Evolution Is Only a Theory

Well, its only a theory. It is a scientific theory only, and it has in recent years been challenged in the world of science and is not yet believed in the scientific community to be as infallible as it once was believed.

—presidential candidate Ronald Reagan, addressing a group of evangelicals in Texas in1980 regarding Darwinian evolution

The implication in that statement is that there is something not quite right about a theory—that it is a mere speculation, and very likely wrong. Indeed, the everyday connotation of “theory” is “guess”, as in, “My theory is that Fred is crazy about Sue”. But in science the word “theory” means something completely different, conveying far more assurance and rigor than the notion of a simple guess.

According to the Oxford English Dictionary, a scientific theory is “a statement of what are held to be the general laws, principles, or causes of something known or observed.” Thus we can speak of the “theory of gravity” as the proposition that all objects with mass attract one another according to a strict relationship involving the distance between them. Or we talk of the “theory of relativity”, which makes specific claims about the speed of light and the curvature of space-time.

In science, a theory is much more than just a speculation about how things are: it is a well-thought-out group of propositions meant to explain facts about the real world. “Atomic theory” isn’t just the statement that “atoms exist”; it’s a statement about how atoms interact with one another, form compounds, and behave chemically. Similarly, the theory of evolution is more than just the statement that “evolution happened”: it is an extensively documented set of principles that explain how and why evolution happens.

For a theory to be considered scientific, it must be testable and make verifiable predictions. That is, we must be able to make observations about the real world that either support it or disprove it. Atomic theory was initially speculative, but gained more and more credibility as data from chemistry piled up supporting the existence of atoms. Although we couldn’t actually see atoms until scanning-probe microscopy was invented in 1981 (and under the microscope they do look like the little balls we envision), scientists were already convinced long before that atoms were real. A good theory makes predictions about what we should find if we look more closely at nature. And if those predictions are met, it gives us more confidence that the theory is true. Einstein’s general theory of relativity, proposed in 1916, predicted that light would be bent as it passed by a large celestial body. Sure enough, Arthur Eddington verified this prediction in 1919 by showing, during a solar eclipse, that light coming from distant stars was bent as it went by the sun, shifting the stars’ apparent positions. It was only when this prediction was verified that Einstein’s theory began to be widely accepted.

Because a [scientific] theory is accepted as “true” only when its assertions and predictions are tested over and over again, and confirmed repeatedly, there is no one moment when a scientific theory suddenly becomes a scientific fact.

A theory becomes a fact (or a “truth”) when so much evidence has accumulated in its favor—and there is no decisive evidence against it—that virtually all reasonable people will accept it. That does not mean that a “true” theory will never be falsified. All scientific truth is provisional, subject to modification in light of new evidence.

In Darwin’s day, the evidence for his theories [about evolution] was compelling but not completely decisive. We can say, then, that evolution was a theory (albeit a strongly supported one) when first proposed by Darwin, and since 1859 has graduated to “facthood” as more and more supporting evidence has piled up. Evolution is called a “theory” just like the theory of gravity, but it’s a theory that is also a fact.

—excerpts from Why Evolution is True, chapter 1, by Jerry Coyne, professor of Evolution at the University of Chicago

To read the next post in this series on Evolution click: here

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The Nested Arrangement of All Forms of Life is Strong Evidence Against Creationism

Nested arrangement of life: All species of plants and animals have a nested hierarchy; a hierarchy in which big groups of species whose members share a few traits are subdivided into small groups of species sharing more traits, and so on down to species, like black bears and grizzly bears, that share nearly all their traits.

The history of life forms a tree [like a family tree in genealogy books]. And it stands to reason that if the history of life forms a tree, with all species originating from a single trunk, then one can find a common origin of every pair of twigs (existing species) by tracing each twig back through its branches until they intersect at the branch they have in common. This node, as we’ve seen, is their common ancestor. And if life began with one species and split into millions of descendants species though a branching process, it follows that every pair of species shares a common ancestor sometime in the past.

Let’s examine one evolutionary [family] tree: vertebrates. Fish, amphibians, mammals, and reptiles all have a backbone—they are “vertebrates”—so they must have descended from a common ancestor that also had vertebrae. But within vertebrates, reptiles and mammals are united (and distinguished from fish and amphibians) by having an “amniotic egg”—the embryo is surrounded by a fluid-filled membrane called amnion. So reptiles and mammals must have had a more recent common ancestor that itself possessed such an egg. But this group also contains two subgroups, one with species that all have hair, are warm-blooded, and produce milk (mammals), and another with species that are cold-blooded, scaly, and produce watertight eggs (reptiles).

Swedish botanist, Carl Linnaeus

The nested arrangement of life was recognized long before Darwin. Starting with the Swedish botanist Carl Linnaeus in 1735, biologists began classifying animals and plants, discovering that they consistently fell into what was called a “natural” classification. Strikingly, different biologists came up with nearly identical groupings. This means that these groupings are not subjective artifacts of a human need to classify, but tell us something real and fundamental about nature But nobody knew what that something was until Darwin came along and showed that the nested arrangement of life is precisely what evolution predicts. Creatures with recent common ancestors share many traits, while those whose common ancestors lay in the distant past are more dissimilar. The “natural” classification is itself strong evidence for evolution.

How does this disprove Creationism? Answer: Because we don’t see a nested arrangement if we’re trying to arrange objects that haven’t arisen by an evolutionary process of splitting and descent. If Creationism were true we should not see this hierarchical pattern. If Creationism were true, sorting and classifying animals and plants, would be like sorting and classifying matchbooks. Each person sorting and classifying matchbooks uses his or her own sorting system. Some would use size, others would use color, etc.. There is no standard sorting system for classifying matchbooks that all collectors would agree on. This is because rather than evolving, so that each matchbook gives rise to another that is only slightly different, each design was created from scratch by human whim.

Matchbooks resemble the kinds of creatures expected under a creation explanation of life. In such a system, organisms would not have common ancestry, but would simply result from an instantaneous creation of forms designed de novo to fit their environments. Under this scenario, we wouldn’t expect to see species falling into a nested hierarchy of forms that is recognized by all biologists.

—excerpts from Why Evolution is True, chapter 1, by Jerry Coyne, professor of Evolution, University of Chicago

To read the next post in this series on Evolution click: here

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Primer for Fundamentalist Christians: Darwinian Evolution Made Simple

The modern theory of evolution is easy to grasp. It can be summarized in a single (albeit slightly long) sentence: Life on earth evolved gradually beginning with one primitive species—perhaps a self-replicating molecule—that lived more than 3.5 billion years ago; it branched out over time, throwing off many new and diverse species; and the mechanism for most (but not all) of evolutionary change is natural selection.

When you break that sentence down, you find that it really consists of six components: evolution, gradualism, speciation, common ancestry, natural selection, and nonselective mechanisms for evolutionary change.

Evolution: a species undergoes genetic change over time. Over many generations, a species can evolve into something quite different, and these differences are based on changes in DNA, which originate as mutations. Although all species evolve, they don’t do so at the same rate. [The rate of change] depends on the evolutionary pressures they experience.

Gradualism: it takes many generations to produce a substantial evolutionary change , such as the evolution of birds from reptiles. The evolution of new features, like the teeth and jaws that distinguish mammals from reptiles, does not occur in just one or a few generations, but usually over hundreds or thousands—or millions—of generations. Some change can occur very quickly. Populations of microbes have very short generations, some as brief as twenty minutes. This means that these species can undergo a lot of evolution in a short time, accounting for the depressingly rapid rise of drug resistance in disease-causing bacteria and viruses. But when talking about really big change, we’re usually referring to change that requires many thousands of years.

Speciation (splitting): the evolution of different groups within a species to the point where they can no longer interbreed. The ancestor species splits into two separate species; individuals of the first new species are incapable of breeding with individuals of the second new species. For example, two populations of a single reptilian species, probably living in different places, begin to evolve slight differences from each other. Over a long time, these differences gradually grew larger. Eventually the two populations would have evolved sufficient genetic differences that members of the different populations could not interbreed. (There are many ways this can happen: members of different animal species may no longer find each other attractive as mates, or if they do mate with each other, offspring could be sterile.)

The birth of the ancestor of all birds wouldn’t have looked so dramatic at the time. We wouldn’t have seen the appearance of flying creatures from reptiles. but merely two slightly different populations of the same [ancestor species], probably no more different than members of diverse human populations are today. But species don’t have to split. Whether they do depends on whether circumstances allow populations to evolve enough differences that they are no longer able to interbreed. The vast majority of species—more than 99% of them—go extinct without leaving any descendants.

Although speciation is slow, it happens sufficiently enough, over such long periods of history, that it can easily explain the stunning diversity of living plants and animals on earth.

Common Ancestry: we can always look back in time, using either DNA sequences or fossils, and find descendants joining at their ancestors. Creatures with recent common ancestors share many traits, while those whose ancestors lay in the distant past are more dissimilar. This phenomenon, called the nested arrangement of life, had been noticed long before Darwin. This nested arrangement of life is itself strong evidence for evolution. DNA sequencing has confirmed pre-DNA “family trees” of evolutionary relationships among species.

Natural Selection: If individuals within a species differ genetically from one another, and some of those differences affect an individual’s ability to survive and reproduce in its environment, then in the next generation the “good” genes that lead to higher survival and reproduction will have relatively more copies than the “not so good” genes. Over time, the population will gradually become more and more suited to its environment as helpful mutations arise and spread through the population, while deleterious ones are weeded out. Ultimately, this process produces organisms that are well adapted to their habitats and way of life.

Example: The wooly mammoth whose remains have been found in North Eurasia and North America. These creatures probably descended from mammoth ancestors that had little hair—like the modern elephant. Mutations led to some individual mammoths being more hairy than others. When the climate became cold or the species spread to more northern regions, the hirsute [hairy] individuals were better able to tolerate their frigid surroundings and left more offspring than their balder counterparts. This enriched the population in genes for hairiness. In the next generation, the average mammoth will be slightly hairier. Let this process continue over some thousands of generations, and your smooth mammoth gets replaced by a shaggy one. The process is remarkably simple. And since many traits can affect an individual’s adaptation to its environment (its “fitness”), natural selection can, over eons, sculpt an animal or plant into something that looks designed.

Processes other than natural selection can cause evolutionary change: The most important is the simple random changes in the proportion of genes caused by the fact that different families have different numbers of offspring. This leads to evolutionary change that, being random, has nothing to do with adaptation. (see genetic drift)

— Excerpts from Why Evolution is True, chapter 1, by Jerry Coyne, professor of Evolution, University of Chicago

To see the next post in this series on Darwinian Evolution, click: here

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Intelligent Design Makes So Much Sense

If anything is true about nature, it is that plants and animals seem intricately and almost perfectly designed for living their lives. Squids and flatfish change color and pattern to blend in with the their surroundings, becoming invisible to predator and prey. Bats have radar to home in on insects at night. Hummingbirds, which can hover in place and change position in an instant, are far more agile than any human helicopter, and have long tongues to sip nectar lying deep within flowers. And the flowers they visit also appear designed—to use hummingbirds as sex aids. For while the hummingbird is busy sipping nectar, the flower attaches pollen to its bill, enabling it to fertilize the next flower that the bird visits. Nature resembles a well-oiled machine, with every species an intricate cog or gear. What does all this seem to imply? A master mechanic, of course.

—Jerry Coyne, professor of Ecology and Evolution at the University of Chicago in his book, Why Evolution is True

Gary: When I was a fundamentalist Christian it seemed so obvious to me: Life is just too complex to have happened by chance. The theory of evolution seemed sooo ridiculously silly! Preachers in my denomination often compared evolution with placing all the separate pieces of a pocket watch into a shoe box, putting the lid on, then shaking the box and expecting that after shaking the box a few times a fully operational pocket watch is going to appear in the box. Common sense tells you that is never going to happen! Why can’t those snobby university science professors teaching evolution see that? The answer, I was told by my pastors, was this: Scientists and university science professors know evolution is false, but since they are atheists and hate God so deeply, they have invented evolution as a means of destroying Christianity and belief in God.

Common sense is very important in our lives. It can save your life! But is it always correct? I suggest, no. It is not. Science should always trump common sense and here is a simple example why: For thousands of years humans believed that the sun revolves around the earth simply because that is what common sense tell us. If you sit in front of your north or south facing house, you can watch the sun rise in the east, slowly cross the sky during the day, and then disappear below the horizon in the west. And this same process will happen day after day after day. It took a scientist using the scientific method to show us that in regards to the relationship between the earth and the sun, our common sense fails us. The sun does not revolve around the earth. The earth revolves around the sun.

Trust science, folks, not common sense.

I will be reviewing Jerry Coyne’s Why Evolution is True over the next few posts. To see next post in the series, click: here

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Origin of the Resurrection Story: Jesus Had a Doppelganger

Which man is Keanu Reeves and which man is his doppelganger?

Isn’t this scenario the likely origin of the stories that Jesus appeared to groups of his followers after his death:

Groups of Jesus’ followers and/or family saw Jesus’ doppelganger (a case of mistaken identity) in a crowd or on a distant hill a few weeks or months after his execution and believed for a brief time that they had seen him alive. But once he “disappeared” (around a corner, into the crowd, or over a hill) they then assumed something miraculous (supernatural) had happened: he had been raised back to life by an act of God to fulfill his destiny as Messiah!

When days, weeks, or months passed and Jesus hadn’t shown up to establish the New Kingdom to rule Israel as the Anointed One (messiah), this belief morphed into the belief that he had been “resurrected” by an act of God and taken to heaven where he was preparing for his return.

Cognitive dissonance plays amazing tricks on the mind, in particular the minds of superstitious religious zealots in newly formed sects and cults.

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The Most Likely Origin of Jesus Appearances to Groups Stories: Mistaken Identity

Do dead people suddenly pop out of thin air to appear to human beings? Answer: Only in Sci-Fi flicks, ancient mythology, and the Bible. Here is what I believe to be the probable origin of these fantastical supernatural claims:

The multiple alleged sightings of a “resurrected Jesus” suddenly appearing (out of thin air) to groups of people (found in the four Gospels and the Book of Acts) could be explained by cases of mistaken identity. The disciples and family of Jesus saw someone in a crowd or in the distance who looked like Jesus; they were unable to catch up with this person before he “disappeared”; the family/disciples later interpreted this very odd, unexpected, emotionally jarring event as an “appearance” of Jesus.

The manner of appearance could have been interpreted in several ways:

–an appearance of Jesus’ pre-death human body which had been “raised” back to life by a miracle of a god, specifically, the Hebrew god, Yahweh. In other words, Jesus was alive again in the exact same human body he had before his execution. The same human body that needed to eat and use the toilet, just like every other human body on the planet.

— an appearance of a heavenly (supernatural) body that had the outline/form of a human body but possessed other characteristics and properties which made it discernably not human.

— an appearance of a reanimated/transposed dead human body (the exact same body as before Jesus’ death) infused with supernatural powers and properties (the Trinitarian concept).

–or another supernatural alternative.

Ok, Christian apologists: Why is this natural explanation not the probable explanation for the first century claims that the resurrected Jesus appeared to groups of people?

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Reader Challenge: Find a Dead Person Sighting that Matches the Jesus Story

Is that you, Jesus?

The first reader of this blog who can meet the following challenge made to me by a Christian reader will win a copy of John Loftus landmark book, The Case Against Miracles:

Challenge from FT Bond, aka Polycarp’s Scribe, aka Holy Moly, a Christian reader of this blog: Find me a real-life, documented example of the kind of thing you’re proposing: [A mistaken identity sighting of Jesus after his death in which the family and/or friends of Jesus see someone who looks like Jesus but isn’t, maybe in a crowd or in the distance, who then “disappears” from sight, leading Jesus’ family and friends to believe from then on for the rest of their lives that he had miraculously risen from the dead, a delusion which ultimately evolved into the resurrection claim.]

Scenario: Bob’s wife dies. X-months later, Bob “sees” his wife across a busy street, but she’s lost in the crowd. And from then on, Bob claimed his wife was alive. Find me one example of that in real life. Support your theory. Otherwise, it’s hot air.

Gary: Find the exact scenario FT Bond is requesting and you win the book!

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Alleged Sightings of a Dead Jesus is Not Unusual. Grieving Friends and Family Often “See” Their Dead Loved One

Should we be at all surprised that the friends and family of Jesus thought they had seen him alive again? No. It is a common occurrence among grieving family members and friends, in particular when the death is sudden and unexpected. Here is one story:

Source: We’re transfixed, watching a stranger pump gas. My mom, dad, and I are frozen on high, animalistic alert, as we watch the young man at the neighboring gas pump. After moments that feel like years, he turns, and his face is all wrong. A five-o’clock shadow peppers his face, his cheeks are too ruddy, his eyes too far apart.

He is not my dead brother. Not my parents’ lost son.

When my brother died of a combination of drugs and alcohol three months earlier, it seemed impossible. This happens to other families, I’d thought irrationally. Though I’d suspected he’d been toying with dangerous drugs, the shock of him actually dying was acute and metallic.

When possible, family members may view a loved one’s body following a death. It’s a ritual, one last chance to take in the face, the hands, the neck of someone we loved. To see the skin paled and cool, the indefinable yet palpable absence of life helps us bridge the space between our lives before the loss and the new, wrenching after.

But this wasn’t possible. My brother’s body had lain in his apartment in another state for four days before being discovered. Those four days had, according to the autopsy report, turned his blue eyes brown, mottled his skin, made him bloat and blacken. Seeing what remained of him would’ve added to our trauma, decorating the dark visions in our minds with more clarity, more terrible detail than we could conjure on our own.

It’s hard to believe what we can’t see. When I was pregnant, I knew abstractly that there was a baby growing inside of me. That cells were multiplying, organs and flesh being knit together, a design both miraculous and native being followed. But until the moment I saw each of my children, until I looked into their slate-gray eyes, until I felt their warm squirming legs and startled arms, some part of me didn’t really believe they were real.

In the same way, without seeing my brother’s body, our minds struggled to believe he was truly dead.

And so we searched.

We’d spot someone in the grocery store with short sandy hair and a gray hooded sweatshirt, and we’d follow him until he turned to browse the tomato sauce section, only to see the nose and chin were all wrong. Of course it’s not Will. Will is dead, I’d think to myself, wondering if grief could actually drive a person insane. The answer was probably yes.

A young man, clad in beige Carhartt coveralls, haunted the street where my dad worked. Like my brother, the boy was heavyset with thick, dark blond hair, and a similar shuffling gait. I saw him today, my dad would say grimly after work. We’d all seen him; from behind, he looked so much like my brother that I’d think, oh, there’s Will! before my brain reminded me that Will was gone.

There were moments when the reality of Will’s death seeped in. Like when the hulking van pulled up in my parents’ driveway, lugging my brother’s belongings; big cardboard boxes brimming with CDs and journals, a toolbox that smelled of campfire, a small stack of letters from friends and family. As we sorted through his things, a wave of finality washed over me. He’s not coming back. He’s not just on a vacation. He’s dead.

Gary: Isn’t it possible that the alleged appearances of Jesus were based on similar sightings as occurred with this family? Someone in the distance, in a crowd, turns and looks your way. He waves and smiles. It is your dead friend! But it isn’t. It is someone who looks like your dead friend. And he wasn’t waving and smiling at you, but at someone else near you. You have just experienced a “false dead person sighting”. I believe that such false sightings most likely accounted for some of the group sightings of Jesus.

Brain dead bodies never come back to life, folks. Accept reality.

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Fifteen Eyewitnesses See Mary, Joseph, St. John, and Angels. Should We Believe Them?

Altar sculpture of what approximately 15 eyewitnesses allege they saw in Knock, Ireland, August 21, 1879. Why don’t Protestants believe them?

Evangelical and other Protestant Christian apologists insist that we accept the eyewitness testimony of the persons listed in the Early Creed found in First Corinthians 15 because: “Groups of people cannot have the same hallucination. If multiple eyewitnesses describe seeing Jesus, at the same time and place, the story must be true.”

Really? Then why don’t evangelical and other Protestant Christians accept as historical fact this appearance claim: a group of people, at the same time and place, claimed to see the Virgin Mary, Joseph, the apostle John, and a host of angels?? Notice they did not claim to just see bright lights or shadows.

Source: On August 21, 1879, a group of 15 men, women, and children, ranging in age from 5 to 75, reported seeing an apparition behind their church, against the back wall, of an altar with a lamb on it (understood to represent Jesus), surrounded by a multitude of angels. Off to the side in prayer stood Mary, Joseph, and St. John (with St. John dressed as a bishop). Because Mary was among those seen, the apparition is classified as Marian, although the simultaneous appearance of Jesus, Mary, Joseph, John, and numerous angels makes it unique among this category. A further distinctive characteristic is that this apparition was silent: no verbal messages were given. The apparition lasted for an hour and a half.^[23]

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Husband And Wife Abducted By Aliens. Should We Believe These Eyewitnesses?

Christian apologists insist that the resurrection of Jesus must be an historical fact because groups of eyewitnesses claimed to have seen his walking, talking resurrected body. “Either the eyewitnesses were hallucinating, lying, or telling the truth. There are no other options. Medical experts assure us that two people cannot experience the same hallucination. And it makes no sense that they were lying, because many of them died for this belief. People do not die for a lie. So the only option that remains is: the eyewitnesses were telling the truth!”

But is it true that there are only three possible explanations for the alleged sightings of a resurrected, walking, talking corpse in circa 33 CE: Hallucination, lie, or truth? Isn’t it possible for groups of people to experience a very odd event involving an illusion (bright lights, clouds, shadows, etc.) and after some reflection and discussion, come away believing that they had experienced an other worldly event, agreeing on the important (but imagined) details? Yes! Here is one such story:

Source: In 1961, Betty and Barney Hill…[were] traveling through New Hampshire’s White Mountain range one evening when Barney spotted a low-flying disc-shaped object about 100 feet above ground. He left his wife in the car and used his binoculars to peek in, later describing looming, non-human figures cloaked in black. Then — for two inexplicable hours — everything went black. Betty Hill’s new blue dress was torn from the top of the zipper down to the hem and sprinkled with a mysterious pink powder. Barney Hill’s shoes were scraped, his binoculars rubbing his neck raw with friction. Both their wristwatches were frozen at the same time; the car was marked with shiny spots that made any compass placed on top go haywire. Betty and Barney Hill had been abducted by aliens.

…Expectedly, science isn’t sold on the burgeoning movement to accept the experiences of alien abductees. In 2008, Columbia University psychoanalyst David V. Forrest wrote a paper based off the Hill’s case and suggested the couple was dealing with accidental awareness, which is when a person is in a fuzzy state of consciousness while under anesthesia. As Scientific American reported in 2014:

While in a hypnotic trance, Barney Hill told his psychiatrist, “I don’t want to be operated on.” He described a spacecraft lit by blue fluorescent light, which didn’t cast any shadows, as in a surgical suite. The aliens had oddly shaped heads with large craniums, and indistinct lips and nostrils; they were all foreheads and eyes. Though he was terrified, he felt sluggish. He was struck by the all-business, professional bedside manner of the alien “doctors,” and impressed by their determination to do whatever it was they meant to do.

Some psychologists have suggested that alien abductees are potentially recovering memories in the deep recesses of their brains from a previous traumatic event. For Barney Hill, that might have been a childhood tonsillectomy. And in that respect, the Hills experience might actually be reflective of the continuing mystery of how exactly our brains store memories. There’s the idea that there is “everyday” memory — you remember what you ate for breakfast (if at all) this morning. There’s “routine” memory — the way to go to work, dialing phone numbers. Then there’s “trauma” memory, which is connected with PTSD. Anesthesia can induce these memories, as well as intense emotional states that invoke deja vu. They aren’t necessarily logical but can powerfully reproduce a sensation that was suppressed — pain, panic, general freaking out.

Gary: The early Christians had experienced a very traumatic event: the sudden, unexpected death of their leader and friend and the fear that they might be next. Based on what we know from modern cases of PTSD, such as that of the Hills above, horrific experiences can trigger hallucinations, delusions, and/or the misinterpretation of odd events in one’s environment (illusions)? Doesn’t probability suggest that this is exactly what happened in the case of the Resurrection of Jesus Story?

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