Category Archives: Evolution

Evolution

How Is Evolution Defined? Part 2

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Post Author: Bill Pratt

In part 1, we looked at 6 definitions of evolution and explained how different Christian creationist positions deal with them.  If you recall, definition 6 was the most controversial:

6. “Blind watchmaker” thesis: the idea that all organisms have descended from common ancestors solely through unguided, unintelligent, purposeless, material processes such as natural selection acting on random variations or mutations; that the mechanisms of natural selection, random variation and mutation, and perhaps other similarly naturalistic mechanisms, are completely sufficient to account for the appearance of design in living organisms.

Jay Richards has several interesting things to say about definition 6 that are worth repeating:

Of all the senses of evolution, this one seems to fit with theism like oil with water. According to the blind watchmaker thesis, all the apparent design in life is just that—apparent. It’s really the result of natural selection working on random genetic mutations. (Darwin proposed “variation.” Neo-Darwinism attributes new variations to genetic mutations.)

The word “random” in the blind watchmaker thesis carries a lot of metaphysical baggage. In Neo-Darwinian theory, random doesn’t mean uncaused; it means that the changes aren’t directed—they don’t happen for any purpose. Moreover, they aren’t predictable, like gravity, and don’t occur for the benefit of individual organisms, species, or eco-systems, even if, under the guidance of natural  selection, an occasional mutation might enhance a species odds of survival.

The blind watchmaker thesis is more or less the same as Neo-Darwinism as its leading advocates understand it. It is usually wedded to some materialistic origin of life scenario, which isn’t about biological evolution per se. This so-called chemical evolution is often combined with biological evolution as two parts of a single narrative.

Unfortunately, the blind watchmaker thesis isn’t an eccentric definition of the word evolution. It’s textbook orthodoxy. For instance, Harvard paleontologist George Gaylord Simpson explained evolution by saying, “Man is the result of a purposeless and natural process that did not have him in mind.” Darwin himself understood his theory this way: “There seems to be no more design,” he wrote, “in the variability of organic beings, and in the action of natural selection, than in the course which the winds blow.”

And here’s how the late Darwinist Ernst Mayr put it: “The real core of Darwinism, however, is the theory of natural selection. This theory is so important for the Darwinian because it permits the explanation of adaptation, the ‘design’ of the natural theologian, by natural means, instead of by divine intervention.” Notice that Mayr says, “instead of.”

These are representative quotes from the literature. From the time of Darwin to the present, Darwinists have always contrasted their idea with the claim that biological forms are designed or created. That’s the whole point of the theory.

Theists claim that the world, including the biological world, exists for a purpose; that it is, in some sense, designed. The blind watchmaker thesis denies this. So anyone wanting to reconcile strict Darwinian evolution with theism has a Grade A dilemma on his hands.

Evolution

How Is Evolution Defined? Part 1

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Post Author: Bill Pratt

One of the first things I was taught in my seminary classes was to carefully define terms and concepts before launching into a debate over them.  So many times, when I see two people arguing about a topic, they are using different definitions for the same words.  It’s impossible to have a productive discussion with someone when you don’t agree on how to define terms.

Recently I read a great article in the Christian Research Journal (Vol. 35 / No. 1 / 2012), written by Jay Richards, on the topic of evolution and its varying definitions.  The article is entitled “Thinking Clearly about God and Evolution.”  I thought I would excerpt some portions of the article because I think it will be helpful to all of us when we discuss this controversial subject.

Richards writes:

It’s a lot easier to define theism than to define evolution. It’s been called the ultimate weasel word. In an illuminating article called “The Meanings of Evolution,” Stephen Meyer and Michael Keas attempt to catch the weasel by distinguishing six different ways in which “evolution” is commonly used:

1. Change over time; history of nature; any sequence of events in nature.

2. Changes in the frequencies of alleles in the gene pool of a population.

3. Limited common descent: the idea that particular groups of organisms have descended from a common ancestor.

4. The mechanisms responsible for the change required to produce limited descent with modification, chiefly natural selection acting on random variations or mutations.

5. Universal common descent: the idea that all organisms have descended from a single common ancestor.

6. “Blind watchmaker” thesis: the idea that all organisms have descended from common ancestors solely through unguided, unintelligent, purposeless, material processes such as natural selection acting on random variations or mutations; that the mechanisms of natural selection, random variation and mutation, and perhaps other similarly naturalistic mechanisms, are completely sufficient to account for the appearance of design in living organisms.

As Christians, what are we to make of these 6 different definitions of evolution?  Definitions 1-4 are almost universally accepted by young earth, old earth, and theistic evolutionists.  They all agree that plant and animal populations have changed over time, that there is limited common descent, and that natural selection acting on random mutation does affect plant and animal populations.

Definition number 5 is where young earth and old earth creationists get off the boat.  These folks believe that God specially created different kinds of plants and animals at specific moments in earth’s history.  Old earth creationists stretch out those creative acts over some 3.5-4 billion years, whereas young earth creationists compact those creative acts into a 6-day period.  In either case, it would be impossible for  universal common descent to be true.  Finally, theistic evolutionists would have no problem with definition 5.

Definition 6 is where even theistic evolutionists disembark.  Why?  Because they do not accept that evolution is “unguided, unintelligent, [and] purposeless.”  God is behind evolution and He planned it out and executed on the plan through the initial conditions and physical laws that he put in place.

In part 2, I will excerpt some further insightful comments from Richards on definition 6, which is by far the most controversial definition of evolution.

Evolution

What Can We Know About Prehistoric Man? Part 2

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Post Author: Bill Pratt

In part 1 , we started looking at G. K. Chesterton’s commentary on the zeal of paleontologists of his day.  Chesterton noted that there is a definite and often ignored difference between the science of paleontology and empirical sciences such as aerodynamics.  In part 2, we hear more from Chesterton on the extrapolations he saw in his day:

For instance, I have pointed out the difficulty of keeping a monkey and watching it evolve into a man. Experimental evidence of such an evolution being impossible, the professor is not content to say (as most of us would be ready to say) that such an evolution is likely enough anyhow.

He produces his little bone, or little collection of bones, and deduces the most marvellous things from it. He found in Java a piece of a skull, seeming by its contour to be smaller than the human. Somewhere near it he found an upright thigh-bone and in the same scattered fashion some teeth that were not human. If they all form part of one creature, which is doubtful, our conception of the creature would be almost equally doubtful.

But the effect on popular science was to produce a complete and even complex figure, finished down to the last details of hair and habits. He was given a name as if he were an ordinary historical character. People talked of Pithecanthropus as of Pitt or Fox or Napoleon. Popular histories published portraits of him like the portraits of Charles the First and George the Fourth. A detailed drawing was reproduced, carefully shaded, to show that the very hairs of his head were all numbered.

No uninformed person looking at its carefully lined face and wistful eyes would imagine for a moment that this was the portrait of a thigh-bone; or of a few teeth and a fragment of a cranium. In the same way people talked about him as if he were an individual whose influence and character were familiar to us all.

The historical sciences, as we have pointed out many times on this blog, operate very differently than the empirical sciences.  We are far more certain about the laws of aerodynamics than the activities of Homo erectus.  One we can test with live experimentation, and the other we cannot.

Let me be clear that I am not saying that historical sciences give us no knowledge about the past.  Paleontology, as an example, can tell us many interesting things about prehistoric life.  What I and Chesterton are saying is that there are much larger error bars on what paleontology tells us than what the science of aerodynamics tells us.  The interpretation of the data from paleontology is far less sure than the data from aerodynamics.  It behooves the scientific community to make these differences clear.

Evolution

What Can We Know About Prehistoric Man? Part 1

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Post Author: Bill Pratt

It never ceases to amaze me that a certain breed of skeptic will believe everything presented in an hour-long History Channel program about an alleged prehistoric ancestor of Homo sapiens – all of it based on a couple fossils – and yet believe nothing in the voluminous written historical records contained in the Bible.

I have seen hours of TV programming that presents prehistoric man doing all sorts of things which are virtually impossible to derive with any certainty from fossils.  Entire animation departments render complete anatomical drawings of man’s ancestors with only partial skulls and teeth to go by.  Where does all the skepticism go when these far-fetched fairy tales are aired?

Although G. K. Chesterton is not a paleontologist, I appreciated his description of this same issue from the early twentieth century.  He was seeing the same kinds of wild extrapolations that I am seeing today.  Here are his thoughts on this issue, from the book The Everlasting Man:

Science is weak about these prehistoric things in a way that has hardly been noticed. The science whose modern marvels we all admire succeeds by incessantly adding to its data. In all practical inventions, in most natural discoveries, it can always increase evidence by experiment. But it cannot experiment in making men; or even in watching to see what the first men make.

An inventor can advance step by step in the construction of an aeroplane, even if he is only experimenting with sticks and scraps of metal in his own back-yard. But he cannot watch the Missing Link evolving in his own back-yard. If he has made a mistake in his calculations, the aeroplane will correct it by crashing to the ground. But if he has made a mistake about the arboreal habitat of his ancestor, he cannot see his arboreal ancestor falling off the tree.

He cannot keep a cave-man like a cat in the back-yard and watch him to see whether he does really practice cannibalism or carry off his mate on the principles of marriage by capture. He cannot keep a tribe of primitive men like a pack of hounds and notice how far they are influenced by the herd instinct. If he sees a particular bird behave in a particular way, he can get other birds and see if they behave in that way; but if he finds a skull, or the scrap of a skull, in the hollow of a hill, he cannot multiply it into a vision of the valley of dry bones.

In dealing with a past that has almost entirely perished, he can only go by evidence and not by experiment. And there is hardly enough evidence to be even evidential. Thus while most science moves in a sort of curve, being constantly corrected by new evidence, this science flies off into space in a straight line uncorrected by anything.

But the habit of forming conclusions, as they can really be formed in more fruitful fields, is so fixed in the scientific mind that it cannot resist talking like this. It talks about the idea suggested by one scrap of bone as if it were something like the aeroplane which is constructed at last out of whole scrapheaps of scraps of metal. The trouble with the professor of the prehistoric is that he cannot scrap his scrap. The marvellous and triumphant aeroplane is made out of a hundred mistakes. The student of origins can only make one mistake and stick to it.

More from Chesterton in part 2, and some closing remarks about the whole issue of historical sciences.

Atheism, Evolution, Philosophy

How Can We Trust Science in Richard Dawkins’ Middle World?

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Post Author: Bill Pratt

In the last chapter of Richard Dawkins’ The God Delusion, he introduces the metaphor of Middle World.  The idea of Middle World is that the human sensory organs have only evolved in order to help humans survive in a world of medium-sized objects moving at relatively slow speeds (compared to the speed of light).  Dawkins observes that “our brains are themselves evolved organs: on-board computers, evolved to help us survive in a world — I shall use the name Middle World — where the objects that mattered to our survival were neither very large nor very small; a world where things either stood still or moved slowly compared with the speed of light.”

We are ill-equipped to deal with the vast distances to other galaxies or the sub-atomic world.  In fact, the way we perceive objects is misleading.

Science has taught us, against all evolved intuition, that apparently solid things like crystals and rocks are really composed almost entirely of empty space. The familiar illustration represents the nucleus of an atom as a fly in the middle of a sports stadium. The next atom is right outside the stadium. The hardest, solidest, densest rock, then, is ‘really’ almost entirely empty space, broken only by tiny particles so far apart that they shouldn’t count.

Our senses, then, do not give us an accurate picture of reality.  According to Dawkins, “Our brains are not equipped to imagine what it would be like to be a neutrino passing through a wall, in the vast interstices of which that wall ‘really’ consists. Nor can our understanding cope with what happens when things move at close to the speed of light.”

If Dawkins had stopped at this point, all would be well.  Nobody would argue that we are ill-equipped to see sub-atomic particles, that our sensory organs are limited.  Dawkins doesn’t stop here, though, because he wants to hammer home just how limited we are.  What we really perceive as reality, argues Dawkins, is only a mental model.

What we see of the real world is not the unvarnished real world but a model of the real world, regulated and adjusted by sense data—a model that is constructed so that it is useful for dealing with the real world. The nature of that model depends on the kind of animal we are.

Once the mental model concept is introduced, it is my contention that Dawkins ends up eviscerating our very ability to know anything about reality.  He is arguing that we really don’t know what reality is like because we only have the mental models that our species has evolved, and those mental models have proven to be incomplete and inaccurate time and again. In fact, humans are constantly surprised by just how wrong our models are.

But wait!  There is a savior that will rescue us from our ignorance.  Dawkins elates, “Science flings open the narrow window [of Middle World] through which we are accustomed to viewing the spectrum of possibilities. We are liberated by calculation and reason to visit regions of possibility that had once seemed out of bounds or inhabited by dragons.”

How can this be, though?  On the atheist worldview, do not science, calculation, and reason all depend completely on the severely limited human brain which has consistently given us inaccurate mental models of reality?  How is it that the very organ which has constantly misled us about reality will be our savior?  Isn’t this the classic case of the blind leading the blind?

Dawkins, like most atheists, just assumes that human reason magically works, that science marches inexorably to the Truth. But on the atheist view, reason and the ability to do science, all comes from the evolved human brain, an organ that, according to Dawkins, can’t be trusted to see the world as it really is, an organ that fools us.  There is no soul, no rational God that guarantees that our reason actually works.  So, I ask, how can we trust science in Richard Dawkins’ Middle World?

Creation, Essential Beliefs, Evolution

What Is the One True Christian View on Evolution?

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Post Author: Bill Pratt

Trick question!  There isn’t one, despite what some people will tell you.  You see, the issue of exactly how God brought forth life on earth is just not something that is part of the essential teachings of Christianity.  What are the essential teachings of Christianity?  Those doctrines that were elucidated by the creeds and councils of the first five centuries of the church.  The question of how life formed was never a central part of these creeds and councils, so we can safely assume that the apostolic tradition was not particularly concerned with it.

Today, there are a great variety of views on the formation of life within orthodox Christianity.  Tim Keller gives a nice survey of the wide spectrum of views:

Some Christians in the highly publicized Creation Science movement . . . insist that Genesis 1 teaches that God created all life-forms in a period of six twenty-four-hour days just several thousand years ago.  At the other end of the spectrum are Christians who take the independence model and simply say that God was the primary cause in beginning the world and after that natural causes took over.  Other thinkers occupy the central positions.  Some hold that God created life and then guided natural selection to develop all complex life-forms from simpler ones.  In this view, God acts as a top-down cause without violating the process of evolution.  Others, believing there are gaps in the fossil record and claiming that species seem to “appear” rather than develop from simpler forms, believe that God performed large-scale creative acts at different points over longer periods of time.

I tend to lean toward the last view Keller mentions, but I am not completely certain and stand ready to hear differing points of view.

Why am I bringing this up?  Because there are too many non-Christians who are letting the question of evolution get in the way of their turning to Christ.  My plea is simple.  Focus on the central teachings of Christianity first.  Take a good look at Jesus Christ – who he is and what he accomplished.  After getting those things straight, you may want to investigate the origins of life to try and figure out how God created all the organisms we see around us.  Please put first things first and don’t let the debates over evolution divert you from the most important decision you’ll ever make.

Evolution, Intelligent Design

Top Ten Intelligent Design and Evolution Science News Stories of 2010

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Post Author: Bill Pratt

This post is a few months belated, but better late than never.  Every year, Access Research Network does a phenomenal job collecting science news that bears on the intelligent design and evolution debate.  For 2010, they have again assembled a great list.  If you are at all interested in this debate, please go read the article where they have compiled the stories.

Evolution, Intelligent Design

Which Part of Evolution Are We Talking About?

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Post Author: Bill Pratt

I have followed the intelligent design (ID) movement for several years now and there is an error that I’ve seen opponents of ID make over and over.

The error is confusing the idea of common descent with the idea of random mutation and natural selection.

Common descent refers to the idea that all animal life is related, that if we trace back each living animal’s ancestry, we would find common ancestors.  If every animal could trace back its family history through ancestor.com, we would all find that we came from the same great, great, great (insert great thousands or millions of times) grandparents.  Some of us are closer relatives than others but we are all related if we go back far enough in history.  The idea of common descent can be supported by evidence from the fossil record and by comparing the DNA sequences of different kinds of animals.

The idea of random mutation and natural selection attempts to explain how animals have changed over time into all the diverse species we see today and in the fossil record.  Every time an animal reproduces, there is a chance for a genetic mutation occurring in the process.  If the mutation that the offspring inherits is helpful to its survival until it, too, can reproduce, well then the mutation is passed on to the next generation, and so on.

In this way, the genetic code is altered, and if enough of these mutations occur over time, you get a new species of animal.  The empirical evidence for this mechanism only demonstrates very small, and in many ways, trivial instances of change (e.g., finch beaks, peppered moths, antibiotic resistance, fruit fly mutations).  There is no empirical evidence of large scale evolution due to random mutation and natural selection (see Michael Behe’s The Edge of Evolution and my recent post on this topic).

Which idea does ID challenge?  Common descent or the mechanism of random mutation and natural selection?

ID theory almost exclusively addresses the mechanism of random mutation and natural selection, not common descent.  ID challenges the idea that complex, specified biological systems can develop through random mutation and natural selection.  Regardless of this fact, time and again, opponents of ID throw evidence of common descent at ID proponents, only revealing their ignorance of ID.  Just recently on this blog, as I was discussing the lack of empirical evidence for random mutation and natural selection, I was treated to commenters’ arguments again for common descent; the error seems pervasive.

It is time that we understand the difference between these two ideas.  I would love to hear good arguments against ID theory, but first ID opponents actually need to do some reading and try to understand what they are opposing.  Almost 9 times out 10, when I read opponents of ID, they badly  misunderstand the theory.  If anyone can point me to actual ID opponents who understand ID, I would much appreciate it.

Evolution

Can Fossils Indicate Ancestry?

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Post Author: Bill Pratt

In most cases, fossils cannot give us ancestry, according to paleontologist Donald Prothero.  This statement, coming from Prothero, shocked me when I first read it, because it seems like fossil news headlines always make claims about ancestry, but here is Prothero, a staunch supporter of evolution, disagreeing.

Let me explain, lest I be accused of quote mining.  In his book Evolution, Prothero dedicates an entire chapter to explaining how scientists classify plant and animal life.  According to Prothero, the dominant method used today is cladistics, where the relationships among animals and plants are determined by the comparison of shared derived characters.  This theory has only taken hold in the last few decades, replacing older systems of classification.

A cladogram (cladistic diagram) comparing an assortment of vertebrates (e.g., lamprey, shark, frog, cow, monkey, human) might look at shared derived characters such as jaws, vertebrae, lungs, four legs, hair, mammary glands, opposable thumb, and stereovision.  Cladograms are powerful tools for classifying life because they are using directly observable evidence taken from living animals and from fossils.  But do cladograms indicate fossil ancestry?  Only minimally.  Here is Prothero:

Some aspects of cladistic theory have proven more difficult for many scientists to accept.  For example, a cladogram is simply a branching diagram of relationships between three or more taxa.  It does not specify whether one taxon is ancestral to another; it only shows the topology of their relationships as established by shared derived characters.  In its simplicity and lack of additional assumptions, it is beautifully testable and falsifiable.

Prothero explains that cladistics frustrate some evolutionists who want to say more about ancestry from the cladograms, but Prothero urges caution:

The biggest sticking point is the concept of ancestry.  We tend to use the term ancestor to describe certain fossils, but we must be careful when making that statement.  If we want to be rigorous and stick to testable hypotheses, it is hard to support the statement that ‘this particular fossil is the ancestor of all later fossils of its group’ because we usually can’t test that hypothesis.  Because the fossil record is so incomplete, it is highly unlikely that any particular fossil in our collections is the remains of the actual ancestor of another taxon.

What is refreshing about these statements from Prothero is that we are seeing actual scientific restraint when it comes to the analysis of fossils.  Unfortunately this kind of restraint is almost never present when the news media trumpet a new fossil find.  We only hear about “missing links” and how “X is the ancestor of Y” throughout the reports.

To be fair to Prothero, he does believe that ancestry can be verified if the fossil sample size is large enough.  In his own research on planktonic microfossils, he claims that there are enough layers of fossils to draw scientific conclusions about ancestry.

Planktonic microfossils aside, it is time that palentologists become more careful with their language and stop referring to new fossils in sensational terms.  In most cases, there is no way to determine ancestry; we can look at what features a new fossil shares with other taxa, but that is usually as far as we can go.

Evolution, Intelligent Design

Is Darwinian Evolution Falsifiable?

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Post Author: Bill Pratt

I have long suspected that it is not.  I was listening to another Unbelievable? podcast the other day which featured a debate between ID proponent Michael Behe and ID opponent Keith Fox – both are biochemists.  During the discussion Behe talked about the longest running lab experiment to test the effects of Darwinian evolution on E. coli.  Professor Richard Lenski has been growing trillions of E. coli over more than a decade and he has produced tens of thousands of generations.

According to Behe, the net effect of natural selection and random mutation on the E. coli has been mostly to break biological systems that were already in place.  No new complex systems have been formed by Darwinian evolution in the experiment.

Keith Fox agreed with Behe’s assessment of the experiment, but claimed that it did not prove anything about the limits of Darwinian evolution to produce complex new biological systems (which is a central claim of Darwinists).  Behe asked Fox, “If this experiment doesn’t prove anything about Darwinian evolution, then what kind of lab experiment could falsify Darwinian evolution?”  Fox’s answer: none.

According to Fox, lab experiments can never replicate the natural selection pressures that E. coli or any other organism face in the natural world.  These pressures can not be simulated in a lab.  It seems that the mechanisms of random mutation and natural selection must be assumed – they cannot be falsified by experimental biology.

What we have here is an unfalsifiable theory.  No matter what experiments are run to test Darwinian evolution, the results can never, according to Fox, disprove its ability to generate new biological systems.  Aren’t scientific theories supposed to be falsifiable?  Am I missing something?