Book Review: Why Evolution is True

Why Evolution is TrueWhy Evolution is True
by Jerry A. Coyne
Penguin, 2009
282 pages (paperback)


Science and religion have had a love-hate relationship.  Like your average sitcom, the “will they?/won’t they? get together for good” question remains unresolved, and so we keep tuning in hoping that this week it will finally happen.

In the 16th century, John Calvin wrote in his Institutes of the Christian Religion that despite all the regularity of the seasons, the unpredictability of them—a frozen spring or a warm winter—“are so great and so unequal as to make it very apparent that every single year, month, and day, is regulated by a new and special providence of God.”  In other words, unexplainable weather patterns had to be immediately attributed to a special divine act.  Today we know the scientific reasons behind such unpredictability, even when they throw my Weather Bug app a surprise or two.

Similarly, in the 18th century, the Puritan minister, Cotton Mather, speculated on the nature of gravity.  Many theologians ultimately supplanted the natural world with the divine being itself, leaving a point at which the natural world disappeared and only the divine nature was left.  “The Gravitation of Bodies is One of them; For which No Cause can be assigned,” concludes Mather, “but the Will of the Glorious GOD, who is the First Cause of all.” Two centuries later, Einstein provided the General Theory of Relativity, which changed our understanding of the nature of gravity altogether.

And in Einstein’s day, his discoveries were also controversial, receiving significant challenges from theologians, yet without Special Relativity, GPS satellites could not compensate for time dilation and their accuracy would be compromised.

So let me just say it: the limits imposed by theologians on science has historically proven to be arbitrary, problematic, and short-sighted.

When I read such an intense distrust of science on blogs whose very existence could not occur without the advances of quantum physics, the irony is not lost on me.  One can listen to a sermon against scientists on an iPod, which itself could not exist without the discoveries in magnetism that lead to a Nobel Prize in 2007.

And so what about evolution?

In Why Evolution is True, Jerry A. Coyne gives a fantastic overview of the evidence behind evolution.  I first came across the book when reading a review of it in New Scientist a year ago, but I finally took it off my TBR and read it. I was not disappointed.

There are many factors that can go into a person’s rejection of evolution, many of which are theological in nature.  The special creation of human beings based on a fairly literal reading of Genesis 1-2 often trumps (for certain Christians) anything offered by biologists in the area of human evolution.  Couple this with a sort of evolution on demand—that is, the human desire to see the human species change overnight into something different as proof of evolution’s veracity—and you have a recipe for rejection.  Evolution just doesn’t occur that way, though T.V. shows like Heroes leads us to think it does.

The fact that many human beings refuse to believe that they are indeed naked apes—often based on what appears to the lay person to be little change in the species over recorded history—is not lost on Coyne.  What he does to help the reader wrap his or her head around the problem is provide a perspective on time itself and back it up with the physical evidence.

Humans are newcomers on the scene—our lineage branches off from that of other primates only about 7 million years ago, the merest sliver of evolutionary time.  Various imaginative analogies have been used to make this point, and it is worth making again.  If the entire course of evolution were compressed into a single year, the earliest bacteria would appear at the end of March, but we wouldn’t see the first human ancestors until 6 a.m. on December 31.  The golden age of Greece about 500 BC, would occur just thirty seconds before midnight.

When the average life-span of a human being is compared to the age of the earth, we have as much of a perspective of time as the mayfly does of our 24-hour day.  Here is another irony.  Theologians often warn the Christian that God is infinitely greater and older than we small worms, so we humans should be wary of rejecting something simply because our pitiful minds cannot grasp the infinite.  Perhaps that lesson should be carried over to the discussion of evolution and our limited ability as mayflies to understand the time-frame required for new branches on the tree of life to form.

But isn’t evolution just a theory?

Coyne’s book offers several great chapters on what goes into the evolutionary process.  He looks into several factors leading to evolutionary change, including natural selection, genetic drift, sexual selection, etc.  He begins with definitions, handling misconceptions of evolution, for example, that it is simply an accident or the dismissive “it’s only a theory” mantra, meaning (as some intend) that it is simply speculation without evidence.  As to the first, natural selection, Coyne demonstrates why it is not simply an accident.

True, the raw materials for evolution—the variations between individuals—are indeed produced by chance mutations.  These mutations occur willy-nilly, regardless of whether they are good or bad for the individual.  But it is the filtering of that variation by natural selection that produces adaptations, and natural selection is manifestly not random.  It is a powerful molding force, accumulating genes that have a great chance of being passed on than others, and in so doing making individuals ever better able to cope with their environment.

Take the appendix, for example.  It is an organ which likely served to provide bacteria during days before we cooked our food.  We’ve discovered that removing the organ does more good than harm.  Appendicitis can kill, which is why we remove them so often. Coyne notes that “before doctors began to remove inflamed appendixes in the late nineteenth century, mortality may have exceeded 20 percent.”  The appendix is a strange organ, and its size and location can vary significantly—a few people are even born without one.  If the medical world had not made it a practice of taking them out, it is possible that those born with appendixes would eventually be weeded out of the gene pool through death, leaving only those born without the bothersome organ.  This is, as Coyne says, “strong natural selection.”

As to the second, that evolution is speculation, Coyne raises several examples, such as atomic theory, which since World War II is hardly speculation, even though we never actually photographed an atom until decades later.  A theory is scientific, reminds Coyne, if it is “testable” and can “make verifiable predictions.”  Atomic theory is a theory, but it has made verifiable predictions and therefore it is not speculation.

But what about the evidence?

Coyne engages a large selection of evidence, fossil and otherwise, and if your reading habits include popular science magazines, much of it will be familiar.  My favorite recent discovery, Tiktaalik, is a prime example.  In 2004, scientists found Tiktaalik—a fossil of a transitional creature between fish and amphibian. It was a creature that had (among its many transitional attributes) both gills and lungs (see video below).

Perhaps the most intriguing chapter on Why Evolution is True was “Remnants: Vestiges, Embryos, and Bad Design.”  Like “ancient texts,” writes Coyne, “organisms are palimpsests of history—evolutionary history.  With the bodies of animals and plants lie clues to their ancestry, clues that are testimony to evolution.”

Vestigial features are those that “make sense only as remnants of traits that were once useful in an ancestor.”  A vestigial organ may still have some functionality, but it is considered vestigial because “it no longer has the function for which it originally evolved.”  However, these original features are occasionally reawakened to produce what is called an “atavism.”

A striking example of such a vestigial trait is that of the human tail, the coccyx, a left-over attribute from our primate ancestors (which were also traits from earlier ancestors). The coccyx is that “the triangular end of our spine that’s made of several fused vertebrae hanging below our pelvis,” says Coyne.

Tellingly, some humans have a rudimentary tail muscle…identical to the one that moves the tails of monkeys and other mammals.  It still attaches to our coccyx, but since the bones can’t move, the muscle is useless.  You may have one and not even know it.

These vestigial features are atavistic when there is still enough genetic material for the body to attempt to grow an actual tail. These tails are sometimes developed enough to be as long as a foot.  These types of carry-overs are most evident in the embryonic stage of human development.  As Coyne writes:

early in development human embryos have a sizable fishlike tail, which begins to disappear about seven weeks into development (its bones and tissues are simply reabsorbed by the body).  Rarely, however, it doesn’t regress completely, and a baby is born with a tail projecting from the base of its spine.

Doctors generally remove them, but in some places around the world the baby’s tail is kept and, as has apparently happened in recent memory, he or she is worshiped as a reincarnated god.

Whales also have similar features.  They are among the mammals that returned to the sea in their evolutionary process.  Whales are often born with vestigial pelvises and hind leg from their days as land animals.  The hind leg is underdeveloped, detached, and embedded in the flesh.  A small number have enough genetic material that a larger hind leg is developed and “protrudes outside the body wall.”

These limbs show all degrees of refinement, with many of them clearly containing the major leg bones of terrestrial mammals—the femur, tibia, and fibula. Some even have feet and toes!

Just as an aside, there are many other examples of this sort of thing.   Birds are related to reptiles, so it should be no shock when we find chickens that occasionally grow reptile teeth (see “Surprise, Chickens Can Grow Teeth“).

Despite these obvious throwbacks to previous evolutionary stages, many Americans are still not convinced.  This is, in large part, the result of a fundamentalism that still remains in this country, particularly one that is skeptical of science and insists on a particular, literal reading of Genesis.

By insisting that Genesis’s creation accounts needs to fit a modern cosmology—an approach John Walton calls “concordism” in his book, The Lost World of Genesis One—modern science is retrofitted to support an ancient cosmology (see my review here).  What is produced is an ancient text that no longer communicates and a modern science that no longer accurately represents the natural world.  In other words, those who insist on a certain interpretation of Genesis have actually does injustice to it and science.  Walton’s book is a corrective to this thinking, calling the reader to appreciate the culture and science of the ancient near east and to let modern science be science.

There are winds of change in the air for Christians.  While no naturalist wants to see science accommodated to religion, they will have to get used to a growing number of younger Christians who are not afraid of letting science describe the world.  The idea that ancient peoples did not see the world the way we do today is acceptable and, for them, staying true to both science and the world of the Bible.

monkeytownLike Walton, younger evangelicals are appearing to embrace what appears to be clear—evolution is true. Rachel Held Evans, the author of Evolving in Monkey Town, which recently made national news, is just one example of this.  “My generation of evangelicals is ready to call a truce on the culture wars,” says Evans. “It seems like our parents, our pastors, and the media won’t let us do that. We are ready to be done with the whole evolution-creation debate. We are ready to move on.”

Moving on may not be that easy.  Creationist Ken Ham immediately challenged Evans on his blog, noting that there are many who are still standing “uncompromisingly and unashamedly on God’s authoritative Word,” or to be more exact, on Ham’s approved interpretation.

So, while many Christians remain open to modern science, it may be a while before the entire discussion evolves into something that has outgrown fundamentalism.

In the meantime, I’d recommend Coyne’s Why Evolution is True as a primer on the science behind the controversy.  At 282 interesting pages (which includes a short glossary), it is a fantastic overview and basic education on what scientists mean when they say that evolution is true.  I’m sure that for many ignorance is bliss, but we should also remember that it is a recipe for bad science.

  • Kevin

    Good review. I enjoyed this book as an overview of the theory of evolution. I think it was interesting that in his last chapter he leaves room for something outside the domain of science (p. 225, halfway down). It is interesting because other atheistic evolutionists (aka Dawkins) don’t seem to do likewise. I think that this (Dawkins, et. al) perspective only produces more militant fundamentalism to “fight” evolution. One thing that is needed to remedy this problem is a perspective such as Coyne starts to give (although he probably doesn’t go far enough in that he suggests we only “make” our own purpose – p. 231).

  • Glad you liked it. He does leave purpose and morality open to something outside of science itself, which is interesting, but he is likely considering this to be the realm of philosophy or something like that. You might find Dawkins’s comments on moral philosophy interesting at this BigThink video.

In search of belief changing ideas