban society of great cities such as Babylon was structured politically, socially and economically round the king's court and the cultic practices of temple worship of the various polytheistic deities of the city. Social destinies were unchanging because rooted in powerful creation myths. Power was in the hands of the privileged few and true freedom belonged only to the king, for only he was in the image of a powerful god.

Would Hebrew thinkers and writers have been familiar with this idea? Almost certainly, yes, since Israel had significant cultural and economic contact with both Egypt and Mesopotamia over prolonged periods, not least during their periods of exile. So how would the original readers of that wonderful theological essay, Genesis chapter 1, have understood these words?:

Then God said, "Let us make adam [humankind] in our image, in our likeness, and let them rule over the fish of the sea and the birds of the air, over the livestock, over all the earth, and over all the creatures that move along the ground." So God created adam in his own image, in the image of God he created him; male and female he created them. [Genesis 1:26-27].

In its historical context, the implications were revolutionary: the kingly and priestly male roles previously allocated to the privileged few by a pantheon of gods were now being delegated instead by the one creator God to the whole of humanity, male and female. In a stroke the entire ruling and priestly structure of Mesopotamian society was delegitimized. The Imago Dei was being democratized and it was now humankind who were to be the significant players in the arena of earthly life, the mandate to rule underlying their new responsibilities. Above all, humanity was set free by the one true God to determine their own destiny, no longer under the yoke of all-powerful dictators, nor under the baleful astrological control of the moon and stars.

Yet, ever since, humans have become experts at re-enslaving themselves, refusing the responsibilities that come with free-choice and submitting instead to narratives of fate and destiny. It seems ironic that today it is not the creation myths of ancient Babylon but the ideological interpretations of biology that provide the narratives of fate, in which genes "pull" humans toward certain political views and people cannot change their minds because their convictions are "rooted in their physiology."

"It's in his or her DNA" is a new phrase becoming increasingly embedded in our language, referring to something that cannot apparently be changed. On Sept. 8, 2012, Brad Pitt was quoted by the Daily Mail as saying that "America is a country founded on guns. It's in our DNA. It's very strange but I feel better having a gun." No it's not in our DNA, Mr. Pitt, either literally or metaphorically. People have choices -- they are the prisoners neither of their genetics, nor of their physiology, nor indeed of their environments. Human beings made in the image of God are free to chart their own destiny in a way that preserves human value and dignity. On that we can leave the last word to Abraham Lincoln: "...nothing stamped with the Divine image and likeness was sent into the world to be trodden on, and degraded, and imbruted by its fellows" (Aug. 17, 1858).

Morality, or more strictly our belief in morality, is merely an adaptation put in place to further our reproductive end.

Important scientific theories invite philosophical and theological reflection. Dawkins, Ruse, and Wilson, have described their conclusions. But scientific theories are often compatible with multiple philosophical and religious interpretations. For example, Newton's laws of motion and gravity allow several competing theistic and atheistic interpretations.

To avoid Ruse and Wilson's philosophical conclusion, we need not dispute their scientific hypothesis about how morality evolved. We need only dispute their philosophical extrapolation as to why morality exists. Even if we restrict ourselves to an atheistic worldview, this extrapolation is questionable. Donald MacKay (1965) would call this an example of "the fallacy of nothing but-tery". This is the assertion that a description of something at one level renders other levels of description meaningless. From our everyday experience, we know that a successful description on one level does not invalidate other levels of description. For example. one might assert that a Shakespeare sonnet is "nothing but" ink blots on a page (MacKay 1965). True, one way to describe a sonnet is to precisely specify the page coordinates of every ink blot. This description is valid and complete on its own level; however, one could also analyze the sonnet linguistically, emotionally, socially, historically, and on other levels. If one is programming an inkjet printer, the most important description is in terms of ink blot coordinates. For almost every other purpose in life, however, that is an unimportant level of description. In the same way, a complete evolutionary description of the existence of morality does not necessarily invalidate the truth, utility, or significance of other levels of description of morality.

If we do not restrict ourselves to atheism and instead allow for the existence of a creator, the extrapolation from how morality evolved to why morality exists fails further. Consider an analogy. Suppose an inventor builds a robot which could do a variety of useful things-- mow the lawn, clean the house, grade homework, write book chapters, and so on. One thing this robot can do, given a complete set of spare parts, is build a replica of itself. Whenever the inventor needs another robot, she gives one robot a set of spare parts and has it build a replica of itself. Amongst all the software subroutines within this robot, there is a set of subroutines that govern the robot's self-replication, including the replication of those self-replication subroutines. Would it be correct to say that the purpose of the robot's existence is merely to reproduce those particular self-replication subroutines? Do all of the other software and hardware of the robot--which allow it to mow the lawn, and so on-- merely further the reproductive ends of those self-replication subroutines? At one level, the robot's hardware and software do serve to reproduce those self-replication software routines. At another level of analysis, however, those self-replication software routines serve the robot to produce more copies of itself. At still another level, those self-replication software routines serve the robot's creator. The creator of the robot should get the last world as to which of those levels of description is most important.

In humans, does morality exist to further the reproduction of certain genes, or do those genes exist in order to allow for the production of new human beings who can behave morally? If human beings have a creator, the creator gets the final word on the question of purpose. The mechanism which the creator used to make those genes-- whether de novo or via evolution-- is secondary. The creator's purpose in creating those genes decides the issue.

References

• Dawkins, Richard. 1976. Pp. 1-11 in The Selfish Gene. Oxford: Oxford University Press.
• MacKay, Donald. 1965. Christianity in a Mechanistic Universe. Chicago: InterVarsity.
• Ruse, Michael, and Edward O. Wilson. 1993. The approach of sociobiology: The evolution of ethics. In Religion and the Natural Sciences, ed. James E. Huchingson. Fort Worth: Harcourt Brace Javonovich.

If a cadre of outspoken, strong atheists wrote a litmus test for scientists, that might very well be question #1.

"Scientists, if you're not an atheist, you're not doing science right," PZ Myers -- a well-known blogger, biology professor and atheist -- regularly preaches.

But if this is true, then as many as half of scientists are doing science wrong. A 2009 study from the Pew Research Center polled members of the American Association for the Advancement of Science (AAAS). Fifty-one percent of respondents reported a belief in a higher power. Does this mean that it's too late for science? Has religion already pillaged the minds of researchers worldwide? No, of course it hasn't.

"It seems to me that we as a society have lately been caught in this false dichotomy where it's either God as the guy with the beard on the cloud or nothing at all," neuroscientist David Eagleman told Discovery News.

Staunch atheists often falsely characterize followers of religion as being "all-in" with their beliefs, opining that they ascribe to the whole creationist, woo-y shebang. "Where's your evidence?" atheists mockingly question. "You can't prove that God exists!" they accuse (correctly). Yet, hypocritically, strict atheists are guilty of the exact same crime: belief without evidence.

"We know too little to commit to a position of strict atheism. [But] we know way too much to commit to any particular religious story," Eagleman said.

Just as it's a leap of faith for a religious person to assert that God incontrovertibly exists, it's an equally large leap for a strict atheist to declare, without question, that God does not exist. As Carl Sagan eloquently explained:

An atheist is someone who is certain that God does not exist, someone who has compelling evidence against the existence of God. I know of no such compelling evidence. Because God can be relegated to remote times and places and to ultimate causes, we would have to know a great deal more about the universe than we do now to be sure that no such God exists. To be certain of the existence of God and to be certain of the nonexistence of God seem to me to be the confident extremes in a subject so riddled with doubt and uncertainty as to inspire very little confidence indeed.

Absence of evidence is not evidence of absence. As this statement applies to science, so does it apply to religion. History is replete with signs that an all-powerful deity may not exist, but such substantiation is nowhere near tantamount to proof -- especially, as Albert Einstein said, in a universe as incomprehensibly vast as our own:

The human mind, no matter how highly trained, cannot grasp the universe. We are in the position of a little child, entering a huge library whose walls are covered to the ceiling with books in many different tongues. The child knows that someone must have written those books. It does not know who or how. It does not understand the languages in which they are written. The child notes a definite plan in the arrangement of the books, a mysterious order, which it does not comprehend, but only dimly suspects. That, it seems to me, is the attitude of the human mind, even the greatest and most cultured, toward God. We see a universe marvelously arranged, obeying certain laws, but we understand the laws only dimly.

Ultimately, the key is not to be swayed to one extreme or the other -- fundamentalist religion or strict atheism -- but to walk a reasoned middle path. Eagleman believes that path is "possibilianism," the concept of holding multiple beliefs or hypotheses whilst exploring new ideas.

"The goal is to avoid committing to any particular story," Eagleman told Discovery News, "whether that's religious fundamentalism or strict atheism. The goal of possibilianism is to retain the wonder that drives us all into science in the first place and to avoid acting as though we know the answers to things we can't possibly know at the moment."

Strict atheists do the world an incredible service by promoting the scientific method, skepticism, and critical thinking. But they do a disservice by campaigning against religion or touting -- as pure truth -- the non-existence of God, for those actions (especially the latter) are just as unscientific as a blind belief in all aspects of religion.

This summer, a worldwide poll showed that atheism is on the rise and religiosity is on the decline. It is my hope that these "New Atheists" and agnostics won't narrowly focus on denigrating religion, but will instead focus on encouraging open-mindedness and discouraging fundamentalism.

That would surely make the world a more enlightened place.

There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy.

—Hamlet Act 1, Scene 5

We live in a world driven by the gods of economics, technology and science. Particularly in a time of economic austerity, it is tempting to see the arts or humanities as an optional “extra”—a happy by-product of those true engines of society when they are running smoothly. But in this article we will look at how a biblically informed worldview might turn this perspective on its head, and what the humanities might have to tell us about the present contours of the science and faith conversation.

In his iconic 1959 Rede lecture, “The Two Cultures,” CP Snow noted the dysfunctional relationship between science and the humanities, arguing that the situation is principally the result of our educational system in the West. Ken Arnold, from the medicine and arts focused Wellcome Collection in London, believes that the split continues today, but with the further extension that

In emerging countries . . . amongst the middle classes there is a strong pressure to join the ranks of doctors and scientists and engineers because they see that as the place where future economies are growing. . . . In some ways you could almost begin to feel sorry for the arts and the humanities because they seem to be worth less than the sciences.¹

Is Protestant Christianity also peculiarly prone to such thinking? A skepticism of art in religious spaces as a result of iconoclasm and the reformation, combined with a proud history of the protestant work ethic, economic success, and a profound influence on the history of science, might lead Protestants to be more inclined towards the sciences and technology than to the arts. However, there are more corrosive reasons that science has usurped the humanities in our culture than merely educational or theological bias.

In the early 20th century, logical positivists regarded the humanities as expressions merely of our inner states and desires, but having nothing to do with objective reality. Such imperialistic claims to knowledge denied that other knowledge claims referred to any true reality, and were therefore not really forms of knowledge at all. Bertrand Russell writes,

But if there is a world which is not physical, or not in space-time, it may have a structure which we can never hope to express or to know … Perhaps that is why we know so much physics and so little of anything else.²

Christian scientists are of course very sensitive to this, and work hard to explain that science cannot answer questions of ultimate meaning or the existence of God, which are beyond the scope of science. Often, this line of thinking can be narrow in focus, delineating the limits of the science, and naming those assumptions made by science that cannot be justified empirically. Such arguments can be very fruitful within this narrow context, but we should not be led into thinking that our true perception of reality is limited to such analytic and evidential approaches. There are fields of inquiry that science isn’t able to explain (such as metaphysical judgments, ethics, and beauty), and even our confidence in mathematics— upon which so much of science itself is based—rests upon assumptions that cannot be experimentally demonstrated.

The human condition

Mathematics and the sciences do seem to provide tools by which we are able to perceive the external world and its regularities. However, the arts and humanities, too, are a way of understanding reality, and they tell us less about external reality than the internal human condition. The problem is that the ‘human condition’ seems to have been relegated by many to the realm of mere desire and subjective feeling and, therefore, not reality.

The modernist account of science is that, through our reason, we are somehow able to get outside of nature and describe it objectively. The biblical account, though, has human beings as part of the created order, and so embedded in nature—made from the dust of the earth. Given that, human thought life is also part of the natural world, even despite the fact that it is not best described by the sciences.

The works of Shakespeare, for instance, are part of the created order, as are the poems of Wordsworth, the sculptures of Michaelangelo, and the music of Bach, not to mention children’s nursery rhymes, home decoration, and humming tunes whilst waiting for the bus. As C. S. Lewis wrote, "This is not panache, it is our nature." ³

A little reflection on life reveals something very strange going on here. Somehow, the mythic ‘war’ between science and religion has become the dominant battleground for defending the Christian faith, and competing explanations of the material world are used as apologetic weapons. But the reality is that science plays a peripheral role in our experience of life, not least our life as Christians. Of course that is not to deny the enormous impact of science on the material conditions of our lives, or the prevalence of the products of science. Instead, it is to observe that science plays a facilitatatory role, enabling us to carry out the real core business of our lives, which does not revolve around science. Cars, trains and airplanes are modes of transport to take us to work, or to see family, or go on holiday. Social media provide another way of being in relationship with people. Health services are not an end in themselves, but aim to make people well, so that they can get on with their lives. Why then, when life is not about science, does science dominate our way of thinking about life?

In focusing so much energy on opposing positivism are we not being inadvertently drawn into a positivist way of thinking, that science and material explanations of things are, indeed, our basic reality, what is ultimately true?

A biblical model

“We feel,” wrote the philosopher Ludwig Wittgenstein, “that even when all possible scientific questions have been answered, the problems of life remain completely untouched.” ⁴ Likewise, philosopher Susanne Langer questions any philosophy which claims to be able to explain everything:

Philosophers in every age have attempted to give an account of as much experience as they could. Some have indeed pretended that what they could not explain did not exist; but all the great philosophers have allowed for more than they could explain, and have, therefore, signed beforehand, if not dated, the death-warrant of their philosophies.⁵

Fortunately, the Bible preserves us from total positivist oblivion. There are a great many types of literature represented in the Bible, with the notable exception of scientific writing. If we long to be able to express our deepest emotions, we have the psalms; if we are looking for wise advice, we have the proverbs; if philosophical reflection, Ecclesiastes. There is poetry, song, history, biography, but there is no science. In addition, the Bible refers to the use of the visual arts in, for example, the designs of the tabernacle and temple. The Bible does seem to think the arts and humanities are fundamental for human life, but it doesn’t seem to think that what we think the physical world is constructed of matters much at all.

Do we sometimes read the Bible more like a science textbook than a novel or a poem? Most will agree that each type of literature needs to be read in its own way, but lip-service to that idea notwithstanding, recent arguments prove that it is still possible to read a poem with a scientific mentality—looking out for the ‘facts.’ Is that because we have too high a view of science, or because we have too low a view of the humanities? To say something is poetic is not to declare it ultimately untrue, futile and meaningless—it is to say it is more profound and meaningful and true than many other modes of expression.

According to Langer, part of the problem is the priority that has been accorded to discursive language as the only valid way we have of representing reality to each other. She observes that a study of symbolism shows us that this is actually only one way humans use to abstract from reality, and in fact, the situation even with discursive language isn’t as simple as has been made out. She notes that our sensory organs mediate our perceptions of the world and are already on the job— formulating, framing the world to us—before our cognitive apparatus gets to work. It must be so, or we would not be able to evaluate the importance of the vast array of sensory data we receive and reality would appear as a blur.

A linguistic symbol carries a concept we associate with it, which in turn denotes a reality. In language there is a commonly agreed definition for each word we use, thus enabling communication. But each person also has associations unique to him or her which color any particular concept. Though such personal associations with words are present all at once, they can only be expressed and communicated one at a time, because language is also sequential.

A picture also acts symbolically, though in a different way. Even something as ‘realistic’ as a photograph is likewise a representation of reality and not the reality itself. It also carries with it layers of meaning which reflect the subjective intentions of the person who took the photograph, and opens up for interpretations and associations of the person ‘reading’ the picture. A picture, though, is not sequential. All the information comes at once, and individual blotches of color carry no significance on their own, but only as part of the whole.

No amount of words could ever describe a picture in full. The number of blotches of color and their relations to each other are vast in their complexity, and one could never read words quickly enough to carry the meaning a picture brings in an instant, even if it warrants a far longer period of contemplation. Indeed, though we are only speaking here of visual perception, the same is true of our other sensory inputs, too: they all carry knowledge in quite distinct and profound ways, whilst we, in line with the Greeks, have tended to give sight a special place as the most ‘objective’ of our senses.

As we dig down into empirical science and explore the mechanisms by which sights and sounds and textures are transmitted and processed by the brain, we discover that the meaning of the sense-data which we perceive and which we attempt to describe is likewise profoundly limited by the use of words—much less mathematics—and that our science, as such, represents a tiny fraction of reality.

To suggest, then, that science is the only true way of representing reality—as positivism has done—or to exclude the humanities from our world, leaves us without a proper or even adequate means of expressing the significance we attach to even the most mundane day-to-day activities. Science is very good at describing the regularities of the physical world, but the experience of being human is no less part of the real natural world than are the structure of proteins or the movement of planets, and science does not have the appropriate tools to explore our inner worlds.

Nowadays it seems that Christian cultural life has also too-often failed to fully acknowledge other ways of representing reality than materialist science—ironic because this state of affairs is so at odds with the Bible’s model of using the arts and humanities to profoundly explore the human condition. Perhaps it is time to recover that side of the biblical witness, and remind ourselves that there are more ways of representing the world to each other than positivism has ever dreamt.

Notes

1. BBC Radio 4, “The Life Scientific”, Tuesday 25th September 2012.
2. Bertrand Russell, “Philosophy”, New York. W.W.Norton &Co, 1927, page 265, quoted by Susanne K. Langer, Philosophy in a New Key, Harvard University Press, 1979, page 88.
3. C. S. Lewis, “Learning in War Time” in Fernseed and Elephants and other Essays on Christianity, Fontana, 1975, page 28.
4. Ludwig Wittgenstein, Tractatus Logico-Philosophicus. Routledge and Kegan Paul, 1951, page 187.
5. Susanne K. Langer, Philosophy in a New Key: A Study in the Symbolism of Reason, Rite and Art. Harvard University Press, 1979, p 5.

In 1774, the French chemist Antoine Lavoisier replicated the relevant experiments in more controlled ways to demonstrate that mass was conserved during combustion. He also renamed the part of the air that burned 'oxygène.' English scientists resisted the French scientist's new name, not least because the English Priestly had already published his discovery of the gas. 'Oxygen' nonetheless entered the common English vocabulary in part due to one of the first popular science books, The Botanic Garden (1791), which included a poem praising the gas using the preferred French name. By coincidence, this book also promoted some early ideas about biological evolution (specifically, it suggested that sexual reproduction might be important to evolution, which might help to explain the popularity of a book of poems about science). It was written by Erasmus Darwin, the grandfather of Charles Darwin, who first proposed the modern form of the theory of biological evolution in his 1859 book, On the Origin of Species.

150 years later, we are discovering that the lines connecting evolution and oxygen run deeper than the Darwin family tree. We now know, for instance, that for roughly half of the Earth's 4.6-billion-years of history, there was little to no oxygen in the atmosphere. Instead, oxygen entered the atmosphere in two major pulses, with one between 2.4 and 2.2 billion years ago, and another between 0.8 and 0.54 billion years ago. Recent evidence suggests that the first pulse may have actually been the largest event in a series of fits and starts beginning at around 2.7 billion years ago that finally produced a stable low oxygen atmosphere by around 1.8 billion years ago.

Remarkably, both episodes of atmospheric oxygenation happened just before explosions in biological diversity. We have spotty evidence of unicellular eukaryotes (cells with nuclei) before 2.4 billion years ago, but the first fossil evidence for large, diverse eukaryotic communities comes at 1.5 billion years ago. If you are a human, this is part of your history; humans are multicellular eukaryotes descended from one of these early unicellular pioneers. Multicellular animal life is an innovation that seems to have required more oxygen: animals don't appear in the fossil record until about 0.61 billion years ago, toward the end of the second pulse of oxygen.

It is, perhaps, not surprising that major evolutionary events in the eukaryotic family tree, including the origin and diversification of the animals, would be tied to or even driven by major changes in atmospheric oxygen abundance. Eukaryotes generally, and animals specifically, are oxygen lovers. As the subjects of Mayow and Priestly died to prove, we require oxygen for respiration. In general, the larger and more organizationally complex we are (for instance, a human versus a slime mold), the more oxygen we require.

But where did all the oxygen come from? Ultimately, it was produced by the bacterial equivalents of the plants in Joseph Priestley's experiment, a group of photosynthetic microbes called the cyanobacteria. These bacteria are the first and only organisms to have evolved the ability to produce oxygen by photosynthesis. In fact, plants are able to photosynthesize only because their cells harbor descendants of one of the early cyanobacteria. We call them chloroplasts and think of them as little cellular organs, but they are actually the great-great-great... granddaughters of a cyanobacterium that long ago gave up its independence in exchange for the stable environment inside a eukaryotic cell. In any case, photosynthesis is the only known geological process capable of producing oxygen at the rates required for the two pulses of atmospheric oxygenation. The first pulse was probably largely accomplished by cyanobacteria, while the second pulse was probably mostly associated with the cyanobacterial denizens of eukaryotic algae.

What is remarkable about all of this is the extent to which modern life and the atmosphere are products of each other's evolution. The tiniest of photosynthetic organisms played one of the most important roles in shaping the sky, and the sky helped to usher in the age of animals! As a Christian and a geobiologist, I do not believe that this relationship is anticipated or predicted by the Biblical creation accounts.

But then again, why should it have been? The original audience for these accounts would have found concepts like bacteria or even oxygen incomprehensible. The people for whom the Bible was originally addressed thought about origins primarily in terms of ongoing national conflicts and the current human condition. Faced with a variety of violent creation myths that reinforced national conflicts, Genesis said that the universe was created to be good, peaceful, and orderly by one god. It specifically listed things worshipped by other nations as creatures of that god, and in the climax of the creation account, Abraham was called by the same god to be a blessing to all the nations through Israel.

I am not claiming that the Bible cannot be read in a way that can shape us in real and meaningful ways today. In fact, for those who believe that the Bible is inspired, part of the meaning of inspiration has to be that the Bible is God's powerful word to both those with no concept of modern science (most of the world's population, both today and in the past) and to those deeply engaged in its practice. But, and this is a big but, we contemporary Americans read the Bible best when we are sensitive to the assumptions of the original audience, carefully observe how the Bible transformed those assumptions, and look for opportunities to do the same thing with our thinking.

I think that it is important for Christians to reflect on the view of origins that science has given us in light of the thinking evident in the Biblical creation accounts. We have to do this because science gives us a story that is inherently without philosophical or theological meaning; it is up to us to give it meaning by understanding it in relationship with our beliefs. For instance, some see the evolutionary history of life and the Earth and give that history meaning by elevating chance and necessity to the level of prime actors in their own modern creation account. This meaning is not inherent to the theory of evolution; it is supplied by an atheistic belief system external to the theory. I suggest that this view mistakes created things (chance and necessity) for the Creator.

Others have preferred to see the regularity of the universe as the action of an orderly God. This is an old approach to natural theology that was popular among many early scientists, and saw God as responsible for doing such things as maintaining the planets in consistent paths around the sun. Still others look for God in the unexplained. This is a newer approach that sees God as acting primarily in short bursts not explainable by the regular, orderly function of the universe. Looking for God in these ways is a little like trying to capture him in a bell jar, an approach that worked perfectly well with oxygen for Mayow, Priestley, and Lavoisier, but one that is unlikely to impress the Creator described in the Bible.

I prefer to see the same history in the light of a God who desires to share aspects of his nature with his creation, notably including his creativity. Just as he has made humans to be creators (with a little 'c'), he has given the rest of our world the gift of being instrumental in its own creation through the process of evolution. This surely must have been part of what God saw when he described his creation as good! It is my hope that the modern American church can learn to see the goodness of creation in things like the evolutionary history of life and the atmosphere, as well.

This post first appeared in October 2009

There are several different kinds of arguments that people bring along these lines; I want to talk about just one. So first… the Heidelberg catechism, one of the forms of unity of the church I go to (the Christian Reformed Church), says

Providence is the almighty and ever-present power of God, by which he upholds as with his hand heaven and Earth and all creatures and so rules them, that leaf and blade, rain and drought, fruitful and lean years, food and drink, health and sickness, prosperity and poverty. All things, in fact, come to us not by chance, but from his fatherly hand.

And part of the way it comes to us—not by chance, but from his fatherly hand—part of the way God has designed our world, is that there is a great deal of regularity and dependability in our world. Of course, if it were not for this regularity and dependability, we couldn’t do the things that we actually do. I mean, for example, if I just wanted to walk off the stage—if, for example, all the sudden those stairs over there suddenly turned into a ladder going up—well, that would make it really difficult.

If you are trying to build a house, for example, you have this hammer, but all the sudden the hammer turns in to a goose or a pigeon. Again, that would make things really difficult…or if the nail turned into a worm…or if you get in the car and turn the key and the car turns into a camel, things would be really hard, much harder than they are. This regularity and dependability in our world is an essential condition of our being able to live in the world in which we actually do.

If the world were irregular enough, we would not even be able to live in it, but there are also, according to classical Christianity here (the Heidelberg catechism, for example) there are also special divine actions; sometimes God does things specially. There are miracles in Scripture: the parting of the Red Sea, for example, Jesus walking on water, Jesus changing water into wine. There are miraculous healings: Jesus rising from the dead, Jesus raising Lazarus from the dead, and so on. And according to classical Christians, many of them, perhaps most of them, are special divine actions. God, for example, responds to prayers. He works in the hearts and minds of his children to effect sanctification. There is, what Calvin called, the internal testimony or witness of the Holy Spirit, and there is what Thomas Aquinas called the internal instigation of the Holy Spirit. So, these things are all special actions on the part of God. God constantly causes events in the world. Ok, so far fair enough—what is the problem?

Many theologians seem to think there is a science-religion problem here. I don’t think any of the theologians of Biola think this, (I don’t know, but I doubt it) but many theologians do. For example, Rudolf Bultmann says, “The historical method,” which of course he thinks that is the method we should use, “includes the presupposition that history is a unity in the sense of a closed continuum of effects in which individual events are connected by the succession of cause and effect. This continuum, furthermore, cannot be rent by the interference of supernatural, transcendent powers.”

That’s what he says. Alright, there is this continuum that cannot be rent by the interference of supernatural (that would be God) or transcendent powers. So, it is a little bit like the laws of the Medes and Persians. You probably remember Daniel. Daniel was a favorite of King Darius, and well, the other courtiers became jealous of Daniel (they didn’t like it that the king liked him so well). So, they came to the king and said, “Oh king, live forever, we think it would be a great idea if you passed an edict to the effect that you alone can be worshipped. Everybody has to worship you and nothing else.” Well the king thought that over for a minute, and that sounded pretty good to him so he said, “I guess that it is a pretty good idea.” So he made this edict; he made this declaration: “Only King Darius is to be worshipped—no one else, nothing else.”

These courtiers knew that Daniel worshipped God, and they thought probably Daniel would keep right on worshipping God despite this edict. So they were watching Daniel, and he was, in fact, worshipping God. So they came to the king. Now the penalty for worshipping something else was to be thrown into the lion’s den and they said, “Well, king live forever, looks like Daniel has been violating this edict. You have got to throw him in the lion’s den.”

Well, the king didn’t want to do this because he really liked Daniel. He thought this was a miserable way to proceed, and he didn’t want to do it, but then they said to him, “O king live forever, and remember a law of the Medes and Persians cannot be abrogated, even by the king himself.” So once it’s put in place, not even the king himself can change it or abrogate it or go against it.

That is sort of the suggestion that you get here from Bultmann. Bultmann thinks, “Maybe God created the world and set it up in a certain way, but once he did that, not even he can interfere in it”—he uses that word interference—“not even he can do anything in it. He just has to keep hands off.” It is like the law of the Medes and the Persians.

Another theologian who agrees is John Macquarrie, who says,

The way of understanding miracle (and that would be one kind of special divine action) that appeals to breaks in the natural order and to supernatural intervention belongs to the mythological outlook, and cannot commend itself in a post-mythological climate of thought. The traditional conception of miracle is irreconcilable with our modern understanding of both science and history. Science proceeds on the assumption that whatever events occur in the world, can be accounted for in terms of other events that also belong within the world, and if on some occasion, we are unable to give a complete account of some happening, the scientific conviction is that further research will bring to light further factors in the situation that will turn out to be just as imminent and this worldly as the factors already known.

Ok again, no room there for special action. And the third thinker here, Langdon Gilkey (still another theologian), says something similar, but I will pass. I will not read that one in the interest of saving a little bit of time, but these three theologians, plus many others want to assert that there is something wrong with the idea of God acting in the world, acting in the world in a way that goes beyond creation and sustaining, or creation and holding things in existence. So they think, “Ok, God created the world; God sustains it in existence”…that is ok with them, but anything beyond that, God performing any miracles, raising Jesus from the dead, or for that matter working in somebody’s heart and mind in a special way, that, they say, is a real problem. The question is, what is the problem?

Well, the next little bit here…according to the Christian and theistic idea, God is a person; he has knowledge, loves, and hates. He has aims and ends. He acts on the basis of his knowledge to achieve his ends. He is all-powerful, all-knowing, and wholly good. Thirdly (noted above by the Heidelberg catechism), God has created the world. Fourth is God conserves and sustains and maintains in being this world he created, but fifth, at least sometimes, God acts in a way going beyond creation and conservation in miracles, but also in his providential guiding of history, his working in the hearts of people, his internal instigation of the Holy Spirit, and so on, and it is with that fifth category that these people have a problem. It is God’s special action in the world—action beyond conservation and creation—and miracles would be an example.

So we might think of these theologians as endorsing what we could call hands off theology. God has got to keep his hands off. God could create the world. God conserves the world, sustains it in being, but he can’t do anything else—that is as far as he could go. It is hands off theology, and Bultmann, even in this context, even talks about interfering. I mean if God did something in the world that would be interfering, which, when you think about it, is a sort of strange thing to say—I mean if God created the world, he is the omnipotent, omniscient, holy, good creator of the world—when you accuse someone of interfering, you are saying they are doing something they should not be doing, right?

So Bultmann thinks if God did something in the world that would be interfering, and he should be ashamed of himself. Ok, now why is this a problem? Their suggestion is that somehow it is contrary to science. It is contrary to science the suggestion that God acts specially in the world. I didn’t read that bit, but Gilkey says, "The causal nexus in space and time which the enlightenment science and philosophy introduced into the western mind is also assumed by modern theologians and scholars. Since they participate in the modern world of science, both intellectually and existentially, they can scarcely do anything else.”

From a presentation sponsored by Biola University’s Center for Christian Thought, and delivered February 12, 2012 at EV Free Church, Fullerton, CA. Used by permission.

In his essay for that series, Jeff Schloss addressed the question of whether animal death is a natural evil, but also noted that such theological considerations aside, death does not actually “drive evolution” in the way most people imagine—especially when they think of violence in the natural world. This more complicated sense of death’s role is partially the result of modern evolutionary science recognizing the importance of cooperation and inter-relation among species, rather than just direct competition. But just as important is the knowledge that evolution is significantly shaped not by the deaths of individual creatures, but by extinction, the loss of species over time. In this post, we explore some aspects of how extinction acts as both a destructive and creative force in evolutionary history, including the evolutionary history of mammals.

Sporadic extinction

Extinction is actually a common feature of life on earth when viewed over long (e.g. geological) timescales. By some estimates, over 99% of the species that have ever lived have gone extinct. One factor that promotes extinction is the fact that evolution does not produce species that are optimally adapted to their environment, but only better adapted than their local competitors. Invasive species testify to this fact: local (endemic) species are not always the best-adapted species for their own environment. Examples abound where species from other environments are actually better-suited to out-compete endemic species. Here in my own province, the invasive Himilayan blackberry (Rubis discolor) easily outcompetes many endemic species. If endemic species were optimally adapted to their environment, this would not be possible, as they would outcompete all exotic species. Instead, exotic species, by chance, might be better adapted to an ecosystem they did not evolve in. These exotics may be capable of eliminating endemic species altogether.

Such an extinction event (of a single species, or perhaps a handful of species) alters the environment of other remaining species in an ecosystem. This, in turn, may influence the ability of some of these remaining species to reproduce compared to other species. For example, the extinction of a competitor might allow a species to increase in population size. Conversely, the extinction of a species that provides a benefit (such as a pollinator) may reduce a species in number. As the ecosystem landscape shifts due to loss of species, new biological opportunities, or niches, might arise. These new niches are then available to support new species to fill them.

Extinction, en masse

One way to appreciate how extinction opens up new niches is to examine mass extinction events – geologically brief periods where large numbers of species go extinct at the same time. Over the history of life on our planet there have been several mass extinction events. The largest such event, at the end of the Permian (~250 million years ago) appears to have been caused, at least in part, by intense volcanic activity over several hundred thousand years. This activity likely shifted CO2 levels and eventually led to a “runaway” greenhouse effect that dramatically raised global temperatures and led to anoxic (i.e. oxygen-depleted) oceans, though the exact contributions of these varied factors remains an area of scientific debate. What appears certain is that during this period environmental changes were too rapid for most species to keep evolutionary pace with, and as a result over 90% of the world’s species alive at that time went extinct. Obviously this represents destruction of biodiversity on an unimaginable scale, and the destructive effects of this event are with us to this day.

Speciation, en masse

This destruction, however, is not the whole story. Following on from the Permian mass extinction, we observe a steady increase in new species. These are species previously unknown in the fossil record. In fact, this pattern (a “radiation” of new species following an extinction event) is the rule, not an exception – we see the same effect after every mass extinction in the fossil record. Extinction is a driving force for novelty.

Perhaps the most famous mass extinction event is the Cretaceous – Paleogene (KPg) extinction, and it too follows this standard pattern. This mass extinction took place 65 million years ago when an asteroid ~10 kilometers in diameter struck the Yucatan peninsula. (Note: this event was formerly known as the Cretaceous – Tertiary (K-T) extinction, but that terminology is in decline within the scientific community). This extinction event is famous since it is the one that eliminated the dinosaurs (with the exception of the ancestors of modern birds). As with the Permian extinction, the elimination of so many species shifted the evolutionary landscape for the remaining species, and the result was a burst of speciation that appears rapid when viewed in geological time. Significantly for our own species, following the KPg extinction event is a burst in mammalian speciation, as small mammals that survived the event diverge and fill niches left empty by the dinosaurs. Without this event, the trajectory of mammalian evolution would certainly look very different.

Clearing the deck, and re-filling the niches

One interesting fact to note is that biological features that make a species resistant to usual, sporadic extinction are not necessarily the same features that will be useful during a mass extinction event. While species are continually under selection at the local level, there is no mechanism for (pre) selection to survive a mass extinction. As such, only species that happen to have the right combination of traits will survive, and often spread widely after a mass extinction. These so-called “disaster species” are usually generalists, and will later be displaced by more specialized species as they arise. As such, where sporadic extinction allows for more gradual turnover in species, mass extinction events are major “resets” of evolution that can radically shift what constitutes “well adapted” in a geological eyeblink. For mammals at the KPg boundary, small body size and an omnivorous diet (including the ability to scavenge detritus) were the “winning” combination of traits that allowed them to survive where larger, more specialized animals (think Tyrannosaurus rex) could not. From this rather humble station, mammals would come to dominate the world’s ecosystems over the coming eons – including a lineage that would someday lead to our own species. Far from only a destructive force, extinction is a powerful mechanism to allow evolutionary innovation, and one that was of significant importance to us.

For further reading:

Meredith, R.W. et al (2011). Impacts of the Cretaceous Terrestrial Revolution and KPg Extinction on Mammal Diversification. Science 334; 521-524.

Fastovsky, D.E. (2005). The Extinction of the Dinosaurs in North America. GSA Today (15); 1052-5173.

Benton, M.J. and Twitchett, R.J. (2003). How to kill (almost) all life: the end-Permian extinction event. TRENDS in Ecology and Evolution (18); 358-365.

There are two opposite errors which need to be countered about the fossil record: 1) that it is so incomplete as to be of no value in interpreting patterns and trends in the history of life, and 2) that it is so good that we should expect a relatively complete record of the details of evolutionary transitions within all or most lineages.

What then is the quality of the fossil record? It can be confidently stated that only a very small fraction of the species that once lived on Earth have been preserved in the rock record and subsequently discovered and described by science.

There is an entire field of scientific research referred to as "taphonomy" -- literally, "the study of death." Taphonomic research includes investigating those processes active from the time of death of an organism until its final burial by sediment. These processes include decomposition, scavenging, mechanical destruction, transportation, and chemical dissolution and alteration. The ways in which the remains of organisms are subsequently mechanically and chemically altered after burial are also examined -- including the various processes of fossilization. Burial and "fossilization" of an organism's remains in no way guarantees its ultimate preservation as a fossil. Processes such as dissolution and recrystallization can remove all record of fossils from the rock. What we collect as fossils are thus the "lucky" organisms that have avoided the wide spectrum of destructive pre- and post-depositional processes arrayed against them.

Soft-bodied organisms, and organisms with non-mineralized skeletons have very little chance of preservation under most environmental conditions. Until the Cambrian nearly all organisms were soft-bodied, and even today the majority of species in marine communities are soft-bodied. The discovery of new soft-bodied fossil localities is always met with great enthusiasm. These localities typically turn up new species with unusual morphologies, and new higher taxa can be erected on the basis of a few specimens! Such localities are also erratically and widely spaced geographically and in geologic time.

Even those organisms with preservable hard parts are unlikely to be preserved under "normal" conditions. Studies of the fate of clam shells in shallow coastal waters reveal that shells are rapidly destroyed by scavenging, boring, chemical dissolution and breakage. Occasional burial during major storm events is one process that favors the incorporation of shells into the sedimentary record, and their ultimate preservation as fossils. Getting terrestrial vertebrate material into the fossil record is even more difficult. The terrestrial environment is a very destructive one: with decomposition and scavenging together with physical and chemical destruction by weathering.

The potential for fossil preservation varies dramatically from environment to environment. Preservation is enhanced under conditions that limit destructive physical and biological processes. Thus marine and fresh water environments with low oxygen levels, high salinities, or relatively high rates of sediment deposition favor preservation. Similarly, in some environments biochemical conditions can favor the early mineralization of skeletons and even soft tissues by a variety of compounds (eg. carbonate, silica, pyrite, and phosphate). The likelihood of preservation is thus highly variable. As a result, the fossil record is biased toward sampling the biota of certain types of environments, and against sampling the biota of others.

In addition to these preservational biases, the erosion, deformation and metamorphism of originally fossiliferous sedimentary rock have eliminated significant portions of the fossil record over geologic time. Furthermore, much of the fossil-bearing sedimentary record is hidden in the subsurface, or located in poorly accessible or little studied geographic areas. For these reasons, of those once-living species actually preserved in the fossil record, only a small portion have been discovered and described by science. However, there is also the promise of continued new and important discovery.

The forces arrayed against fossil preservation also guarantee that the earliest fossils known for a given animal group will always date to some time after that group first evolved. The fossil record always provides only minimum ages for the first appearance of organisms.

Because of the biases of the fossil record, the most abundant and geographically widespread species of hardpart-bearing organisms would tend to be best represented. Also, short-lived species that belonged to rapidly evolving lines of descent are less likely to be preserved than long-lived stable species. Because evolutionary change is probably most rapid within small isolated populations, a detailed species-by-species record of such evolutionary transitions is unlikely to be preserved. Furthermore, capturing such evolutionary events in the fossil record requires the fortuitous sampling of the particular geographic locality where the changes occurred.

Using the model of a branching tree of life, the expectation is for the preservation of isolated branches on an originally very bushy evolutionary tree. A few of these branches (lines of descent) would be fairly complete, while most are reconstructed with only very fragmentary evidence. As a result, the large-scale patterns of evolutionary history can generally be better discerned than the population-by-population or species-by-species transitions. Evolutionary trends over longer periods of time and across greater anatomical transitions can be followed by reconstructing the sequences in which anatomical features were acquired within an evolving branch of the tree of life.

Judging from the flurry of headlines over the past week, one might be tempted to think that proof positive of God’s existence (or lack thereof) had just appeared out of a 27-km-tunnel buried beneath the Swiss-French border. This frenzy of news headlines and blog titles hailed the recent news that CERN’s Large Hadron Collider has discovered a brand new particle of a mass of 125-126 GeV, which is assumed to be the Higgs boson, or the so-called “God particle.” The discovery of the Higgs boson would certainly be a breakthrough for particle physics and cosmology, but would such a finding also radically redefine theology’s understanding of God or challenge the existence of such a deity? Is there actually any theological or religious significance in Higgs physics at all?

The short answer is “no,” which becomes apparent when one considers the widely-reported story of how it got named. In 1993, Nobel Laureate physicist Leon Lederman, along with science writer Dick Teresi, wrote a book detailing the history of particle physics starting with Pre-Socratic Greek philosophy Democritus and culminating with the hunt for the Higgs boson. Until this latest discovery, the Higgs boson was the elusive final missing piece of the puzzle known as the Standard Model—a collection of the fundamental particles that constitute our universe and the complex and mathematically-sophisticated relationships between them. Considering how incredibly difficult finding the Higgs boson was proving to be, Lederman wanted to name the book after that “goddamn particle,” according to some of his collaborators. His editor, however, would not allow it and so the name was shortened to “The God Particle: If the Universe Is the Answer, What is the Question?” And thus ‘the God particle’ was born, carrying with it more than enough social baggage for such a miniscule particle.

Particle physicist Dr. Zosia Krusberg (at right) is visiting assistant professor of physics and astronomy at Vassar College and thinks “the term ‘god particle’ is unfortunate. The Higgs boson is no more (or less) divine or spiritually significant than any other elementary particle within the standard model of particle physics.” It may be fundamental to explaining one of the most basic characteristics of the universe—namely the existence of matter and mass in addition to energy—but “it is no more (or less) important than any other physics principle underlying the Standard Model.”

Last week’s discovery was monumental in that it may have finally provided experimental evidence for the Higgs Mechanism and defined the specific energy of the resulting Higgs boson, but even this “breakthrough” for particle physics leaves many scientific questions unresolved. Finding the Higgs boson completes the Standard Model, but it does not do away with many other questions and shortcomings of the current state of particle physics, such as the constituent particles of dark matter, a quantum theory of gravity, and other “mathematically subtle problems.” Not to mention that there is still significant work to be done to determine the exact nature of this newly-found particle. According to Dr. Krusberg, this particle might behave just as the Standard Model predicts or it could instead be “a Higgs-like particle that will serve as a gateway into explorations of physics beyond the Standard Model." Krusberg continued, “And I guarantee that it is this latter scenario that most of us are hoping for: physicists love nothing more than discovering the shortcomings of their theories, since this is the first step toward more fundamental theories with even more predictive power!”

No, finding the Higgs boson does not answer all the questions of particle physics, much less lend insight into the existence (or not) of God. For that reason, Dr. Krusberg (like most physicists) bemoans the term ‘God particle’ and insists, “There really is nothing either literally or metaphorically god-like about the Higgs boson.” Indeed, one writer for the British journal The Guardian reached such a point of frustration about the name that he ran a competition for alternatives. The winner was “the champagne flute boson,” ostensibly because the bottom of a champagne bottle is an excellent and oft-used demonstration of the energy potential of the Higgs Mechanism. Or then again, perhaps it is simply because physicists thought that finally finding this shy particle would call for some of the bubbly.

On the other hand, some science writers and scientists can appreciate the ‘educational benefits’ of such a mysterious and controversial name because it attracts the attention of the general public and puts a relatable face on an extremely esoteric physics concept. Krusberg herself admits that “People are naturally drawn to the mysterious and the controversial, providing educators with great teaching opportunities.” But she worries about the larger social implications involved in “mixing the vernacular of physics and spirituality,” not least because such uncritical mixing can lead the non-scientific community to draw conclusions about the authority and reach of science that are not justified.

Understanding that the Higgs boson is not the literal stuff of God and that it does not prove or disprove God’s existence (as the name seems to suggest) extinguishes the fire under any sort of religious outcry. But this does not mean that its discovery is irrelevant to the discussion of science and faith, nor to the Christian community as a whole. As Dr. Krusberg remarks, “The recent discovery of [this] new boson at the LHC perfectly embodies the scientific process at its best (and thereby illustrates to the public why and how science works).” Scientific exploration of nature is not a fool-proof endeavor; healthy skepticism and accountability to a wide community of other researchers are absolutely critical to its success. But such evidence of the power and finesse of well-executed science as we saw last week is a testament to our ability to explore and understand the ‘how’ of the universe. God has equipped humanity with the desire, the intellectual abilities, and the collective will to recognize and explore the cosmic order and beauty of his creation. God has made our home knowable, and has given us the tools and capacities by which to know it.

At left, Cern researchers present their findings to a few hundred of their colleagues in Melbourne, Australia. Image © 2012 CERN

It is valuable, then, for the Christian community to understand and appreciate how science works, in part to recognize that there are many instances in which science and the church work in tandem in order to better understand and better serve the world. But I think there is something else we can draw from the story of the Higgs boson, too. The nickname ‘the God particle’ has touched nerves in religious communities because it implies that science has the ability to prove or disprove divine existence by physical means. Even though the physics community is by no means claiming insight into the divine, it is sometimes assumed by the religious community that scientists view their work as chipping away at God’s existence when they begin to understand something that was previously unknown, or known only “by faith” in esoteric theories and models.

And yet, regardless of motives or metaphysical interpretations, perhaps physicists' search for the Higgs boson is in fact an apt picture of our own search for God. How many times have we stared up at the starry ceiling in times of crisis and prayed fervently for some kind of sign from God to assure us of his presence? And how many times has that much-desired evidence appeared only in retrospect, when we look back to see God’s hand faithfully and elegantly working in ways inscrutable at the time? It took a community of physicists to discern the presence of the Higgs boson. But even so, they could only do so after the fact from the cascade of particle decays it sparked; they could not observe the particle itself directly. In a similar way, though we often do not see the working of God directly, “in the moment,” we still trust in his presence and providence, often depending on friends, family and the community of the church to help us see his hand in hindsight.

So while the discovery of the Higgs boson does not itself explain God, we rejoice at the subtle yet striking new insight we have into God’s creative genius via the Higgs boson and at the way God gives evidence of his faithfulness in the ordered creation itself. Perhaps, however, the greatest insight we can glean from this breakthrough is an analogy for the way God calls us to seek him and find him together, in the community of those who follow his son.

Tomorrow, Baylor University physicist Gerald Cleaver answers the question, "What is the Higgs boson?"

A scientist, my dear friends, is a man who foresees; it is because science provides the means to predict that it is useful, and the scientists are superior to all other men. --Henri de Saint-Simon¹

Scientism is a rather strange word, but for reasons that we shall see, a useful one. Though this term has been coined rather recently, it is associated with many other “isms” with long and turbulent histories: materialism, naturalism, reductionism, empiricism, and positivism. Rather than tangle with each of these concepts separately, we’ll begin with a working definition of scientism and proceed from there.

Historian Richard G. Olson defines scientism as “efforts to extend scientific ideas, methods, practices, and attitudes to matters of human social and political concern.” ² But this formulation is so broad as to render it virtually useless. Philosopher Tom Sorell offers a more precise definition: “Scientism is a matter of putting too high a value on natural science in comparison with other branches of learning or culture.” ³ MIT physicist Ian Hutchinson offers a closely related version, but more extreme: “Science, modeled on the natural sciences, is the only source of real knowledge.” ⁴ The latter two definitions are far more precise and will better help us evaluate scientism’s merit.

A History of Scientism

The roots of scientism extend as far back as early 17th century Europe, an era that came to be known as the Scientific Revolution. Up to that point, most scholars had been highly deferential to intellectual tradition, largely a combination of Judeo-Christian scripture and ancient Greek philosophy. But a torrent of new learning during the late Renaissance began to challenge the authority of the ancients, and long-established intellectual foundations began to crack. The Englishman Francis Bacon, the Frenchman Rene Descartes, and the Italian Galileo Galilei spearheaded an international movement proclaiming a new foundation for learning, one that involved careful scrutiny of nature instead of analysis of ancient texts.

Descartes and Bacon used particularly strong rhetoric to carve out space for their new methods. They claimed that by learning how the physical world worked, we could become “masters and possessors of nature.” ⁵ In doing so, humans could overcome hunger through innovations in agriculture, eliminate disease through medical research, and dramatically improve overall quality of life through technology and industry. Ultimately, science would save humans from unnecessary suffering and their self-destructive tendencies. And it promised to achieve these goals in this world, not the afterlife. It was a bold, prophetic vision.

As this new method found great success, the specter of scientism began to emerge. Both Bacon and Descartes elevated the use of reason and logic by denigrating other human faculties such as creativity, memory, and imagination. Bacon’s classification of learning demoted poetry and history to second-class status.⁶ Descartes’ rendering of the entire universe as a giant machine left little room for the arts or other forms of human expression. In one sense, the rhetoric of these visionaries opened great new vistas for intellectual inquiry. But on the other hand, it proposed a vastly narrower range of which human activities were considered worthwhile.

The Enlightenment

A century later, many of the Enlightenment intellectuals continued their love-affair with the power of natural science. They claimed that not only could science enhance the quality of human life, it could even promote moral improvement. The Encyclopedist Denis Diderot aimed to collect, organize, and preserve all human knowledge so that “our children, becoming better instructed, may become at the same time more virtuous and happy.” ⁷ Many of the French philosophes even claimed that science could be a substitute for religion. In fact, during the French Revolution, numerous Catholic churches were converted into “Temples of Reason” and held quasi-religious services for the worship of science.⁸

Positivism

The 19th century witnessed the most powerful and enduring formulation of scientism, a system called positivism. Its founder was August Comte, who built his positive philosophy from a deep commitment to David Hume’s empiricism and skepticism. Comte claimed that the only valid data is acquired through the senses. Nothing was transcendent, and nothing metaphysical could have any claim to validity.⁹ The task of scientists was twofold—first, to demonstrate how all phenomena, including human behavior, are subject to invariable natural laws.¹⁰ Second, they would reduce these natural laws to the smallest possible number, and ultimately unify them under the laws of physics.¹¹

Comte also subsumed all of human intellectual history into a single process which he called the Law of Three Stages. In his view, each branch of knowledge passes through three stages: the theological or fictitious, the metaphysical or abstract, and lastly the scientific or positive state. He believed that through the continual advancement of human understanding, religion would fade away, philosophy and the humanities would be transformed into a naturalistic basis, and all human knowledge would eventually become a product of science. Any ideas outside that realm would be pure fantasy or superstition.

Logical Positivism

Positivism did not lose its appeal in the 20th century. To the contrary, a group known collectively as The Vienna Circle reinvigorated the fundamental tenets of positivism with enhanced symbolic logic and semantic theory. They called their approach, fittingly, logical positivism. In this system, there are only two kinds of meaningful statements: analytic statements (including logic and mathematics), and empirical statements, subject to experimental verification. Anything outside of this framework is an empty concept.¹²

Given its sweeping claims, logical positivism came under heavy scrutiny. Karl Popper pointed out that few statements in science can actually be completely verified. However, a single observation has the potential to invalidate a hypothesis, and even an entire theory. Therefore, he proposed that instead of experimental verification, the principle of falsifiability should demarcate what qualified as science, and by extension, what can qualify as knowledge.¹³

Another weakness of the positivist position is its reliance on a complete distinction between theory and observation. Observations, essential to the empirical approach of science, were claimed by positivists to be brute facts which one could use to establish, evaluate, and compare the theories. However, W.O. Quine pointed out in his “Two Dogmas of Empiricism” that observations themselves are partly shaped by theory (“theory-laden”).¹⁴ What counts as an observation, how to construct an experiment, and what data you think your instruments are collecting—all require an interpretive theoretical framework. This realization does not deal a death-blow to the practice of science (as some post-modernists like to claim), but it does undermine the positivist claim that science rests entirely on facts, and is thus an indisputable foundation for knowledge.

Scientism of Today

Scientism today is alive and well, as evidenced by the statements of our celebrity scientists:

The Cosmos is all that is or ever was or ever will be. –Carl Sagan, Cosmos

The more the universe seems comprehensible, the more it also seems pointless. –Stephen Weinburg, The First Three Minutes

We can be proud as a species because, having discovered that we are alone, we owe the gods very little. –E.O. Wilson, Consilience

While these men are certainly entitled to their personal opinions and the freedom to express them, the fact that they make such bold claims in their popular science literature blurs the line between solid, evidence-based science, and rampant philosophical speculation. Whether one agrees with the sentiments of these scientists or not, the result of these public pronouncements has served to alienate a large segment of American society. And that is a serious problem, since scientific research relies heavily upon public support for its funding, and environmental policy is shaped by lawmakers who listen to their constituents. From a purely pragmatic standpoint, it would be wise to try a different approach.

Physicist Ian Hutchinson offers an insightful metaphor for the current controversies over science:

The health of science is in fact jeopardized by scientism, not promoted by it. At the very least, scientism provokes a defensive, immunological, aggressive response from other intellectual communities, in return for its own arrogance and intellectual bullyism. It taints science itself by association.¹⁵

Noting that most Americans enthusiastically welcome scientific advancements, particularly those in health care, transportation, and communications, Hutchinson suggests that perhaps what the public is rejecting is not actually science itself, but a worldview that closely aligns itself with science—scientism.¹⁶ By disentangling these two concepts, we have a much better chance for enlisting public support for scientific research than we would by trying to convince millions of people to embrace a materialistic, godless universe in which science is our only remaining hope.

Distinguishing science from scientism

So if science is distinct from scientism, what is it? Science is an activity that seeks to explore the natural world using well-established, clearly-delineated methods. Given the complexity of the universe, from the very big to very small, from inorganic to organic, there is a vast array of scientific disciplines, each with its own specific techniques. The number of different specializations is constantly increasing, leading to more questions and areas of exploration than ever before. Science expands our understanding, rather than limiting it.

Scientism, on the other hand, is a speculative worldview about the ultimate reality of the universe and its meaning. Despite the fact that there are millions of species on our planet, scientism focuses an inordinate amount of its attention on human behavior and beliefs. Rather than working within carefully constructed boundaries and methodologies established by researchers, it broadly generalizes entire fields of academic expertise and dismisses many of them as inferior. With scientism, you will regularly hear explanations that rely on words like “merely”, “only”, “simply”, or “nothing more than”. Scientism restricts human inquiry.

It is one thing to celebrate science for its achievements and remarkable ability to explain a wide variety of phenomena in the natural world. But to claim there is nothing knowable outside the scope of science would be similar to a successful fisherman saying that whatever he can't catch in his nets does not exist.¹⁷ Once you accept that science is the only source of human knowledge, you have adopted a philosophical position (scientism) that cannot be verified, or falsified, by science itself. It is, in a word, unscientific.

Notes

1. "Un savant, mes amis, est un homme qui prévoit; c’est par la raison que la science donne le moyen de prédire qu’elle est utile, et que les savants sont supérieurs à tous les autres hommes." Translated into English by Valence Ionescu in The Political Thought of Saint-Simon. Oxford University Press, 1976. Page 76
2. Olson, Richard G. Science and Scientism in Nineteenth-Century Europe. Urbana, University of Illinois Press, 2008.
3. Sorell, Tom. Scientism: Philosophy and the Infatuation with Science. New York: Routledge, 1991.
4. Hutchinson, Ian. Monopolizing Knowledge: A Scientist Refutes Religion-Denying, Reason-Destroying Scientism. Belmont, MA: Fias Publishing, 2011.
5. Descartes, Rene. Discourse on Method
6. Sorell, p176
7. Sorell, p35
8. Ozouf, Mona. Festivals and the French Revolution. Harvard University Press, 1988.
9. Zammito, John H. A Nice Derangement of Epistemes : Post-Positivism in the Study of Science from Quine to Latour. Chicago: University of Chicago Press, 2004.
10. This view is a form of strict determinism, and current popularizers of continue to enthusiastically endorse it. Perhaps they are “determined” to do so?
11. This view is a form of extreme reductionism, also widely endorsed by current popularizers of science.
12. Zammito, p8
13. Popper, Karl. Logic of Scientific Discovery. 1959
14. For an extended discussion, read Zammito’s chapter “The Perils of Semantic Ascent: Quine and Post-positivism in the Philosophy of Science” in A Nice Derangement of Epistemes. University of Chicago Press, 2004.
15. Hutchinson, p143
16. Hutchinson, p109
17. Giberson, Karl, and Mariano Artigas. Oracles of Science: Celebrity Scientists Versus God and Religion. Oxford: Oxford University Press, 2009.

Evolution: just a theory

One game that my (young) children like to play is a guessing game where both players select a character from among many choices, and by process of elimination, tries to guess the character the other has selected. Questions like “does your character have red hair? glasses?” etc., are used to narrow down the possibilities. Once you have guessed correctly which character your opponent has selected, you can perfectly predict the answer to every question thereafter (and a good many parents likely prolong the questioning to keep the hopes of victory alive for their children). When considered separately, the individual features of each character—glasses, brown hair, purple hat, and so on—mean almost nothing, since they could be features shared with other characters in the game. Only the convergence of multiple features is indicative of a good guess, and the accuracy of that guess is put to the test every time a new question is asked.

A good theory is something like this: an educated guess, based on and consistent with all past work on the topic to date. It allows you to predict how future tests should pan out. In the guessing game, there are limited options to choose from (so the analogy, like all analogies, eventually breaks down). In science, we don’t really know the true way things actually work. What we have are theories—broad explanatory frameworks supported by experimentation, that make sense of our current collection of facts—that we can use to make testable predictions about the natural world. All theories in science are provisional in that they are not complete descriptions of how the world actually works and are subject to future revision; but at the same time they are robust frameworks that can be used to predict how experiments should behave with almost boring regularity. So, far from the colloquial usage of “theory” as speculation, “just a theory” is high praise in science.

The current understanding of evolutionary theory in all its scope and diversity is far more complex than Darwin himself could have ever envisaged. (As a geneticist, I’ve often wished I could have a cup of tea with him to show him how far his theory has grown, especially given his confusion about how heredity worked.) Our understanding of how evolution works has grown by leaps and bounds since the 1850s. What is remarkable is just how much Darwin got “right” given his time and place. His main hypotheses—that species descend from ancestral forms through descent with modification, that and natural selection acting on heritable variation is a significant force in that process—remains the core of modern evolutionary theory. We’ve added a lot of detail since then (population genetics, kin selection, neutral evolution/genetic drift, symbiosis, horizontal gene transfer, molecular exaptation, and so on), but Darwin’s core ideas have produced a wealth of successful predictions. They were a very good “guess” that continues to pay rich scientific dividends.

Whale evolution: an example of converging lines of evidence

One of the things I personally find quite enjoyable about evolutionary theory is the counter-intuitiveness of some of the predictions it makes. One example that is a personal favorite, and one I often use to illustrate how evolution makes sense of converging lines of evidence, is cetacean (whale) evolution. Let’s set up the “problem” that evolutionary biology forces upon us:

• Modern cetaceans are mammals – they nourish their young in utero through a placenta, give birth to live young, and feed newborns with milk – all features of standard mammalian biology.
• Mammals are tetrapods – organisms with four limbs. Mammalian life shows up in the fossil record as an innovation within tetrapods, so mammals are “nested within the set” of tetrapod forms. Not all tetrapods are mammals (amphibians, for example) but all mammals are tetrapods.
• Tetrapods are by and large terrestrial creatures. Having four limbs for locomotion is a distinctly land-based adaptation.

The “problem”, of course, is that modern whales are emphatically not terrestrial, nor do they have four limbs – they have two front flippers and a tail, with no hind limbs in sight. Yet they are mammals, which forces evolution’s hand as it were. Evolution thus is dragged, under protest, to the prediction that modern whales, as mammals, are descended, with modification, from ancestral terrestrial, tetrapod ancestors. Instantly this prediction raises a host of uncomfortable questions: where did their hind limbs go? How did they acquire a blowhole on the top of their heads when other mammals have two nostrils on the front of their faces? How did they transition to giving birth in the water? What happened to the teeth of the baleen whales? What happened to the hair characteristic of mammals? and so on. In some ways, evolutionary thinking about whales creates more difficulties than it appears to solve.

And yet, these difficulties are the stuff of science. If indeed our “educated guess” of terrestrial, tetrapod ancestry for whales is correct, the evidence will show that these transitions, challenging though they may seem, did indeed occur on the road to becoming “truly cetacean”.

Going out on a limb

Anyone who has seen a modern whale skeleton in a museum and noted it carefully may have noticed that though whales lack hind limbs, they do have a bit of bone back there where the hind limbs ought to be. While this is suggestive of a vestigial characteristic (a feature in a modern organism that has a reduced role relative to the role the structure played in an ancestral species), it’s hardly a smoking gun for evolution. Still, it’s consistent with the idea.

When we look at the cetacean fossil record, we also see forms suggestive of a progressive loss of hind limb function and structure over time, as David Kerk and Darrel Falk have elegantly explained before. Again, if one were resistant to evolutionary explanations, it would be possible (if a bit strained) to interpret these creatures as having been created directly as we find them in the fossil record. The facts that we do not see these forms in the present day, and that they seem to blur the distinctions between terrestrial tetrapods and whales might make one a bit uncomfortable, however.

Recent work on cetacean embryogenesis (how whales and their relatives develop from fertilized eggs into fully-formed baby whales) has shed even more light on the issue for modern species, however. Dolphin embryos actually have four limbs early in their development, as well as a few facial hairs, just as any good mammal should have. The hind limbs and hairs are lost later in development, and work on the molecular signaling events that halt hind limb growth and cause the limb bud to regress into the body wall have now been worked out in some detail. Moreover, early in dolphin development the nostrils are distinct and on the front of the face, and only fuse into a blowhole and migrate to the top of the head later in development. Early dolphin embryogenesis is distinctly mammalian and uncannily tetrapod-like.

… and passing the test

Taken in isolation, these facts about whales are interesting trivia. Taken together, however, they begin to form a picture entirely consistent with the prediction that modern whales are derived from terrestrial ancestors. The true strength of evolution as a scientific theory for the origin of whales is this: not that we can prove it, (for no theory is ever proven in science due to its permanently provisional nature), nor that we have full access to every bit of data we would like (consider how fragmentary the fossil record is, for example), but rather that we haven’t been able to disprove it yet, despite our best efforts. Descent with modification remains a productive educated guess that grows stronger with each investigation.

In the next post in this series, we’ll explore some additional lines of evidence for cetacean evolution that further illustrate the predictive power of evolutionary theory.

For further reading

Evidences for Evolution, Part 2a: The Whale's Tale

Evidences for Evolution, Part 2b: The Whale's Tale
J. G. M. Thewissen, M. J. Cohn, L. S. Stevens, S. Bajpai, J. Heyning, and W. E. Horton, Jr. (2006). Developmental basis for hind-limb loss in dolphins and origin of the cetacean bodyplan. Proceedings of the National Academy of Sciences 103 (22), 8414–8418. available freely online.

Ultimately, however, Finch remarks that "science can neither prove nor disprove the existence of God." To him, those who proselytize atheism under the banner of "science" do a disservice to science. The goal of scientists is to understand the physical world around us, and most scientists go into their labs to discover something wonderful about the world, rather than to comment on the existence of God.

In our last two BioLogos podcasts, we looked at the question of transitional fossils and the genetic evidence for evolution. In our final installment of this three part series, we move on to the question of speciation and macroevolution. A common challenge to evolutionary theory is that while life does indeed change over time (what is known as microevolution), no one has ever seen one species evolve into another species (macroevolution). For example, no one has seen a dog evolve into something other than a dog. Because speciation has never been observed, and because science is based on observation, evolution cannot be considered scientific.

In fact, examples of speciation have been observed by scientists. We must also remember that we are able to observe just a tiny window of the long history of life on Earth, and the fact that any speciation has been noted at all is impressive indeed.

Transcript

It’s pretty clear to most of us that life can change over time. For those who aren’t convinced, just take a quick trip to your local animal shelter. Each of the dog breeds there, from the Great Dane to the Chihuahua, descended from a single ancestral population. As you probably already know, that ancestral group was a wolf-like species. -How did these drastic changes take place? Well, basically, genetic variation within that original population was acted upon by selective forces. Now, just to be clear, the selection at work here wasn’t natural. It was the result of breeding done over hundreds of years. But the basic principle is the same. Genetic variation plus some sort of selection results in genetic change. This is evolution.

For the most part we are ok with accepting this. Yet many people still have a problem with the Theory of Evolution. Those suspicious of evolutionary Theory generally split evolution into two categories. Instead of arguing that evolution is completely impossible, they will say something like, “I know microevolution is real, but I just can’t accept macroevolution.”

Kent Hovind, an especially outspoken opponent of evolutionary theory, often makes this argument in his presentations:

“Maybe you’re talking about macroevolution. That’s where an animal changes into a different kind of animal. Nobody’s ever seen that. Nobody’s seen a dog produce a non-dog. I mean you may get a big dog or a little dog, I understand, but you’re going to get a dog, okay?” (source)

But what does this mean? What is the difference between micro and macroevolution anyway, and why is one of them ok while the other is condemned?

Well, like many terms used in the evolution debate, the definitions tend to differ depending on who you talk to. This can make rational discussion difficult. Most opponents of evolution, like Kent Hovind, say that macroevolution refers to one “type” or “kind” of organism evolving into another “kind”. Microevolution, they might say, is evolution within a “kind”. Evolution of one dog breed into another, they would say, is microevolution. Evolution of a “dog into a non-dog”, as Hovind puts it, would be “macroevolution.”’

One big problem with this argument is that “kind” is not clearly defined. It is a subjective term referring to organisms that seem similar to each other. Now, this is a definition that can easily be manipulated. And it doesn’t work very well when asking scientific questions. Because there is disagreement about what they actually mean, the terms micro and macroevolution aren’t often used in scientific literature. But when biologists do refer to “macroevolution”, most define it as “evolution above the species level”.

(Sources: http://ib.berkeley.edu/courses/ib200a/lect/ib200a_lect26_Lindberg_macroevolution.pdf, http://www.nescent.org/media/NABT/, http://evolution.berkeley.edu/evosite/evo101/VIADefinition.shtml, http://www.nhm.ac.uk/hosted_sites/paleonet/paleo21/mevolution.html)

In other words, at the smallest scale, macroevolution is the development of a new species. This definition is more useful because you can objectively determine whether two organisms are members the same species, but “kind” has no specific definition.

So what does “species” mean anyway? How is it different from “kind?” Well, the term species can be hard to define. Life is complex, and categorizing it into clear groups can be tricky. The currently accepted definition of species comes from what we call the “biological species concept.” Basically, the biological species concept says that a species is made of populations that actually or potentially interbreed in nature.

So, two populations that cannot mate to produce successful offspring are by definition separate species. Now, this definition doesn’t always work. For example, when you have a species that reproduces asexually, finding the boundaries between species can be a little tricky. But in most cases it does a pretty good job. It’s a good way to objectively determine where one species stops and another one begins.

The Biological Species Concept is especially useful when you have two species that look and act very similar. Eastern and Western Meadowlarks are a good example of this. They look almost exactly the same. But they cannot interbreed successfully. Therefore, they are separate species. This definition also helps when we study evolution. Where can we draw the line between microevolution and macroevolution? Well, it’s never easy, but having a working definition of this thing called a species helps out a lot. When enough genetic changes accumulate in a population, eventually it loses the ability to mate with others of its species. Then, by definition, it becomes a new species. In other words, macroevolution has occurred.

As we just discussed, many critics claim that macroevolution can never happen—one species can never cross over to become another one. This statement might sound valid, but a little bit of investigation shows that it is not well supported by evidence. For one thing, the only difference between micro and macroevolution is scope. When enough micro changes accumulate, a population will eventually lose its ability to interbreed with other members of its species. At this point, we say that macroevolution has occurred.

The same processes—random mutation and natural selection—cause both micro and macro evolution. There are no invisible boundaries that prevent organisms from evolving into new species. It just takes time. Usually, the amount time required for macroevolution to occur is significant—on the order of thousands or millions of years. That’s why you don’t normally see brand new forms of life appear every time you step out your front door. And that’s also why some people think that speciation never happens at all.

But sometimes macroevolution doesn’t take that much time. In fact, the evolution of new species sometimes happens so quickly that we can actually see it take place! Let’s look at a few recent examples.

Biologists Peter and Rosemary Grant had been studying finches since 1973. They lived on an island called Daphne Major in the Galapagos. It was here that they conducted their studies. When they first began their studies, only two species of Finch lived on Daphne Major: the medium ground finch and the cactus finch. But, in 1981, Peter and Rosemary noticed that an odd new finch had immigrated to the island. It was a hybrid, a mix between a cactus finch and a medium ground finch. It didn’t quite fit in with the other birds. The odd misfit had an extra large beak, an unusual hybrid genome, and a new kind of song. But somehow he was still able to find a mate. The female was also a bit of a misfit and had some hybrid chromosomes of her own. So their offspring were very different from the other birds on the island.

Rosemary and Peter continued to carefully watch the odd hybrid line. They wondered if the birds would become isolated from the other finch species on the island or if they would eventually re-assimilate. After four finch generations, a drought killed off many of the birds on Daphne Major. In fact, almost the entire hybrid line was exterminated. Only a brother and sister pair remained. The two family members mated with each other, producing offspring that were even more unique than their parent line. From that point on, as far as biologists Peter and Rosemary could tell, the odd population of finches mated only with each other. They were never seen to breed with the cactus finches or the medium ground finches on the island. The finches with the strange song had become a brand new species.

(Source: http://www.pnas.org/content/106/48/20141.full)

Another example of speciation, or macroevolution, also took place on an island—this time, on the beautiful Portuguese island of Madeira. According to history books, the Island of Madeira was colonized by the Portuguese about 600 years ago. The colonizers brought with them a few unassuming European House Mice, which they accidentally left on the island. It’s also possible that a group of Portuguese House Mice was dropped off later on.

Recently, Britton-Davidian, an evolutionary biologist at University Montpellier 2 in France, decided to collect samples of the Madeira mice and see how those original populations had changed over time. What she found was surprising. Rather than just one or two species of mouse, she found several. In only a few hundred years, the original populations of Mice had separated into six genetically unique species. The first mouse populations had 40 chromosomes altogether. But the new ones were quite different. Each new variety had its own unique combination of chromosomes, which ranged in number from 22 to 30.

What seems to have happened is that, over time, the mice spread out across the island and split into separate groups. Madeira is a rugged volcanic island with crags and cliffs. So it makes sense that this would have been easy to do. There were many isolated corners for the mice to occupy. Over time, random mutations occurred—some chromosomes became fused together.

Now, In order to reproduce successfully, both parents must have the same number of chromosomes. So when a population develops a chromosome fusion, suddenly that group cannot mate with the other members of its species. It becomes a brand new species. That’s exactly what happened on Madeira. And because of this phenomenon, 6 new species evolved from just 1 or 2 in an extremely short amount of time.

(Sources: http://onlinelibrary.wiley.com/doi/10.1111/j.1365-294X.2009.04345.x/full, http://www.genomenewsnetwork.org/articles/04_00/island_mice.shtml, http://www.nature.com/hdy/journal/v99/n4/full/6801021a.html)

Another fascinating example of macroevolution was recently observed by researchers at Pennsylvania State University. This time, two species combined to make a single new one. In 1997, researchers at Penn State noticed a fruit maggot infestation on some recently introduced Asian Honeysuckle bushes. They decided to investigate the Honeysuckle fly population and determine how it was related to the other flies nearby. When they examined the honeysuckle fly’s genes, the researchers discovered something interesting. The fly appeared to be a hybrid of two native species—the blueberry fly and the snowberry fly.

But the honeysuckle fly’s genetic material was not an exact balance between that of the two parent species. The ratios of DNA varied from fly to fly. This showed the researchers that the honeysuckle flies had been breeding amongst themselves for many generations—probably at least 100. Also, they found that the Honeysuckle Flies were very unlikely to breed with any other species. They bred only on their host Honeysuckle plants. So they weren’t likely to mix with flies that lived on a different host.

According to Dr. Dietmar Schwarz, post-doctoral researcher in entomology, as far as the researchers can tell, “The new species is already reproductively isolated. They seem to be in a niche on the brushy honeysuckle where the parent species cannot compete."

(Source: http://www.psiee.psu.edu/news/2005_news/july_2005/hybrid_insects.asp)

While this kind of speciation—two species hybridizing to create a new one—seems odd, it is a significant mechanism of macroevolution. And it’s especially common in plants. In fact, a new species of weed recently arose this way in Great Britain. In 1991, Richard Abbot, a plant evolutionary biologist from St. Andrews University, noticed an unusual weed growing next to a car park in York. He discovered that the species, an unassuming scruffy weed, was a natural hybrid between the common groundsel and the Oxford ragwort, a plant that was introduced to Britain only 300 years ago. The York Groundsel lives in a different niche, or microenvironment, than either of its parent species. It is able to breed and reproduce, but only with other York Groundsel plants. It cannot successfully reproduce with any other species, including either of its parent plants. Thus, by definition, the York Groundsel is its own new species.

(Sources: http://www.nerc.ac.uk/publications/planetearth/2003/summer/sum03-evolution.pdf, http://www.nature.com/hdy/journal/v69/n5/abs/hdy1992147a.html)

So, as we have seen, macroevolution is an established process. Usually it takes thousands of years to occur, but sometimes we get lucky and catch it in the act. When Kent Hovind said that, “no one has ever seen a dog produce a non-dog” he was technically quite correct. But this statement infers that macroevolution means a drastic and obvious change from one type of organism into another. Those who think this way believe that macroevolution is something like two dogs breeding to suddenly produce a cat, or two guinea pigs mating to produce a mouse.

But this is not how evolution works at all. Over millions of years, a dog-like animal may indeed evolve into a something that looks completely unlike a dog. However, this is not something that we would expect to be able to observe. It just takes too much time. To put the scale of evolution into perspective, consider this. If the average lifespan of a United Stated citizen, 78 years, were a single minute, then single-celled life has been around for nearly 100 years. On this scale, all we get to see is one minute. And even in that time frame we sometimes see new species forming. God’s time is not our time and we tend to forget this. What we do expect to observe is a very slow step-by-step accumulation of tiny genetic changes that eventually result in speciation. And indeed, as we discussed today, this is exactly the sort of evidence revealed in nature.

So, macroevolution is not a “myth” by any means. It is supported by a vast amount of evidence. That evidence includes the fossil record and genetics, as discussed in previous BioLogos podcasts, and, when we get lucky, direct observation of speciation. God, being who God is, could conceivably have created species out of thin air in a single instant. But what if instead if God created and sustained the process by which new species are created? Does that make him less powerful or less "god-like"? Is it somehow more God’s process if it happened in an instant, than it is if it happened over a long period of time? Presumably even if it happened in an instant, it would still happen by some sort of process—only faster.

God’s time is not our time, and perhaps it’s a good idea for all of us to simply stand back in amazement while God does God’s work in God’s time through God’s process.

Monopolizing Knowledge

Science and Scientism

One of the most visible conflicts in current culture is between “scientism” and religion. Because religious knowledge differs from scientific knowledge, scientism claims (or at least assumes) that it must therefore be inferior. However, there are many other important beliefs, secular as well as religious, which are justified and rational, but not scientific, and therefore marginalized by scientism. And if that is so, then scientism is a ghastly intellectual mistake.

But how could it have come about that this mistake is so widespread, if it is a mistake? The underlying reason is that scientism is confused with science. It is natural for readers without inside knowledge of science to assume that science and scientism are one and the same when many leading scientists and science popularizers often speak and act as if they and thus directly promote this confusion. What is more, several major strands within religion also promote this confusion. On the conservative theological wing, science is often rejected because it is confused with scientism, and on the theologically liberal wing scientism is often adopted for the same reason. Whether rejecting or assimilating, religious believers often confuse science and scientism.

Scientism is, first of all, a philosophy of knowledge. It is an opinion about the way that knowledge can be obtained and justified. However, scientism rapidly becomes much more. It becomes an all-encompassing world-view; a perspective from which all of the questions of life are examined: a grounding presupposition or set of presuppositions which provides the framework by which the world is to be understood. In other words, it is essentially a religious position.

The Origins of Scientism

The word science is used with two completely different meanings; confusing the two has a natural tendency to lead to scientism. The historical meaning comes from the word's Latin root, scientia, which means simply knowledge, and indeed the word science was once used to describe any systematic orderly study of a field of knowledge. In today’s common usage, however, "science" refers to the study of the natural world. The "Encyclopédie" (1751-) of Diderot and D'Alembert¹, a classic embodiment of Enlightenment thought, defines the word science to mean knowledge in general, but then focuses on natural science and technology. This is scientism in its youth. Enlightenment writings helped to insinuate scientism as an unacknowledged presupposition into much of the intellectual climate of the succeeding two centuries. From Samuel Johnson's Dictionary (1755), through historians such as Thomas Babington Macaulay (1848), and in vestiges even into the mid twentieth century, "science" was held to refer generally to formal, intellectual learning, yet when specific examples of science are cited these are almost all natural science.

Edward Cheney used his preface to the 1898 edition of Macaulay's history² to criticize him as failing to "treat history as a science". Cheney's attitude is rife with scientism - trying to distinguish between `true' scientific historical knowledge on the one hand, and on the other, literature that fails to qualify as science and hence as true knowledge. As president of the American Historical Society, twenty seven years later, Cheney would champion an explicitly scientistic view of the historian's task as to discover law in history, “... natural laws, which we must accept whether we want to or not, ... laws to be accepted and reckoned with as much as the laws of gravitation, or of chemical affinity” ³ The view is not convincing. The supposed distinction between scientific and unscientific history bears no discernible relationship to the methods of the natural sciences. It is mostly a substitution of “scientific” for "correct" for rhetorical effect.

The continued robustness of scientism is surely partly attributable to this terminological confusion. If science means simply knowledge, then scientism is merely tautologically true. End of story. But if science means a particular type of knowledge, as it does today, then it is essential to recognize that meaning and stick to it. In short what we mean by science today is the inheritance of the Scientific Revolution. In later parts of this series, I shall identify two key defining characteristics of science that encapsulate the two emphases crucial to its development: experimental or natural evidence, and mechanical or mathematical explanation. Before I move on to this task, though, let me pause to address some objections to the whole of my explanatory enterprise.

A Few Possible Objections

One objection that might be raised at this stage is to ask why one should restrict the designation science to the inheritors of the Scientific Revolution. After all, the argument goes, surely we should use whatever strategy is available to discover knowledge. My first answer is immediately to point out that this objection is an example of scientism. It confuses knowledge with science and implies that they are one and the same. I am not at all interested in limiting the ways of obtaining knowledge to those avenues that we call “scientific”. I simply want to be clear that, as a matter of historical fact, science as we commonly conceive it had, and has, a distinctive characteristic approach to methods of discovering and knowing. But why insist on this terminology? Here, my second answer is that science has a well-earned prestige and authority precisely because of its success. This prestige is, of course, one driving force behind the desire of many disciplines to be considered sciences. To use the metaphor of the market today, it is a question of "branding".

A second kind of objection is this: suppose we grant that we will use the word science to mean natural science. Doesn't that just mean the study of nature? So shouldn’t"the study of nature" be our working definition of science then? And if it is, why should one limit the scope of science by an identification of its methods? Surely one should use whatever methods are available to study nature.

My answer is this: the main problem with "the study of nature" as a definition of science is that it simply begs the question: what is nature? We tend to think that "nature" is self-evident; but it isn't. Prior to the Scientific Revolution, nature was populated with gods and teleological imperatives, with intention and purpose. Even in 1686, Robert Boyle (of Boyles' Law) identified eight different senses of the word nature⁴. Boyle's purpose was to deplore the use of, the semi-deity that underwrote Aristotle's physics, which the Scientific Revolution was in the process of superceding, and to replace it with the established order or settled course of things. Moreover, even after the Enlightenment, the romantics such as the poets William Wordsworth and Samuel Taylor Coleridge said that what they were about was the study of nature. Yet no one today would for a moment think to call the poetic understanding of the natural world science. It simply is not adequate to assume that what is meant by nature is obvious.

Instead, I believe, we must use a functional definition of science. Once we have a clear view of what science is, we will have a definition of what we here mean by nature. Nature is what we are studying in natural science. The result of this definition, as we'll see, is entirely consistent with what Boyle was arguing for: the established order or settled course of things.

We will continue this exploration of what we mean by “nature” in the next installment.

Notes

1. Denis Diderot and Jean le Rond d'Alembert, editors. Encyclopédie, ou dictionnaire raisonné des sciences, des arts et des métiers. André Le Breton, Michel-Antoine David, Laurent Durand, and Antoine-Claude Briasson, Paris, 1751-77.
2. Thomas Babbington (Lord) Macaulay. The History of England from the accession of James the second. G. P. Putnam, New York, 1898.
3. Edward P. Cheyney. Presidential address delivered before the american historical association. American Historical Review, 29 (2): 231-48, 1924.
4. Thomas Birch, editor. Robert Boyle,, The Works. Georg Olms Verlangsuchhandlung, Hildsheim, 1966. Volume 5, p167-9.

The beauty of the scientific process is its inherent scepticism. (See "What Scientists Do" by Steven Benner). If there is only one way of reaching a conclusion, the scientific process requires the scientist to remain highly sceptical. The only conclusions in science which are widely accepted are those which are supported by multiple, reinforcing lines of evidence – “all roads must lead to Rome”. If there is even one scientific trajectory that seems to clearly lead off to Peoria instead of Rome (to use a recent analogy of Francisco Ayala), the scientific process demands that the scientist find out why. The scientist who does not retain an attitude of scepticism when there is only a single line of evidence, and particularly one who ignores other, conflicting lines of evidence, is on a stubborn trajectory of his own—a trajectory to failure. If the only reason for following the directions which “lead away from Rome” is a particular view of Scripture, then it is important to consider the possibility of human error. Biblical hermeneutics, after all, is a human enterprise just as science itself is. For example, John MacArthur in his current series on Genesis is human and is interpreting Genesis in his way just like the rest of us. He, wonderful pastor and shepherd that he is, interprets Scripture too. There is good reason to be quite certain that the interpretation he subscribes to is mistaken.

As Christians, we are called to follow Jesus. In so doing, Jesus said we are to love the Lord our God with all our heart, soul and mind—not just our heart and soul. Indeed if we close our mind, we are actually disobeying what Jesus said was the greatest commandment of all. So let’s not be shy about using those minds. Are there multiple independent ways of keeping track of time since the creation of the earth? If so, do each of those ways point to the same conclusion?

The best known method of calculating the age of material on earth depends on the well-established fact that certain elements in the earth’s crust are unstable and decay at a fixed rate that can be measured. (For an introduction to this topic see this BioLogos FAQ.) This instability functions sort of like a set of clocks that have been ticking through the eons of time. Indeed there are many types of unstable elements; there are many ticking clocks. Each of the various clocks tick at a different rate. The rate of each can be calibrated, and, with an amazing degree of consistency, all “clocks” point back to the same starting point: an ancient earth with rocks that are hundreds of millions and even billions of years old. This “ticking clock” technique is known as radiometric dating.^1,2

There are other totally independent ways of estimating the age of material on earth. To appreciate how these work, perhaps we should start with shorter spans of time, which for human beings are much more readily comprehensible. Some of the fondest boyhood memories of one of us (DK) come from visits to the majestic California redwood forests. He especially remembers an exhibit of a section from a giant tree which showed the pattern of growth rings within it. It turns out that these rings accumulate in response to seasonal differences in rainfall and temperature, which in turn produces differences in growth rate. Fastened within this huge slab of wood was a series of tags, proceeding from the surface inward, demonstrating the dates of major historical events: the landing of the Pilgrims on Plymouth Rock; Columbus’ discovery of the New World; the Norman conquest of England, and so forth. It was possible to see in the yearly growth rings a history of what seemed then to be the very distant past!³

Growth layering processes are not restricted to trees. Many species of marine invertebrates accumulate calcium carbonate from their watery environment and incorporate it into some form of shell. Examples would be clams and corals. In fact, for these species, the variation in shell deposition occurs on a both a daily and a yearly basis, so an even finer counting of time periods is possible.⁴

Just as it is possible to count the rings in trees and correlate their age to known historical events in the past, it is also possible to count the banding patterns preserved in the fossils of marine organisms, and use this as a method to estimate their ages. Let’s see how it works.

Astronomical data, developed and analyzed over the past couple of centuries, has revealed that the rotation of the earth is gradually slowing down. This is due to the friction created daily by the moving tides on the earth’s surface, produced by the gravitational pull of the moon and sun. Furthermore, as the earth slows down slightly, some rotational energy is transferred to the moon, which alters its orbit slightly (its orbit is moving slowly away from the earth). The data leading to these conclusions range from analysis of ancient solar eclipses (whose dating allows the precise position of the earth, sun and moon to be determined) to bouncing laser beams off mirrors placed on the surface of the moon by the Apollo astronauts. For our purposes, what will be important is the slowing of the earth’s rotation. This predicts that the length of each day has been slowly increasing since the formation of the earth/moon system. The average increase in the day length is estimated at 2.3 milliseconds (.0023 seconds) per century.^5,6 Hence as we examine events in the past, day length was shorter, by an amount that can be calculated. Ten thousand years ago, a day would have been .23 seconds shorter than it is today. If direct experimental estimates of day length can be obtained, they allow an estimate of the age of the material.

One way that such experimental estimates of day length can be obtained is through the periodic growth rings deposited in the shells of marine invertebrate organisms. Take for example a clam living in an intertidal environment. If the tide is in and the shell is open, it can readily absorb oxygen from water, use aerobic metabolism, and incorporate calcium carbonate into its shells. When the tide is out and the shells are closed, however, little oxygen can be absorbed, anaerobic metabolism is used, shell decalcification occurs, and organic rich material accumulates in the shell. This alternating pattern of shell deposition occurs on a daily basis, and is clearly visible in both shells from living and fossil clam species by microscopic examination. Furthermore, shells contain an identifiable mark resulting from the first freezing day of winter, and from the first really hot day of summer. Hence a yearly growth interval can be readily determined.⁷

When such data are analyzed for a number of fossil species, it is clear that the number of days these organisms experienced each year was higher than today. Given that, we have another clock - a totally independent way of measuring the age of certain fossils. So how well do clocks based upon radiometric dating agree with those based on measuring rings in certain sea shells?

As already mentioned, organisms living 10,000 years ago would have experienced shorter days, but they would only have been shorter by 0.2 seconds. Organisms living 1 million years ago would have experienced a day length that was 20 seconds shorter. If the earth really is very, very old, organisms living 465 million years ago, for example, would have experienced approximately 416 days per year, each day being about 21 hours long.⁷ Amazingly, shelled fossils in formations dated by radiometric clocks to be about 465 million years old show, by their banding patterns, that the days really were three hours shorter. In fact the two sets of clocks agree within 1 percent!

Another way such estimates of ancient day length can be derived is to look at the periodic patterns formed in fine silts in ancient river estuaries. The daily tides produce shifts in the mud, leaving a fine layering pattern, which is recorded in rock as these sediments transform into materials such as sandstone (such deposits are called “rhythmites”). Other shifts in the mud are produced over longer time intervals, including seasonal and yearly shifts. By counting the number of daily depositional layers per year, in a similar fashion to work with marine organism shells cited above, an estimate of ancient day length can be derived. One advantage of the rhythmite analysis method is that it can be applied to more ancient materials, in eras of the earth’s history when organisms suitable for shell analysis were scarce or non-existent. For example, radiometric analysis of certain rock formations in South Australia dated them at 620 million years of age. On this basis one would predict that the day/night cycles should have been about 20 hours long in these formations. Actual measurements of day length from the preserved mud banding patterns, although off from the expected by ten percent (estimated day length is 22 hours) is again consistent with the formation being hundreds of millions of years old just as the radiometric dating has predicted.⁸

In conclusion, there is data derived from three independent sources: the decay of radioisotopes, the growth patterns recorded in fossilized shells of marine organisms, and rocks containing tidal depositional material from river estuaries, which all agree on an ancient age for the earth. Furthermore, by a totally independent method it is also possible to measure the age of the universe as a whole and again it is billions, not thousands of years.

All of the roads in God’s book of Nature “lead to Rome” (i.e an ancient earth) - it is only mistaken human interpretation of Scripture that causes some of our precious brothers and sisters in Christ to end up in Peoria.

The next blog in this series can be found here.

Editor's Note: Dr. Kerk offers a further discussion of the age of the earth in the comment section of this post, beginning here. Dr. Kerk has also included the following graph:

References

1: Elementary principles of radiometric dating are discussed by Richard Dawkins. Dawkins, R. 2009. The Greatest Show on Earth: The Evidence for Evolution. Free Press, New York Pgs. 91-98.

2: Wiens, R.C. 2002. Radiometric Dating: A Christian Perspective. This is a more detailed but still highly readable account of radiometric dating, written by a well-qualified physicist who is also a professing Christian. It can be obtained from the web site of the American Scientific Affiliation: http://www.asa3.org/ASA/resources/Wiens.html

3: Tree ring dating (“dendrochronology”) is discussed by Dawkins, pgs. 88-91.

4: Dating using coral skeletal deposition is discussed by Jerry Coyne: Coyne, J.A. 2009. Why Evolution is True. Viking Penguin, New York. Pgs. 24-25.

5: “Tidal Acceleration”, Wikipedia: http://en.wikipedia.org/wiki/Tidal_acceleration

6: Stephenson, F.R. 2003. Historical Eclipses and Earth’s Rotation. Astronomy and Geophysics 44:2.22-2.27.

7: Zhenyu, Z., Yaoqi Z., Guosheng J. 2007. The periodic growth increments of biological shells and the orbital parameters of Earth-Moon system. Environmental Geology 51: 1271–1277.

8: Williams, G.E. 2000. Geological constraints on the Precambrian history of Earth's rotation and the Moon's orbit. Reviews of Geophysics 38(1):37-59.