“This is 2,300 year old wisdom from the Book of Ecclesiastes that seems to very concisely understand the water cycle. That water evaporates from the ocean, gets stored in the atmosphere via clouds, comes down as snow or rain, and when it comes down on the mountain it’s often stored there, as snow is gathered via groundwater, streams, and rivers, and then through the river, returns to the ocean, again. What a beautiful, complex, interdependent, wonderfully mysterious way of providing water, life to the land … But what does this beautiful system teach us, Father, Son and Holy Spirit, about who we are? What is your word, God, about this river, that runs through the center of where we live?”

In this sermon, Pastor Jon Van Sloten of New Hope Church in Calgary, Alberta, describes how he set out to learn where the water from the Bow River, near their home in the Rocky Mountains, actually comes from. He interviewed scientists who study hydrology and have learned a curious truth about how this particular river keeps a steady flow the full year round. This modulating geophysical “safeguard,” which allows the Rocky Mountains to hold water and let it out at a slow trickle rather than a deluge during the annual snowmelt, speaks to Van Sloten of God’s grace at work in the world—grace we can’t see with the naked eye, but is there all the same.

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.

Transitional Fossils

Some time ago, the Discovery Institute’s Casey Luskin commented on the human origins exhibit at the Smithsonian Institution, suggesting that palaeoanthropologists use evolutionary theory to describe the progression of the human lineage even when they don’t have transitional fossils with which to work. He writes:

What's ironic, however, is that if you ask the question How Do We Know Humans Evolved? the answer you’re given is, “Fossils like the ones shown in our Human Fossils Gallery provide evidence that modern humans evolved from earlier humans.” So whether you find fossils or you don’t, that’s evidence for evolution.

Indeed, it has become an article of faith for those espousing both the young earth creation (hereafter YEC) model and many who hold to the intelligent design model that transitional fossils do not exist and therefore evolution has not taken place. Support for this position usually entails attacking the weak areas of the fossil record, where burial processes have left us little with which to work, or the creation of straw men arguments in which transitional fossils are defined in such a way that none could ever be found. Often this centers on the concept of “missing link,” a term that is habitually used in the popular press and young earth creation and intelligent design literature when referring to fossil remains but which has little to no meaning for biologists or palaeontologists. As Ahlberg and Clack (Ahlberg and Clack 2006) write:

But the concept has become freighted with unfounded notions of evolutionary ‘progress’ and with a mistaken emphasis on the single intermediate fossil as the key to understanding evolutionary transitions. Much of the importance of transitional fossils actually lies in how they resemble and differ from their nearest neighbours in the phylogenetic tree, and in the picture of change that emerges from this pattern.

Contrary to common misconceptions, the fossil record does not record one single lineage for any family of organisms but rather a series of branches, with many related species coexisting synchronously. Darwin hypothesized that the evolutionary record reflected this bushiness and drew such a diagram in his journal. At the time, though, he had little in the way of fossil evidence to back up this position. Much has changed since his day.

An analogy for understanding this “bushiness” was best described by Prothero and Buell (Prothero and Buell 2007). They suggest that the reader consider his or her own genealogy. You and your siblings are the direct descendents of your parents and, while you are similar to them, each of you has different characteristics not shared with them as well as characteristics that you do share. Your parents have siblings as well (your aunts and uncles), and your grandparents are their last common ancestors. These siblings have their own children (your cousins), who have different and similar traits relative to their parents. They are broadly recognizable as being related to you (“oh, I see you have Aunt Edna’s nose”) but three or four generations out, they will become less and less so. These are the “nearest neighbours” that Ahlberg and Clack describe. In this analogy, each of these cousins represents a transitional form from what was (your grandparents) to what will be down the road.

For example, no one would confuse a frog with a salamander but if you trace the fossil record of each back in time, eventually you encounter a fossil, Gerobatrachus hottoni which was recently discovered (Anderson et al. 2008) that is best described as a “frogamander,” having the basal characteristics of both frogs and salamanders. Had we seen such an animal at the time, it is likely we would not have found it remarkable because it would have resembled the species around it. One lineage eventually diverged into frogs, salamanders and other amphibians. Most (just like Darwin proposed in his tree diagram with the little hatch marks at the tip of many branches) went extinct.

Taxonomy and the Beginnings of Human Origins

All life is classified based on a system devised by Carolus Linneaus in 1735 in his remarkable work Systema Naturae. This system gives all recognized species an individual place based on a system of hierarchy. The study of classification is known as taxonomy. A taxonomic ranking for humans would be this:

When a fossil is excavated, the first thing that the palaeontologist does is make a taxonomic assessment of where it fits in a sequence of known fossils. Traits that are shared with other like species or genera are referred to as primitive traits. Examples of this in humans are five fingers and the presence of three arm bones. We share this with all mammals. Traits that are new or are not shared with other like species are referred to as derived traits. Examples of this in humans are the skeletal changes in the pelvis and the foot to allow for walking upright. We do not share these with any other primates.

Transitional fossils in the human fossil record are distinguished at both the genus and species level. This group includes the extinct genera Ardipithecus and Australopithecus and the current genus Homo. All species except Homo sapiens are extinct. Much of the recent study of early humans focuses on the transition from Ardipithecus (‘Ardi’) to Australopithecus (‘Lucy’ and similar fossils) and from Australopithecus to Homo, the genus that led eventually to us. While each of the australopithecine species identified in the fossil record has derived characteristics that separate them from their ancestors and from each other, only one led to the genus Homo.

In future posts, I will describe the evidence for human evolution and why this evidence is compelling. It suggests that we have had a long, varied history filled with great leaps of change, crushing defeat, and eventual expansion into all areas of the globe.

Notes

Ahlberg, P. & J. Clack (2006) A firm step from water to land. Nature, 440.

Anderson, J. S., R. R. Reisz, D. Scott, N. B. Frobisch & S. S. Sumida (2008) A stem batrachian from the Early Permian of Texas and the origin of frogs and salamanders. Nature, 453, 515-518.

Prothero, D. & C. Buell. 2007. Evolution: What the fossils say and why it matters. Columbia Univ Pr.

Alice in Wonderland, by Lewis Caroll

Theology once held a seat of high regard among the sciences. During the Middle Ages theology was the Queen of the Sciences, and it sat enthroned at the core of academic studies throughout Europe. Many of the great European universities developed from the cathedral schools where theology was the nucleus around which all other study revolved and found its meaning.

The reason for this position of favor was that theology was discussion about – or the study of – God himself. In God, believers found their purpose and very existence. Therefore, God was not a position to be reasoned to; rather, reason flowed from one’s understanding of who God is and his relationship to humanity.

As Queen, theology’s function was not to discover all the answers herself but rather to encourage the other subjects – her subjects – to pursue truth. Math should discover that 2+2=4; biology should discover the mechanism of creation; psychology should discover the role of parent bonding in childhood development; but it was the role of the Queen to give meaning to the truths of her subjects.

In other words, 2+2=4 neither proves nor disproves the Creator, but theology – a profound belief in the Creator – sees the beauty in the ordered world around us. Theology and math are not the same. They answer different questions. But they are not completely separate answers; together they form a more complete answer to each of their individual questions. To quote Stephen Jay Gould, they are “nonoverlapping magesteria” to be certain, but they are also “interdigitating in wondrously complex ways along their joint border. Many of our deepest questions call upon aspects of both for different parts of a full answer” (Gould, “Nonoverlapping Magisteria,” Natural History 106 (March 1997).

It is unfortunate that Gould’s later explanation of these nonoverlapping magesteria left so little room for theology; in a sense, banishing the Queen almost completely to the hinterlands of the academic kingdom. The image of these nonoverlapping magesteria “interdigitating in wondrously complex ways,” however, is still worth considering. This image serves as a reminder that one should not reason from God or theological perspectives to mathematical principles or scientific theories anymore than one should reason from mathematical principles or scientific theories to the existence of God or the non-existence of God. In their “interdigitating,” however, in the beautiful harmonies between theology and the other sciences a fuller answer is given – an answer that provides not only facts but also meaning.

Unfortunately, the history of theology’s reign through the ages is questionable at best. The Queen far too often hampered instead of encouraged the pursuit of truth by her subjects. Today, many put the Queen at direct odds with her subjects, and this has led to a comical and tragic caricature of theology in our current society – a Queen who settles all difficulties, great or small, with the same solution, without bothering to look around, and by yelling, “Off with their heads.”

As Christians, who care deeply for the pursuit of truth, we cannot – and must not – attempt to restore theology to a place of prestige by destroying the work of her subjects or by belittling the work of those who practice them. We must not attempt to settle every difficulty between theology and the other sciences by calling for the heads of others to roll while we bury our own heads in the sand.

Rather, as theologians, whether professional or lay, we must assist theology to ascend to her throne as Queen of the Sciences by encouraging the pursuit of truth in all fields wherever they lead, by humbly entering into discussion with her subjects concerning the truth they discover, and by proclaiming the Truth that gives meaning to all truth – Jesus Christ, our Lord.

Introduction

One of the reasons that some of us are hesitant to accept evolutionary creation is that it seems to make God responsible for the suffering and death of innumerable creatures over millions of years—before humans ever existed or sinned against their creator. Since we believe in and worship a God who is loving, benevolent, and all-powerful, it sounds quite implausible that our God would have created a world like that; therefore, any scientific evidence for evolution must be incorrect.

Other people look at the scientific evidence for evolution and find a compelling case that it has taken place during our earth's history. On this basis they may conclude that if evolution is true, then the belief in an all-powerful, perfectly good God must be false!

The trouble with both of these views is that they tend to invoke a completely abstract, philosophical god, not the living God of the Bible—the God who became a human being, experienced unimaginable suffering, and died in a grotesque and humiliating public display. The death of Jesus completely defied the expectations (and common sense) of his followers, as well as the expectations of any “rational” understanding of the way the Creator of the universe should act in the world. On the cross, in the person of Jesus, God took upon himself far more suffering than any creature has ever experienced.

If God himself is willing to die, particularly in such a gruesome way, then perhaps we should at least consider the possibility of God allowing the death of other creatures, too. But would this really be compatible with what we know of God through Scripture? In this essay, we will explore this quandary through a “theology of the cross”, a concept articulated by pastor George Murphy in his book Cosmos in the Light of the Cross.¹

Theology of the cross

Before we jump into the theological problems associated with evolution, let’s take a look at how we understand Christian theology itself. For the reformer Martin Luther, any theology (or science) that tries to reach knowledge of God apart from the cross is bad theology.² Instead, Luther pointed to a theologia crucis, in which the true God is seen first and foremost “through suffering and the cross”. To make his point even clearer, Luther insisted that “the CROSS alone is our theology”.³ It is the lens through which we view everything.

Of course Martin Luther, having lived in the 16th century, was not aware of the vast history of life on our planet (or any other aspect of modern science, for that matter), but George Murphy draws from Luther’s teachings the foundation that all human knowledge begins with the Word made flesh and crucified.⁴ With the cross of Christ as the ultimate framework through which we view reality, we are bound to view the processes of nature quite differently. As Murphy explains it,

A theology of the cross is an explication of belief in a God who becomes a participant in the history of the universe and thereby shares in the suffering, loss, and death that are part of worldly experience.⁵

God does not sit idly by and watch unaffected as his creatures suffer, but neither does he swoop in and make everything completely effortless and easy. Instead he chose another way, the crucifixion of Jesus—certainly not the approach that we would have preferred! The apostle Peter went so far as to try to talk Jesus out of it, but he was met with a stern rebuke (Matthew 16:21-23).

Why is evolution so disconcerting to Christians?

The problem of suffering throughout all of human history is troubling enough for us to reconcile with a loving, personal God. But in addition to that, the discovery of vast numbers of fossils reveals that death has taken place on a far greater scale than we had ever imagined. Both the wide variety of extinct creatures and their sheer numbers is quite staggering, and it raises questions about our Creator:

The picture of a God who is immune from suffering and death but who forces organisms through millions of generations and extinction is disturbing to those who believe in a God of love.⁷

The mass extinction of life on earth was already well established by the early 19th century—decades before Darwin’s research—and extinction can be empirically verified independent of any theory of evolution.⁸ The fact that the earth’s crust is a veritable graveyard of long-lost creatures is deeply troubling, and as late as the 1790’s, distinguished intellectuals such as Thomas Jefferson denied the very possibility of extinction.⁹

But in addition to the reality of species extinction, the theory of evolution by natural selection proposes that new species also arise in an environment containing widespread pain and death. Both the creatures that are now living and those that are gone are tainted by an “acrid smell of death”.¹⁰ It makes us wonder, if our Creator is not the God of the dead, but of the living (Mk. 12:27), where is God’s presence in the evolutionary picture?

In all honesty, creation through evolution is not what we would expect from God, but Scripture is full of examples in which God acts in unexpected ways. After all, God’s choosing to undergo an agonizing death on a cross is not what we would expect from the all-powerful Creator of the universe, either. In both cases, new life comes about through pain, suffering, and death. As George Murphy puts it,

A priori ideas about God have to be overcome, and God's character has to be learned from God's self-revelation.¹¹

God’s fullest self-expression is in Jesus Christ himself, one who is intimately familiar with and personally endured creaturely pain and death. The theology of the cross reveals that God's self-revelation takes place in situations of suffering, loss, and apparent hopelessness, much like situations that occur through natural selection.¹²

The crucifixion is disconcerting too

Not only is creation through evolution an unexpected and unsettling process, but so is the crucifixion of Jesus! Killing someone by hanging them on a cross is an unbearably painful, prolonged, humiliating form of death. It was such a horrific type of public execution that it wasn't until after the Roman Empire stopped the practice of crucifixion—and people no longer witnessed it personally—did the cross become a visual object of devotion.¹³ Our culture is sufficiently removed from crucifixion that we are desensitized to its original significance, but to connect it to our current context, imagine the reaction you would get by wearing jewelry designed to look like an electric chair.¹⁴

Once we are more attuned to the brutality of crucifixion, it seems all the more striking that the cross is the sign of God’s work, what George Murphy calls “the trademark of God”.¹⁵ The suffering and death of Jesus is featured prominently in the Gospels, but the crucifixion-resurrection pattern is strongly resonant within the Old Testament, too. Israel suffered and toiled as slaves in Egypt for centuries before they were rescued in the Exodus, bringing life to a people who were spiritually dead. Centuries later, the nation of Israel would experience death again when the Babylonians destroyed the Davidic monarchy, burned their Temple, killed their people, and sent many into exile.¹⁶ Neither Israel (God’s chosen people) nor Jesus (God’s own son) were spared from death and suffering; rather, suffering seems to have been the way in which God re-forms and renews humanity to fully bear His own image.

Redemption extends to all of creation

Fortunately, God’s story does not end with death. God gives new life after his creatures have been subjected to terrible circumstances. Redemption was promised to Israel itself—Ezekiel’s vision of the valley of dry bones describes how God would renew His chosen people (Ezek 37:1-14). Later, the astonishing resurrection of Jesus made salvation possible not only for Jews, but for all people in Christ (Gal 3:26-29). Ultimately, the New Testament makes it clear that God’s renewal will encompass the entire Creation:

For God was pleased to have all his fullness dwell in him, and through him to reconcile to himself all things, whether things on earth or things in heaven, by making peace through his blood, shed on the cross. (Colossians 1:19-20)

With all wisdom and understanding, he made known to us the mystery of his will according to his good pleasure, which he purposed in Christ, to be put into effect when the times reach their fulfillment—to bring unity to all things in heaven and on earth under Christ. (Ephesians 1:8-10)

Christians are accustomed to thinking of the death of Christ in regard to humans, but our culture rarely acknowledges God plan for the redemption of His entire creation. This is partly attributable to the fact that discussions of creation and origins are often separated from the topic of salvation.¹⁷ In doing so we tend to marginalize Jesus as we argue about Genesis. Rather than fall into this trap, if we view nature through a theology of the cross, we will see Christ as both the alpha and the omega point in discussions of life’s history and life’s future. With this perspective, we are more apt to sense our solidarity with the rest of creation as we wait in eager anticipation of a glorious future:

The creation waits in eager expectation for the children of God to be revealed. For the creation was subjected to frustration, not by its own choice, but by the will of the one who subjected it, in hope that the creation itself will be liberated from its bondage to decay and brought into the freedom and glory of the children of God. (Romans 8:19-21)

Conclusion

As part of the Church’s conversation about the problem of natural evil, this essay is meant to be a brief introduction to a “theology of the cross”. One can explore this concept in greater detail in Murphy’s book The Cosmos in the Light of the Cross. While there is a lot more to be said, let me conclude with the following observation: though evolution may not be compatible with some interpretations of Christianity, evolutionary creation is certainly compatible with the crucified Christ and the theology of the cross. In the person of Jesus, God suffers with the world and ultimately redeems it. As George Murphy puts in, “The world's pains are God's stigmata.”¹⁸

Explore this Topic Further

• Miller, Keith. “And God saw that it was good”: Death and Pain in the Created Order. BioLogos series
• Murphy, George L. The Cosmos in the Light of the Cross. Harrisburg, PA: Trinity Press, 2003.
• Murphy, George L. “Cross, Evolution, and Theodicy: Telling It Like It Is”. In The Evolution of Evil. Edited by G. Bennett, M.J. Hewlett, T. Peters, and R.J. Russell. Göttingen: Vandenhoeck & Ruprecht, 2008.
• Southgate, Christopher. The Groaning of Creation: God, Evolution, and the Problem of Evil. Louisville, KY: Westminister John Knox Press, 2008.

Notes

1. Murphy, George L. The Cosmos in the Light of the Cross. Harrisburg, PA: Trinity Press, 2003.
2. Murphy, p34
3. “CRUX Sola Est Nostra Theologia,” in D. Martin Luthers Werke, Kritische Gesammtausgabe (Weimar: Hermann Boehlau, 1892), 5:172. The captitalization is in the original. Cited in Murphy, p26.
4. Murphy, p108
5. Murphy, p4
6. Murphy, p43
7. Murphy, p3
8. Some Christians ascribe animal death to some combination of Adam’s fall and Noah’s flood, but this does not resolve the problem that the animals are still suffering and dying through no fault of their own. See Keith Miller’s BioLogos series Death and Pain in the Created Order for the limitations inherent in a fall-based theodicy.
9. Rudwick, Martin. The meaning of fossils: Episodes in the history of paleontology. Chicago, University of Chicago Press, 1985.
10. See Jeff Schloss’ BioLogos essay Evolution, Creation, and the Sting of Death
11. Murphy, p63
12. Murphy, p122
13. Murphy, p27
14. This example is drawn from an evangelical outreach event held by a Christian student group in Innsbruck, Austria. On campus one day, they started conversations with their classmates by asking the question, “Would you wear an electric chair on your neck?”
15. Murphy, George L. The Trademark of God: A Christian Course in Creation, Evolution, and Salvation. Wilton, Conn.: Morehouse-Barlow, 1986.
16. Murphy, Cosmos in the Light of the Cross, p 31-32.
17. Murphy, p35
18. Murphy, p87

George Murphy notes that while the science and theology dialogue has grown considerably in the past 30 years, much of it remains at an academic level. While it provides an important foundation, that alone is not going to do the job that the church needs it to do—to come out in Christian education in parishes, in preaching, in pastoral care, in the social action of the church.

During his seminary education, Dr. Murphy also gained a deeper understanding of Luther’s theology of the cross, and he realized that it’s really the best way to approach the science and theology dialogue. The theology of the cross helps us deal not only with an issue like evolution, and but more generally with the whole question of how God acts in the world and how we know God.

Most science and theology dialogue is restricted to discussion of creation and origins. But at the core of the Gospel of is not simply the doctrine of creation—it’s salvation, it’s the work of Christ in saving humanity and in saving the whole creation.

First posted April 29, 2012

In Part 2 of this series, we concluded by noting that, as Christian geologists willing to consider the possibility, we find no compelling evidence that the earth’s geological features can be explained by a global Flood. Here we consider three lines of evidence: global salt deposits, the order of deposition of sediment layers in the Grand Canyon, and the sequence of fossils in geological strata.

Salt Deposits

There are many places around the earth with layers of salt, some thousands of feet in thickness. Just off the southern coast of the United States in the Gulf of Mexico, thick salt deposits sit beneath thousands of feet of sediment (Fig. 1). These deposits lie within the layers that are said to have been deposited by the Flood.

We understand how salt beds form. At locations such as the Bonneville Salt Flats of Utah, or at the Dead Sea at the border of Israel and Jordan, salt is actively forming. Salt beds form when water is evaporated. During evaporation, the concentration of dissolved ions increases until the water cannot hold the salt in solution anymore and mineral salt begins to form. If a presently unknown or poorly understood process could produce salt without evaporation, as argued by young-earth advocates¹, it would quickly dissolve as soon as it came into contact with flood water, just as the salt from your saltshaker rapidly dissolves when added to water or moist food.

One might argue that the waters from the Flood could have evaporated to leave behind the salt deposits we see today, but there is a serious problem. The thousands of feet of sediment on top of the salt is also said to be from the Flood, meaning the flood waters cannot have evaporated to produce the salt and still be present and violent enough to transport thousands of feet of sediment to the same location. In other words, a single flood cannot be called upon to explain both the salt and the overlying sediment. For those who wish to argue that natural processes could have been vastly different during the Flood, there are at least two replies. First, under such a scenario, there is no point in Flood Geology studies any more than in normal studies, for nothing could be gained by the study of unknowable processes. A more important question, however, would be to ask why God would alter natural processes just to make Flood sediments look like they are not flood sediments. What would the purpose be? (We will revisit this thought later.)

Grand Canyon: Order of Deposition

The Grand Canyon is made up of a sequence of layers that defies any reasonable attempt to explain by a single flood. The alternating layers of limestone, sandstone and shale each form in unique environments. If these deposits were formed at different times under various sea-level stages, it is quite simple to explain the different grain sizes and rock types as a function of depth and distance from the shore line. If explained with a single catastrophic flood that abided by God’s natural laws of physics and chemistry, logic must be stretched beyond the breaking point.

As a very simple observation, consider instructions given in virtually every gardening book. A good soil will have a mix of sand, silt and clay. To determine the quality of your soil, you take a handful or two, put it in a clear container, add water and shake it up. When you stop shaking, the coarse grained material will settle out first resulting in a sequence of layers: sand on the bottom, then silt, then clay. You can readily see how much of each you have by the thickness of each layer.

This is informative of what we see in flood deposits. As moving flood waters slow down, finer and finer grained sediment settles out resulting in a “fining upward” sequence. If most of the Grand Canyon layers were laid down by the Flood, then we should see the same thing – a “fining upward” sequence. Instead, we see a series of alternating layers of fine and coarse grained material, with smaller-scale alternating layers within the larger ones (Fig. 2). Increasing the violence of a flood does nothing to negate the standard order of deposition. Repeated surging of flood waters across the surface likewise offers little explanatory power; in this case we might expect successive layers, each with their own “fining upward” sequence, but such is not what is observed. Further, the Grand Canyon includes multiple layers of limestone, which are never found in flood deposits of any magnitude. Even in floods as massive as one thought to have catastrophically deluged the once dry Mediterranean Sea basin with thousands of feet of water – limestone beds are conspicuously absent.

Fossil Sequence

If a massive flood were responsible for the fossil record, what would we expect to see? If the Flood was violent enough to rip chunks of rock up from the earth and move entire continents (standard Young Earth claims)², then it should be obvious that life forms from every imaginable niche would be tumbled and mixed together (Fig. 3a). We should find numerous examples of mammoths mixed with triceratops, and pterodactyls mixed with sparrows. Ferns and meadow flowers should be found in the same deposits, along with trilobites and whales. Further, we should find all major life forms still living today, for Genesis 7:8-9 is clear in stating that all terrestrial animals were preserved on the ark.

What we actually observe is far different (Fig. 3b). There is an orderly sequence where trilobites only occur in very old rocks, dinosaurs in later beds, and mammoths in still later layers. Organisms like flowers and ferns are present together in more recent deposits, but only ferns with no flowers are found in older deposits. Some readers will recognize this as an example from the “geologic column” and be tempted to discount it as a fabrication. For those thinking this way, consider what Henry Morris had to say in both editions of Scientific Creationism:

“Creationists do not question the general validity of the geologic column, however, at least as an indicator of the usual order of deposition of the fossils…”⁵

If we revisit the Grand Canyon for a moment, is it not striking that there is not a single dinosaur, mammoth or bird in the entire exposed sequence? Not one. To find these, you have to go to younger sediments found in deposits outside the canyon that have not been fully eroded away yet. How could such a lack of mixing be possible if the Flood was violent enough to move continents?

Is it possible to fully understand and practice Scripture without connecting with science? If science reveals God’s attributes, how can we fully relate to Him without some ongoing reference to the information revealed in scientific inquiry? Even more specifically, as preaching pastors, how many are we excluding if we ignore important facets of our congregations’ worldviews?

Now in a collaborative environment like this, it is easy to stay on an intellectual level. But we are pastors who are practitioners, so let me speak personally to get the discussion into the realm of the church world and what may or may not work for you. Some 27 years ago, while exploring whether or not to go to pastor Northland Church, I sensed I’d found kindred spirits when reading in its philosophy of ministry:

People are not just to be understood as sinners but as beings greatly affected by the bodies and physical world they inhabit.

How then would I best address that physical world in the context of understanding its value to our spiritual formation?

Different Approaches to Scripture and Science

Since the sermon is the main component used to build the congregation’s collective approach to understanding how the church relates to the world, I want to take a few moments to lay out what has worked in my preaching and what has not when it comes to science and more specifically the subject of evolution:

1. I decided on a hermeneutical approach. How would God’s patterns in creation published in scientific findings inform my understanding of Scripture?

• I would not use the “Science and Faith are in conflict” (J.W. Draper/A.D. White¹) approach, since I am neither a fundamentalist nor someone whom would wish to violate the spirit of those who penned Scripture who understood God to be over all the world, both hill and Temple (Psalm 24:1-10).
• I would not use S.J. Gould’s² “Non-Overlapping Magisteria” approach, which “ghettoizes” both science and faith. To say one only answers “how” and the other only answers “why” is to miss the richness of both.
• I would not use Pierre Teilhard de Chardin’s³ or Ian Barbour’s³ “Integration / Unity” approach, since such an approach requires extensive knowledge of both science and theology and almost inevitably leads to process theology.
• I would use the “Dialogue” (W.G. Pollard⁵) approach, since it emphasizes insight and investigation rather than answers, thereby leading to a sense of wonder and worship. Such an approach minimizes the hubris of knowledge (that will almost certainly pass away) and the hostility toward different perspectives.

2. I decided on a related-referential model rather than an issue-oriented one.

• Any model chosen must fit the personal style of the preacher or it will become uncomfortable and soon unused. I am more the Columbo/sloppy trench coat, “Oh that reminds me…one more thing…” investigator rather than a “light bulb hanging over the head breaking down your resistance” kind of confronter. So I use science as “now what do you make of that?” kind of illustration rather than an argument for my perspective.
• The model must also fit the personality of the church. In our church issue-oriented subjects must be taught in classes or small groups where people have the chance to question/comment in ways not usually done in response to sermons.

3. Our church has decided that being a witness of the incarnate Christ means engaging, and learning from, the world as it is presently.

• Following God’s example in Christ is entering into the world and serving in all its realms: spiritual, emotional, physical, and social.
• Christ used the common knowledge people already had (much of it from nature) to reveal God.

Recognizing Cultural Perspectives

Having laid out what seems like a tidy approach, I will now recognize the difficulties I have experienced, as a pastor, pertaining to evolution, for understandable but remediable reasons. The church has a particular culture that prevents fully engaging science.

1. Most in a congregation do not decouple or differentiate the belief in a philosophy of random and purposeless evolution from the instances of incremental improvements that may point ultimately to an Organizing Principal.
2. Most have not been taught the literary genre distinctions between the writings of Genesis 1 and a science textbook.
3. Most have not considered the possibility that Adam and Eve may not have been uniquely and separately physically created for their sole role in the beginning of human kind. They need alternatives involving figures that do not contradict the point of the narrative.
4. Most have not considered the complementary nature of the Biblical narrative of redemption out of death and the evolutionary one.

To be sure, when a pastor addresses the alternatives, or even makes an explanatory reference using evolution, that pastor can expect a variation of this conversation I had with a parishioner (who walked out during a sermon) a little over a year ago:

____________, I know I upset you with the reference I made to evolution. You have been listening to my teaching for many years. I hope you know by now how the high view of Scripture as the final source of truth and authority I hold and this church holds. 'Well, I thought I did but now I am not so sure,' answered this lady who has been trying to get Ken Hamm to our church for some years. You know I would never do anything to lessen the importance of Scripture. 'Pastor, when you confess evolution, you not only make a liar out of Scripture, you become the reason young people are not following God and are living lives without regard to the Bible, and are in some cases committing suicide.'

This woman is not an unintelligent person. She is a professional nurse and is leading in a mission organization. She was just scared. Happily, she is still in the church and has decided after some more reflection that maybe I do not want to lead young people into orgies and death after all.

Summary Thoughts

In 1632 Galileo warned his fellow believers of a trap they were walking into by resisting the conclusions of a scientific investigation:

Take note, theologians, that in your desire to make matters of faith out of propositions relating to the fixity of sun and earth you run the risk of eventually having to condemn as heretics those who would declare the earth to stand still and the sun to change position--eventually, I say, at such a time as it might be physically or logically proved that the earth moves and the sun stands still.⁶

We would do well to be the church learning God’s truth as discovered by scientists, not resisting its discomfort or its perceived threat to our traditional interpretations of Scripture.

We worship a God of history, and references to our physical world fit well, given some time, into our metaphysical journey. One only has to look at the Old and New Testaments to see how central the elements of creation are to understanding the activity, and thus the “nature” of God. The references are not simply meant to be objective facts; they are to open the door to vistas beyond. If postmodernism has made us aware of the illusion of pure objectivity, then it has also taught us something of the value of pre-modernism, where the lines between the physical and spiritual are connecting points.

Of course nature is not prescriptive, nor does it present comprehensive pictures of God’s personality. One of the most intellectually capable scientists I know does not believe in God because of his observations of ants organizing slave colonies. It offends his sense of egalitarianism. Talk about making a mountain out of an anthill! Theologizing from particular scientific observations is hyper-interpretive.

Yet, as all creation was made by and for Him (Colossians 1:16-17), when it comes to the insights that may be offered by scientific information (especially evolution) it is difficult for those who have been given a modicum of faith not to see the possibility of:

• An Organizing Principle
• An Orchestrated Similarity among the physical, personal, social, and spiritual realms
• An increased ability and likelihood to respond to the outside world in ways that benefit all
• Redeeming relationships involving sacrifice, not all of which are initially positive or intentional (Romans 8:28)
• Problematic instances that would seem to negate the idea of a loving kind Creator may be a part of a more positive trend.
• Greater confidence, as a result of faith, in uncontrollable circumstances being used for good eventually

My goal as a pastor is to equip the saints in my sphere of influence to see Christ and to worship Him. If those in my influence only can see God in Scripture, then they are half blind. But if we together can help each other see the unfolding redemptive purposes of every realm - of scientific inquiry, of business practice, of artistic expression, of church/family support for every individual in every field of endeavor – then we will be not only 20-20 but 3-D in every direction!

Of course, such a result will require a more comprehensive approach in preaching. And such comprehension will require a continuing dialogue with those who can help us see the truth from different perspectives.

Notes

1. John William Draper, A History of Conflict Between Religion and Science, 1874; Andrew Dickson White, History of the Warfare of Science with Theology in Christendom, 1894.
2. Stephen Jay Gould, Rock of Ages, 1999.
3. Pierre Teilhard de Chardin, The Phenomenon of Man, 1959.
4. Ian Barbour, Religion and Science, 1997.
5. William G. Pollard, Physicist and Christian: a dialogue between the communities, 1961.
6. Galileo Galilei, Dialogue Concerning the Two Chief World Systems, 1632.

For more, be sure to read our FAQs How are the ages of the Earth and universe calculated? and What scientific evidence do we have about the first humans?, as well as our recent infographic How Do We Know the Earth is Old?.

Author's Note from Joy Walters

As I mentioned in my first post, I grew up skeptical of the whole idea of evolution. One contributor to my disbelief was the lengthy timescale for the “tree of life” that was presented with the theory. I would hear, for example, that dinosaurs lived hundreds of millions of years ago, but there was no explanation of why this was true; it was just given as a fact. No one explained the methods of dating, and so I thought biologists simply estimated the ages of species to fit their preconceived notions of how long it would take for one species to emerge from another. It also seemed like the ages were periodically revised and extended farther back in time, and I figured scientists needed to manipulate numbers to make evolution plausible. This, in my mind, made the theory both unbelievable and dismissible.

Once I learned about the techniques used to date fossils, I realized that my first impressions were wrong; the ancient ages of species are scientific determinations rather than scholarly conjectures. However, I have found in recent conversations that Christians remain skeptical of old ages and the evolutionary time scale. For this reason, I wanted the videocast to address the process of fossil dating (what the methods are and why they are accurate) while focusing on cases where hominid fossils were discovered and dated using these very methods. My hope is that Believers would be informed about the evidence for human evolution and its scientific grounding.

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.

What's the Problem?

Many secular and many evangelical voices agree on one ‘truism’—that if you are an orthodox Christian with a high view of the authority of the Bible, you cannot believe in evolution in any form at all. New Atheist authors such as Richard Dawkins and creationist writers such as Ken Ham seem to have arrived at consensus on this, and so more and more in the general population are treating it as given. If you believe in God, you can’t believe in evolution. If you believe in evolution, you can’t believe in God.

This creates a problem for both doubters and believers. Many believers in western culture see the medical and technological advances achieved through science and are grateful for them. They have a very positive view of science. How then, can they reconcile what science seems to tell them about evolution with their traditional theological beliefs? Seekers and inquirers about Christianity can be even more perplexed. They may be drawn to many things about the Christian faith, but, they say, “I don’t see how I can believe the Bible if that means I have to reject science.”

However, there are many who question the premise that science and faith are irreconcilable. Many believe that a high view of the Bible does not demand belief in just one account of origins. They argue that we do not have to choose between an anti-science religion or an anti-religious science.¹ They think that there are a variety of ways in which God could have brought about the creation of life forms and human life using evolutionary processes, and that the picture of incompatibility between orthodox faith and evolutionary biology is greatly overdrawn.²

For example, there have been a number of efforts to argue that there may be evolutionary reasons for religious belief. That is, it may be that capacity for religious belief is ‘adaptive’ or is connected to other adaptive traits, passed down from our ancestors because they supported survival and reproduction. There is no consensus about this among evolutionary biologists. Nevertheless, its very proposal seems to be completely antithetical to any belief that God is objectively real. However, Christian philosopher Peter van Inwagen asks:

Suppose that God exists and wants supernaturalistic belief to be a human universal, and sees (he would see this if it were true) that certain features would be useful for human beings to have— useful from an evolutionary point of view: conducive to survival and reproduction—would naturally have the consequence that supernaturalistic belief would be in due course a human universal. Why shouldn’t he allow those features to be the cause of the thing he wants?—rather as the human designer of a vehicle might use the waste heat from its engine to keep its passengers warm.³

Van Inwagen’s argument is sound. Even if science could prove that religious belief has a genetic component that we inherit from our ancestors, that finding is not incompatible with belief in the reality of God or even the truth of the Christian faith. There is no logical reason to preclude that God could have used evolution to predispose people to believe in God in general so that people would be able to consider true belief when they hear the gospel preached. This is just one of many places where the supposed incompatibility of orthodox faith with evolution begins to fade away under more sustained reflection.

However, many Christian laypeople remain confused because the voices arguing that Biblical orthodoxy and evolution are mutually exclusive are louder and more prominent than any others. What will it take to help Christian laypeople see greater coherence between what science tells us about creation and what the Bible teaches us about it?

Pastors and People

In my estimation what current science tells us about evolution presents four main difficulties for orthodox Protestants. The first is in the area of Biblical authority. To account for evolution we must see at least Genesis 1 as non-literal. The questions come along these lines: what does that mean for the idea that the Bible has final authority? If we refuse to take one part of the Bible literally, why take any parts of it literally? Aren’t we really allowing science to sit in judgment on our understanding of the Bible rather than vica versa?

The second difficulty is the confusion of biology and philosophy. Many of the strongest proponents for evolution as a biological process (such as Dawkins) also see it as a ‘Grand Theory of Everything.’ They look to natural selection to explain not only all human behavior but even to give the only answers to the great philosophical questions, such as why we exist, what life is about, and why human nature is what it is. Doesn’t belief in the one idea—that life is the product of evolution—entail the adoption of this whole ‘world -view’?

The third difficulty is the historicity of Adam and Eve. One way to reconcile what current science says about evolution is to propose that the account of Adam and Eve is symbolic, not literal, but what does this do to the New Testament teaching of Romans 5 and 1 Corinthians 15 that our sinfulness comes from our relationship with Adam? If we don’t believe in an historical fall, how did we become what the Bible says we are—sinful and condemned?

The fourth difficulty is the problem of violence and evil. One of the greatest barriers to belief in God is the problem of suffering and evil in the world. Why, people ask, did God create a world in which violence, pain, and death are endemic? The answer of traditional theology is—he didn’t. He created a good world but also gave human beings free will, and through their disobedience and ‘Fall’, death and suffering came into the world. The process of evolution, however, understands violence, predation, and death to be the very engine of how life develops. If God brings about life through evolution, how do we reconcile that with the idea of a good God? The problem of evil seems to be worse for the believer in theistic evolution.

I have been a pastor for almost 35 years, and during that time I’ve spoken to many laypeople who struggle with the relationship of modern science to orthodox belief. In the minds of most laypeople, it is the first three difficulties that loom largest. The fourth difficulty—the problem of suffering and death—has not been posed to me as often by parishioners. Yet in some ways the problem of suffering goes along with the third question regarding the historicity of the Fall. Without the traditional view of the historicity of the Fall, the question of evil would seem to become more acute.

Therefore, below I will lay out three basic problems that Christian laypeople have with the scientific account of biological evolution. Nothing here should be seen as meeting the need for rigorous, scholarly arguments in answer to these questions. These are popular-level pastoral answers and guidance. As a pastor I have had to draw heavily on the work of experts. The first question, about Biblical authority, requires that I draw on the best work of exegetes and Biblical scholars. To answer the second question, about evolution as a ‘Grand Theory of Everything,’ I need to draw on the work of philosophers. When we come to the third question regarding Adam and Eve, I must look to theologians.

In short, if I as a pastor want to help both believers and inquirers to relate science and faith coherently, I must read the works of scientists, exegetes, philosophers, and theologians and then interpret them for my people. Someone might counter that this is too great a burden to put on pastors, that instead they should simply refer their laypeople to the works of scholars. But if pastors are not ‘up to the job’ of distilling and understanding the writings of scholars in various disciplines, how will our laypeople do it? This is one of the things that parishioners want from their pastors. We are to be a bridge between the world of scholarship and the world of the street and the pew. I’m aware of what a burden this is. I don’t know that there has ever been a culture in which the job of the pastor has been more challenging. Nevertheless, I believe this is our calling.

Next week, Keller begins to unpack the individual questions, beginning with how we can understand evolution in relation to a literal reading of the Bible.

Notes

1. A good popular level book by a scientist is Denis Alexander, aptly titled: Creation or Evolution-do we have to choose? (Oxford: Monarch Books, 2008.)
2. See Christian Smith, ed. The Secular Revolution: Power, Interests, and Conflict in the Secularization of American Public Life (University of California Press, 2003.) and Rodney Stark For the Glory of God : how monotheism led to reformations, science, witch-hunts, and the end of slavery (Princeton: 2003.)
3. Peter van Inwagen, “Explaining Belief in the Supernatural”, in J.Schloss and M.Murray, ed. The Believing Primate: Scientific, Philosophical, and Theological Reflections on the Origin of Religion. (Oxford, 2009) p.136.

Today's video features Michael Ramsden of the Oxford Centre for Christian Apologetics and is courtesy of filmmaker Ryan Pettey, director/editor of Satellite Pictures.

In today’s video, Michael Ramsden discusses the importance and meaning of mystery in the Bible. It does not come from ignorance, as the word is often used in modern times, but rather it is mystery born out of insight and wonder, one that is informed by understanding the world around us. As Ramsden notes, Jesus’ use of children to describe the nature of faith isn’t meant to emphasize their ignorance, but rather their sense of trust for those who love them. Likewise, we should not be afraid to search out answers, as if knowledge will lessen our faith in God. Rather we should trust that our explorations will only strengthen our understanding in Him.

Today's video is courtesy of filmmaker Ryan Pettey, director/editor of Satellite Pictures and features physicist Ard Louis.

In today's video, Oxford physicist Ard Louis discusses the famous debate between renowned evolutionary biologists Stephen Jay Gould and Simon Conway Morris. Gould believed (and wrote in his book Wonderful Life) that if the "tape" of evolution were rerun, the chance that anything like human intelligence would emerge is essentially zero. In other words, humanity is here through random accident. Gould pointed to the work of Morris and fellow scientists in their research of the Burgess Shale as evidence for this view.

However, Morris himself disagrees, pointing to what is called evolutionary convergence. As Morris notes, there are numerous examples of identical features evolving multiple times throughout the history of life independently. Morris believes that if the tape of life were replayed, we would see something like humans emerge. A Christian might say, it looks like we were planned.

Some Christians might find Simon Conway Morris' viewpoint, with its implicit teleology, more attractive. Others, perhaps motivated by a high view of providence, may find Gould's emphasis on contingency equally congenial to their faith. What do you think?

In our previous essay, we learned that a tree summarizing species relationships can be built using DNA information, and how we can use DNA as a “molecular clock” to date ancient events. Both of these methods have made specific predictions about the origin of whales. If evolution is true: whales are related to the even-toed hoofed mammals and should share common ancestors with them; transitional fossil forms dating from about 45 to 50 million years ago should be found which can be shown to be related to both the even-toed hoofed mammals and modern whales; whales are most closely related to modern hippos, and should share a common ancestor with them.

What other types of information might we be able to use to construct a phylogenetic tree (i.e. a family tree) of species relationships? It turns out that characteristics of body structure also can be used – for example, the presence or absence of certain bones, or the specific shapes of those bones. An advantage of using bony features is that they can be recovered from fossils, whereas DNA (with only certain limited exceptions) must come from living organisms.

We can also derive functional information from an examination of bony features. The various protrusions, bumps and knobs found on bones usually have important implications. For example, smooth rounded areas at the ends of bones allow them to fit together and move easily. The shapes of such surfaces determine which bone motions are “allowed” or “disallowed”. Consider, for example, the motion of the forearm against the upper arm at the elbow. This is a “hinge” joint, whose normal motion is defined by the shapes of the upper arm bone and one of the forearm bones, where they meet each other. You might normally exercise the action of this hinge joint when you pick up a cup of coffee, bring it to your mouth, then set it back down again. Let’s try to imagine another motion. For this exercise we first need to get our arm into the proper starting position. Place your arm at your side, bent at the elbow at a ninety degree angle, with your palm up. Now, while keeping your palm up, let’s attempt to move your arm only at the elbow (no shoulder motion – that’s cheating!). Now swing your forearm out to the side and attempt to end up with your fingers pointed directly away from your side. Most of you will not be able to do this. If you can, it’s because your shoulder is rotating in spite of yourself. This motion at the elbow is normally not allowed. Hence a careful analysis of bone shapes can allow us to infer how the bones were used. This in turn can assist us in the task of phylogenetic (evolutionary) classification of organisms. That is, we will have more confidence in the grouping together of animals in our tree diagram if corresponding bones are used functionally in the same way.

Therefore we would expect that we could use various bony features to help us examine the predictions generated by our previous look at different types of DNA data. Are there any bony features that are particularly relevant to the even-toed hoofed mammals? Well, it turns out that there are. These are mainly running animals, and there are several features of their ankle bones, which taken together define the “allowed” motions which make them efficient runners. If one takes the various ankle bones of a large group of mammals, examines them carefully to note their shapes, scores that information into a table, then uses a computer program to build a phylogenetic tree, it turns out that all the even-toed hoofed mammals are placed together. So far, so good. But what about whales? Well, now we have an obvious problem. Modern whales are very specialized, - they have flippers which correspond to the forelimbs, and they have almost no hind limbs! I say “almost” because they do have small pelvic bones, which are not attached to the rest of their skeletons. But they certainly have no ankles. This is where the fossils should come in – if evolution is true, we should expect to be able to identify transitional fossils which are ancestral to whales which contain the characteristic ankle bony features of the even-toed hoofed mammals.

Now let’s look at bony features from the whale perspective. We have already mentioned the almost complete loss of hind limbs, and the presence of forelimbs modified into flippers. In addition, as air breathers, whales have a blowhole at the top of their skull. And as powerful swimmers, which use a large tail fluke in vertical motions, whales have enormous sets of muscles which attach to enlarged projections from their vertebral column. So if evolution is true, we should begin to see fossil forms which manifest changes in bony features which correspond to the gradual accumulation of these whale-like characteristics. However, we still need more, because these various bony features all would be expected to occur in largely or exclusively aquatic forms. We might expect this to correspond to the later stages of a transition from terrestrial even-toed hoofed mammals. But what about the earlier stages? It would be very helpful if we had some “defining” characteristic of whales, similar to the ankle structure of even-toed hoofed mammals.

It turns out that the structure of the bones of the skull and ear apparatus of whales are highly modified to allow efficient hearing underwater. The mechanical aspects of efficiently receiving sound through water are somewhat different than receiving sound travelling through air. If evolution is true, we should expect to be able to find key transitional fossil forms with a progressive series of modifications of the skull and ear bones, features which would not be found in any other mammals.

Now that we know what we should expect to see, if evolution is true, let’s look at what has actually been found in the fossil record. Over the last fifteen years or so, a series of fossils, many of them discovered in the Indian subcontinent, have fulfilled nearly all of our predictions.^1,2 Let’s look at the figure below (Figure 1), reproduced from a recent popular book on evolution.³ This shows a series of fossils, arranged in approximate chronological order, with a modern whale at the top. How old are these fossil forms? The entire fossil progression illustrated occurs from a little over 50 million years ago to about 40 million years ago. So a remarkable alteration in general body form occurred in a little over 10 million years. This time frame agrees well with the previous prediction from the DNA “clock” that we discussed in our previous essay. Second, the general change in body shape corresponds to what we predicted in our discussion of whale bony features above. That is, there is a gradual elongation and streamlining, there is a modification of the forelimb into flippers and progressive reduction of the hindlimb, the nostrils for breathing move toward the top of the skull to form a blowhole (not obvious from the diagram), and the vertebrae develop enlarged projections to support the attachment of swimming muscles.

Figure 1: Skeletons and Body Forms of Modern Whales and Fossil Ancestors
The reconstructed skeletons (black) from modern whales (top) and various ancestral skeletal forms (series below) are in chronological order (from Pakicetus up). Indohyus is an extinct whale “cousin”. Relative body size, to scale, is indicated by the gray shapes at the right of each animal.

There is probably little question that the last fossil species in the figure (Durodon) is well on the way to becoming a modern whale. However, it might be argued by a skeptic that the earlier species (like Rhodocetus, Ambulocetus, or Pakicetus), despite the “cetus” (whale) part of their names, are not so obviously “whale-like” that they deserve to be considered as fossil whale ancestors. However, remember the characteristic whale skull modifications for hearing? It has been shown very clearly that throughout this series of fossil species, the various bony changes necessary to support efficient hearing in water were being acquired in a stepwise fashion. Organisms earlier in the sequence had skeletal characteristics consistent with them being able to hear well in both air (using the “classic” mammalian hearing apparatus), and newly acquired changes to also allow better hearing in water. Later organisms in the sequence become increasingly specialized for hearing in water only.⁴

What of the earliest fossil shown in this diagram –Pakicetus? Careful examination shows that it has the features we would predict for an early whale ancestor. It has the ankle bone characteristics of the even-toed hoofed mammals (in fact these features are also found in several of the later fossil forms as well, ensuring their continuity). This confirms one of the predictions made by the DNA evidence we discussed earlier. Furthermore, it has some of the modifications of the skull bones necessary for more efficient underwater hearing, which were previously documented only for modern whales and their later (more obvious) ancestors.⁴ These features are also shared with the “whale cousin” Indohyus.⁵ Preservation of more of the skeleton of this latter species has allowed detailed analysis indicating characteristics likely shared with whale ancestors. Indohyus was probably a wading animal, which spent much of its time in the water. It appears to have fed mostly on land, so it is suggested that resort to the water was made to escape predators.⁵

Finally, we need to look back at the last prediction from our previous DNA evidence, namely that modern whales are most closely related to hippos. If evolution is true, we should expect to find fossil forms linking these two modern groups. This has proven to be a tougher nut to crack, mainly because the ancestral whales first appear about 50 million years ago in what is now south Asia, and the hippo family first appears about 15 million years ago, in Africa. The most recent tree diagram, produced by using a combination of skeletal features and DNA data, still supports this family connection, as shown by the following figure (Figure 2).⁶

Figure 2: Phylogenetic Tree Showing the Relationship of Modern Whales to Living and Extinct Even-Toed Hoofed Mammals
This tree is based on both bony features and DNA data. The organisms presented in blue are semi-aquatic or aquatic forms. Organisms shown in green are terrestrial even-toed hoofed mammals (Artiodactyls). In black is shown a member of the odd-toed hoofed mammals. In red is an extinct fossil ancestor group. (This figure is adapted from Fig 1a in Reference 6).

The blue lines in the diagram show species in which the skeleton is specially thickened, and the bone structure more dense. This is an adaptation which allows wading animals (like modern hippos and the fossil Indohyus) to be good “bottom-walkers” (it prevents them from floating due to lighter body tissues), and allows fully marine organisms (like modern whales) to have “neutral buoyancy” (so they don’t always tend to pop up to the water surface, like a cork). There has also been progress in clarifying the relationships between fossil ancestors of hippos and those of modern whales. A recent study of hippo evolution, based only on skeletal characteristics, has conclusively shown that the hippo family are descended from an extinct group of fossil Artiodactyls, known to go back more than 40 million years, and whose fossils are from southern Asia. Furthermore, this study produced a phylogenetic tree predicting that this extinct hippo ancestor group also shared a common ancestor with the fossil whales.⁷ Thus the investigation of hippo origins is independently leading us back toward the origin of whales. However, in this study the statistical support for predicted common ancestor of the ancient hippo group and the ancient whale group is not as strong as scientists would like to consider this “case closed”. What is necessary is more fossils, of the appropriate age in order to complete the story of hippo evolution. We still need that to fill in the details of the predicted relationship of hippos to modern whales.

Thus the “Whales’ Tale” is not yet complete. It is a story of scientific discovery in progress. As we finish, let’s briefly summarize what we have found out. Different types of DNA evidence agree that modern whales are most closely related to the even-toed hoofed mammals, despite the obvious great changes in limb anatomy of the modern whales. This prediction has been amply confirmed by the fossil record. The DNA sequence evidence predicted a time frame during which critical early events in evolution of whale ancestors should occur. This prediction has also been amply confirmed. Finally, DNA evidence predicts that modern whales are most closely related to hippos. There is some fossil evidence supporting a predicted common ancestor, but more data is needed. A final caution to possible sceptics – this state of “unfinished business” is precisely how the scientific process works. There is no “crisis”. There is no indication that evolution is not true. There is simply the ongoing work of mapping out of various lines of evidence. A scientific conclusion is considered well supported if “all roads lead to Rome”. In the case of whale evolution it might be prudent to say that the evidence has not quite converged in Rome yet, but that we are now in the suburbs. That is precisely what makes science interesting and fun. Stay tuned!

The next blog in this series can be found here.

References:

1: Thewissen J.G.M., Williams E.M., Roe L.J. and Hussain S.T. 2001. Skeletons of terrestrial cetaceans and the relationship of whales to artiodactyls. Nature. 413: 277-281.

2: Gingerich P.D., ul Haq M., Zalmout I.S., Khan I.H., Malkani M.S. 2001. Origin of Whales from Early Artiodactyls: Hands and Feet of Eocene Protocetidae from Pakistan. Science. 293:2239-2242.

3: Coyne, J.A. 2009. Why Evolution is True. Viking Penguin, New York. Pg 50.

4: Numella S., Thewissen J.G.M., Bajpai S.,Hussain T., Kumar K. 2007. Sound Transmission in Archaic and Modern Whales: Anatomical Adaptations for Underwater Hearing. The Anatomical Record. 290:716-733.

5: Thewissen J.G.M., Cooper L.N., Clementz M.T., Bajpai S., Tiwari B.N. 2007. Whales originated from aquatic artiodactyls in the Eocene epoch of India. Nature. 450:1190-1194.

6: Geisler J.H. and Theodor J.M. 2009. Hippopotamus and whale phylogeny. Nature. 458:E1-E4.

7: Boisserie J.-R., Lihoreau F., Brunet M. 2005. The position of Hippopotamidae within Cetartiodactyla. Proceedings of the National Academy of Sciences U.S.A. 102(5):1537-1541.

Though some may believe that moving the science/faith dialogue forward is best left to scientists, scholars, and theologians, we at BioLogos recognize that our pastors play an invaluable role in the conversation. Across the globe, pastors are helping their congregations work through difficult issues of science and faith with honesty, insight, and a gentle spirit. To this end we present an ongoing series recognizing sermons (and the pastors who give them) that are helping to promote the harmony of science and faith. Today's sermon comes from Rev. Tim Keller, pastor of Redeemer Presbyterian Church. Click above to hear an excerpt. Below, is a brief summary written by BioLogos editorial staff. The full sermon can be downloaded here.

In tracing the story of the Bible, Dr. Keller’s previous sermons examined the early chapters of Genesis, which relate the events that lead to humanity’s fall from right relationship with God. Currently, he is exploring God’s redemption of the human brokenness in Paul’s epistle to the Romans. This particular message focuses on chapter two where the Apostle Paul exposes the hypocrisy of Law-observing Jews: while they judged Gentiles by the standard of the Law, they themselves failed to fulfill its requirements. He also asserts that outward performance of the Law by no means exempts them from God’s judgment or from the disease of Sin, which entered the human heart at the Fall. Keller affirms, therefore, that all are in need of a “regenerate new heart” through Jesus Christ, who perfectly fulfilled the requirements of the Law and who alone is able to accomplish this transformation through the power of his cross.

Paul’s message first illuminates what Keller identifies as the failure of religion. The church in Rome no doubt consisted of both Gentiles and Jews. With this in mind, Paul speaks to both groups. Up to this point, Paul has been highlighting the idolatry of the Gentiles. He then reorients his focus in Romans 2 to address the Jews, who were likely to stand in judgment of their gentile brothers and sisters because of the Jewish Law. He declares in verse one, “You, therefore, have no excuse, you who pass judgment on someone else, for at whatever point you judge another, you are condemning yourself, because you who pass judgment do the same things.” Keller explains that this statement exposes the hypocrisy of the religious who look to observance of an outward behavioral code for justification rather than to grace through Jesus, which leads to an inward observance of the Law. For example, although Law observers did not bow before physical graven images as the Gentiles did before faith in Christ, idols occupied their hearts. These inner idols, for both the religious Jews and present Christians, could take the form of power, career, achievement, etc. All in all, Paul demonstrates that religion fails since neither the moral nor the immoral person is perfect by God’s standards. Dr. Keller sums up this point nicely with this statement: “I’m not okay, you’re not ok.” There is not one person who measures up to the standard of the Law of God, and not one person, therefore, has a right to pass judgment according to it.

Dr. Keller then discusses why no one can measure up to the terrible beauty of God’s Law “no matter how good” one’s actions may be. Primarily, it is because the standard is not focused on performing the right deeds. Rather, the major sins described by Paul in Romans 1 include greed, insolence, heartlessness, etc. Although actions accompany such characteristics, they begin as inner attitudes of the heart. Often people read God’s ordinances at the behavioral level, as the religious Jewish people did, in an attempt to justify themselves as a moral person, but God’s requirements are much more demanding. This is revealed in Jesus’ Sermon on the Mount, for example, when he examines the Ten Commandments. He says in Matthew 5: 21-22 (NIV), “You have heard that it was said to the people long ago, ‘You shall not murder, and anyone who murders will be subject to judgment.’ But I tell you that…anyone who says to a brother or sister, ‘Raca,’ is answerable to the court.” In using the Hebrew word ‘raca’ meaning ‘nobody,’ Jesus is revealing that the sin of murder is birthed from a heart that devalues another person who is infinitely valuable in God’s eyes. Simply put, the Law of God is after a certain type of person whose right actions flow from a right heart. For example, the Law points to a person so filled with God’s love that they not only refrain from murder, but rather treat others as royalty. Keller continues as he explains the impossibility of such a standard for a human being, yet the Law demands it. What is more, people will demand a similar standard of others. Keller also emphasizes the Day of Judgment. Because God is just, he will hold a person accountable to either the standard of grace or to the standard that one person required of another. No person is perfect, and therefore, none will be able to stand in either God’s judgment or the judgment of their own heart. This creates the need for a transformed heart as Dr. Keller expounds in the final point of this passage.

In the last verses of Romans 2, the Apostle Paul relates the “failure of religion because of the terrible beauty of the Law” to the need for a regenerate heart. This is only possible through the circumcision of the heart in Christ by the Holy Spirit. Keller first explains the significance of circumcision. Circumcision was a physical distinction between the pagan cultures and the Jewish people who were in covenant with the God of Israel. On a deeper level, this act symbolized the consequence of disobedience to the covenant first established between Abraham and God: one would be cut off from the covenantal relationship with God. As Dr. Keller explains, all people have fallen short of the Law. For this reason, God sent Jesus, his son, to fulfill the requirements of the Law. He then died on the cross to receive upon himself the consequence of death that all deserved. Therefore, Paul argues that it is no longer one who receives physical circumcision who is saved, but one who receives the circumcision of the Spirit in Christ. Romans 2:28 (NIV) establishes this point saying, “A person is not a Jew who is one only outwardly, nor is circumcision merely outward and physical. No, a person is a Jew who is one inwardly; and circumcision is circumcision of the heart, by the Spirit, not by the written code.” Finally, Dr. Keller explains the significance of the Old Testament Law: the perfect standard describes not a moral code, but our Savior Jesus Christ. Ultimately, one seeks to obey the beautiful Law which Jesus embodied, yet one receives grace in the times of failure, confident that Christ has indeed paid it all.

In today’s video, Pastor Brian McClaren discusses the idea of the “slippery slope”. As he notes, the metaphor itself is problematic, because we often assume that we are on the top of the slope to begin with, when in fact changing our views may help us ascend the slope, or to reach a new peak of understanding on the other side.

He also notes two dangers that face the science and faith dialogue. On one side is excessive confidence, when we are so sure of being right that we refuse to consider other ideas. But being too afraid of excessive confidence can lead to an insufficient confidence, where we feel incapable of knowing anything for sure. McClaren proposes that what Christians need, rather, is proper confidence, the confidence that we are moving ahead yet still willing to learn. This, he says, is what it means to be a disciple: to be interested in the truth and always learning, but always willing to be pensive again rather than set in our current knowledge.

Though some may believe that moving the science/faith dialogue forward is best left to scientists, scholars, and theologians, we at BioLogos recognize that our pastors play an invaluable role in the conversation. Across the globe, pastors are helping their congregations work through difficult issues of science and faith with honesty, insight, and a gentle spirit. To this end we present an ongoing series recognizing sermons (and the pastors who give them) that are helping to promote the harmony of science and faith. Today's sermon comes from Rev. Tim Keller, pastor of Redeemer Presbyterian Church. Click above to hear an excerpt. Below, is a brief summary written by BioLogos editorial staff. The full sermon, which we highly recommend can be purchased from Redeemer’s sermon store. Finally, if you know a sermon or podcast related to science and faith that has especially spoken to you, please let us know.

In the Garden of Eden, Eve is tempted to put her own desires ahead of God’s call for her life. The serpent tells her that if she eats of the fruit she can become like God: she, in essence, can become the master of her own fate. Similarly, as the New Testament begins, Satan comes to Jesus and tempts him in three different ways to become centered in self, rather than centered in the Father. Finally, Paul begins his great treatise, his letter to the Christians in Rome, with the same thought. We all, like Eve, but not like Jesus, have tasted of the fruit, and Dr. Keller in his penetrating style expounds.

This week’s sermon continues to evaluate the heart of humanity, which first is revealed in Genesis, and later is expounded upon in Romans 1: 18-32. The Apostle Paul’s letter to the church in Rome presents a clear picture of both God’s revelation in the world, and humankind’s suppression of the truth. Exploring the message of Paul, Dr. Keller reveals that within each heart is the knowledge of our God, the factory of our idols, the hardening of our humanity, and the capacity for endless praise.

Foremost, the knowledge of God resides deep in the soul, but humans continually suppress this truth. It is the knowledge that God is Creator to whom all are completely accountable and on whom all are forever reliant. However, as Paul reflects on humanity in Romans 1: 21 (NASB), he claims that “though they [people] knew God, they did not honor Him as God or give thanks…” Dr. Keller explains that an unthankful heart is not merely bad etiquette; it generates the false reality of self-sufficiency and fails to recognize utter dependence on God for all things. Our sinful nature desires to maintain control, but true acknowledgment of God demands that we submit to his will rather than our own. Keller further makes the point that many people can believe in an impersonal God who gives all a free pass into heaven, but very few people wish to believe in the relational God of the Bible who demands all of their soul. For this reason, people suppress the truth about God and withhold his praise.

Inevitably, this act of turning away from the truth of God leads to the manufacturing of idols within the heart as one begins to worship a created thing rather than the Creator. Dr. Keller explains that people are “telic,” which means that they “need to live for something.” There is something in every person’s life that holds their worth, hope, and allegiance. If this something or someone is not the living person of Jesus Christ, one will be enslaved to idols. From wealth to marriage to morality, the Apostle Paul makes it clear throughout all his letters that these idols may take numerous forms. For example, he says in Romans 1:23 (NASB) that they “exchanged the glory of the incorruptible God for an image in the form of corruptible man and of birds and four-footed animals and crawling creatures..” The stark reality is this: God deserves all of our love and all else is futile worship of idols.

Next, the sermon explores how the worship of idols causes the heart to harden. Dr. Keller explains how idolization will ultimately strip a person of his or her humanity. In speaking about this very thing, the writer proclaims the truth in Psalm 135 (NASB) that idols are “the work of man’s hands. They have mouths, but they do not speak; they have eyes, but they do not see; they have ears, but they do not hear…Those who make them will be like them, Yes, everyone who trusts in them.” It is apparent from this verse that an idol will consume the heart’s desire. In this place, the person’s will becomes utterly subject to the object and conformed to its dead image, rather than conformed to the image of the living God.

Lastly, Dr. Keller illuminates the remedy for all the perpetual idols in our hearts. He affirms that in order to stop worshipping these idols, one must do as the angels do in heaven: endlessly praise and worship God. He then references 1 Peter 1: 10- 12, which describes how angels long to look into the things concerning the gospel of Jesus Christ. In other words, Dr. Keller explains, the angels deeply desire to gaze upon the beauty of what Christ has done for all humanity by his death on the cross and resurrection from the grave. When we too see Jesus and glorify him as the One who gave it all for us, we will finally be saved from the destructive power of idols.

In the rest of the series, we will look closely at the evolutionary explanation for the blueprint. That explanation postulates that tetrapod limbs arose during a particular era in life's history, and that they arose as modifications of the fins of fish. And the evolutionary explanation isn't just an interesting idea. It's a comprehensive explanation – it helps us to understand bones, fossils, genes, chemical signaling systems. It provides a coherent framework for understanding why limbs are the way they are, and how they got that way.

Comparing the anatomy of tetrapod vertebrates and fish

The idea that tetrapods arose from fish is not new; E.D. Cope proposed in 1892 that tetrapods descended from lobe-finned fish. (Modern lobe-finned fishes include coelacanths and lungfish, and comprise one of two divisions of the bony fishes. The other division, the ray-finned fishes, includes most familiar kinds of fish.) In the early days, biologists inferred ancestral relationships between species largely through comparative anatomy and embryology: they would carefully classify organisms according to their structure (including their structure during development) and look for relationships that generated nested hierarchies. A simple nested hierarchy goes something like this: 1) animals with backbones; 2) animals with backbones and limbs; and 3) animals with backbones, limbs, and hair. Animals in group 3 also belong to groups 1 and 2, while animals in group 2 also belong to group 1, and so the groups together define a nested hierarchy. Such studies alone could have led some scientists to infer an ancestral relationship between fish and tetrapods, and perhaps those studies did convince them. But then there were fossils of various types of fish and other vertebrates, many long extinct. That fossil record was relatively sketchy in 1892, but it nevertheless led Cope and others to conclude that certain fish had given rise to tetrapods at a particular time in natural history.

The fossil record shows a fish-to-tetrapod transition

Here are some basic findings from the fossil record that suggest a fish-to-tetrapod transition and that have been known for decades:

• Fish, including fish with bones, lived on the earth before tetrapods appeared. Specifically, fossils of bony fish first appear in rocks from about 420 million years ago.

• Tetrapods appear in the fossil record at a particular point in history and then persist and diversify in subsequent eons. Their arrival was long thought to have occurred about 365 million years ago, although some recent findings have challenged that hypothesis.

• Tetrapods that still had some fishy features were prowling the planet 365 million years ago.

• Lobe-finned fish that were starting to look more like tetrapods were eating other fish about 385 million years ago.

Even many decades ago, there were hints that something interesting happened between 400 million years ago and 365 million years ago. Let's take a close look at the ancient animals that suggest the fish-to-tetrapod transition.

Ancient animals

The most primitive known tetrapods for which we have skeletal remains lived 365 million years ago. They were undeniably tetrapods, but there was definitely something fishy about them. (Heh heh.) One of the most famous of these creatures is Acanthostega, discovered in 1987 by British paleontologist Jennifer Clack and pictured below. Acanthostega is a card-carrying tetrapod, with fingers and toes. But it has a fish tail, with fin rays. Another well-known primitive tetrapod is Ichthyostega, which lived around the same time as Acanthostega. Like Acanthostega, it is a true tetrapod, but has several odd fish-like structural features. For example, its skull is more fish-like than that of Acanthostega. In summary, both Acanthostega and Ichthyostega already used the limb blueprint, even though both also had some fish-like anatomical characteristics. Their presence 365 million years ago shows that tetrapods must be at least that old, and their mixture of anatomical features suggests that the transition happened not long before that.

And what about the lobe-finned fish that looked a bit tetrapod-ish? That animal is Panderichthys, described as “vaguely crocodile-shaped” with skeletal features that were tetrapod-like. Specifically, this ancient fish had tetrapod-like “shoulders,” and recent analysis found some finger-like bones at the ends of the fins. The creature also had a breathing hole on the top of its head. These fish lived around 385 million years ago.

The hunt for the earliest tetrapods

Taken together, these observations suggested that the fish-to-tetrapod transition occurred between 385 and 365 million years ago. Eager to see what that transition looked like, scientists began to look for 375 million-year-old rocks in which they might find animals at the beginning of tetrapod-hood. They wanted to catch evolution in the act.

Let's stop and think about this, because it's cool and because it's important to note the extent to which evolutionary biology is hypothesis-driven. Critics of evolution sometimes portray the theory as an untestable historical conjecture, depicting it as fundamentally different from experimental science in the lab. But the hunt for the earliest tetrapods was an effort to test a hypothesis that had generated a prediction. Based on the hypothesis that lobe-finned fish were ancestors of tetrapods, scientists predicted that intermediate animals, “fishapods,” would be found in the gap between Panderichthys and Acanthostega. To evaluate the prediction, all they needed to do was find some suitable 375 million-year-old rocks.

Neil Shubin describes that search in the first chapter of Your Inner Fish. He and his colleagues found suitable rocks in the islands of the Arctic: the right age, nicely exposed (by erosion), and representative of the kind of environment that their quarry would frequent – freshwater streams. They made their biggest discovery on their last trip (“a do-or-die situation”) in 2004. That discovery was Tiktaalik roseae, the “fishapod.”

The “fishapod”

Tiktaalik roseae is one of the most extraordinary fossil intermediates ever described, and its public debut in 2006 was front-page news. An artist's conception of the animal is pictured below.

There are several aspects of the anatomy of Tiktaalik that earn it the title “fishapod.” Like a good fish, it had scales and webbed fins. Like a tetrapod (more specifically, like a crocodile), it had a flat head, with eyes on the top of the head, and it had a neck. But what about those fins? Or are they limbs? Remarkably, the answer seems to be, “both.”

The fins of Tiktaalik were part fish fin, part tetrapod limb. On the outside, they looked like fins, with webbing. On the inside, though, these fins were clearly tetrapod-like. Amazingly, the fins of Tiktaalik were built using a primitive version of the limb blueprint: one bone, two bones, blobs, digits. As Shubin writes in Your Inner Fish, “We had a fish with a wrist.” (The Tiktaalik roseae web site at the University of Chicago is a great source for images and more information.)

Let's address three questions about Tiktaalik that might have occurred to you. First, why might animals like Tiktaalik have developed tetrapod-like fins? Shubin and his colleagues suggest that these limb-like fins may have been useful for doing “push-ups” in the shallow water. (Like Panderichthys, Tiktaalik had a breathing hole on top of its head and was clearly adapted for living and moving in shallow water.) Second, is Tiktaalik an ancestor of all tetrapods? No, not necessarily. What Tiktaalik shows us is that animals were developing tetrapod features in the context of fish bodies, and Tiktaalik shows us the context (shallow water) in which this likely occurred. But that doesn't mean that our lineage arose from Tiktaalik itself. Finally, is Tiktaalik now the oldest tetrapod? No, apparently not. For one thing, Tiktaalik is truly transitional, and probably therefore not worthy of full tetrapod membership. But more notably, data published in 2010 show that tetrapods are a lot older than was thought at the time of Tiktaalik's discovery. The new findings show footprints that are unmistakably those of a tetrapod, in rocks about 395 million years old. Surprisingly, then, tetrapods were already on their way long before Neil Shubin's specimen lived. Tiktaalik is truly a fish/tetrapod intermediate, which was living at the same time as animals that were fully tetrapods. A simple story of succession, in which intermediates disappear and are replaced by less intermediate types, seems to be an oversimplification.

In conclusion, the fossil record provides evidence that the fins of fish and the limbs of tetrapods are related by ancestry: limbs seem to be modified versions of fins. What other evidence supports this proposal? In the next post, we will turn to developmental biology, and explore the meaning of the term 'homology.'

Further reading:

Neil Shubin (2009) Your Inner Fish: A Journey Into the 3.5-Billion-Year History of the Human Body. New York: Vintage Books.

Carl Zimmer (2006) A Fin is a Limb is a Wing: How Evolution Fashioned its Masterworks. Online at NationalGeographic.com.

Tiktaalik roseae website at the University of Chicago.

Jennifer Clack's website at the University of Cambridge.

Images are from Wikipedia.

The ordained and blessed tradition of marriage is established in Genesis 2: 18-25. This passage communicates important ideas, Dr. Keller affirms, about both marriage seeking and marriage executing. When considered, these concepts will allow one to be successful in both areas.

Foremost, Adam’s response to his wife highlights marriage’s potential to be idolatrous. When God presents all other creatures before Adam in the garden, not one is considered to be a suitable helper. Therefore, the Lord creates Eve from the rib of Adam and brings her to him. Upon seeing the woman, Adam exclaims in verse 23, “This is now bone of my bones, and flesh of my flesh.” Adam is expressing, in effect, that he has found at last the helpmate he longed for—by discovering Eve, he is finding himself. Marriage, then, is so fulfilling that there is a danger of idolization of one’s partner. Often, the temptation is to receive love, affirmation, respect, and even a foundation in life from their spouse, rather than from God—the very source of all these things. However, no human relationship “can bear the weight of those expectations,” and the marriage will be crushed. In addition, there is a tendency for unmarried persons to commit idolatry when they either yearn for marriage to complete them or search for that “perfect” marriage partner. God alone can meet these desires for perfection and wholeness. The problem, then, is not in loving one’s spouse too much or in wanting a blissful marriage, but in the smallness of one’s love for God in proportion to the other.

Next, God’s identification of Eve as Adam’s helper reveals the long-enduring patience that marriage requires. This word helper is often used to refer to military reinforcements throughout the Bible. The man and the woman as a couple bring to each other a strength that is not had by either of them as individuals. However, they are not just helpers, but suitable helpers. The word suitable in the Hebrew, Dr. Keller explains, is closely translated to mean ‘like opposite.’ In other words, the woman is like him, yet not him. Like two puzzle pieces, Dr. Keller says, God designed male and female as perfect complements to one another. Thus, marriage involves two people coming together with equal, but distinct strengths, and they enter into a tight relationship. So close is this communion that it is described as becoming “one flesh” in Scripture. In this closeness, necessary “head-butting” occurs as the spouses are challenged by one another to become the persons God made them to be. For this reason, it is essential to have the patience to bear with one another throughout this long journey of growth in life.

Then, there is a supernatural humility in the idea of marriage as conveyed by Genesis 2: 18(NASB) when God says, “‘It is not good for the man to be alone.’” Although Adam is in Paradise with God himself, God seems to indicate that Adam is lonely. According to Dr. Keller, the only explanation is that God specifically made Adam to need someone else in addition to himself. This is the most humble, unselfish act one could imagine—that the God of the universe would make people to need others as well.

As Dr. Keller concludes his sermon, he discusses how marriage portrays the relationship God seeks with his people—God as the bridegroom and his people as the bride. It is essential to understand that God desires to be the intimate helpmate to every person, even their spouse who is faithfully committed to their growth. Without God, one will never become who he or she was created to be. In claiming to be his people’s husband, as in Isaiah and Jeremiah, God is saying, “I have given you my heart.” For this reason, God sent his only son, Jesus Christ: to win back the heart of his wayward bride. Therefore, those who accept his love and put on the wedding ring of faith inherit all that is found in Christ. Ultimately, the Bible begins with a wedding, and it ends with a wedding—the marriage supper of the Lamb that will fill the world with the children of God.