Evaluating Evolution

[Zosimus]

Many Christians believe that evolution is a fairy tale invented by atheists to let them avoid moral responsibility for their actions. Others say that evolution is “only a theory.” However, some Evolution apologists say that evolution is a fact. Others say that evolution is a theory, but that scientific theories are different from regular theories. Still others will say that evolution has been proved.

It is impossible to know who is right without understanding the definition of evolution. Biological evolution, as explained in college textbooks, is usually defined as a change in the frequency of alleles from generation to generation. If this definition of evolution is used, then evolution is merely a fact of life. Even if we postulate Adam and Eve, and believe that all their sons were exactly like Adam and all their daughters were exactly like Eve, the frequency of alleles in the population will still change unless they had the same number of sons as daughters.

However, this is not the definition of “evolution” that is usually tossed around in a forum like this. Here evolution is normally some form of neo-Darwinism. This belief set is usually composed of at least three (and sometimes four) distinct theories. Natural selection, sometimes called the “survival of the fittest”, common ancestry, the belief that all living things share a common ancestor, and the previously-mentioned evolution. Not all evolutionary apologists agree whether abiogenesis, the belief that life arose spontaneously from non-living substances, is a part of neo-Darwinism.

The only really objectionable parts of neo-Darwinism, from a religious point of view, are the theories of abiogenesis and common descent. Most creationists do not object to the idea that a horse born with only three legs is unlikely to survive and breed. Natural selection, therefore, is not usually controversial.

The same cannot be said for abiogenesis and common descent. Many creationists are Christians and therefore believe not only that God created all life on Earth, but also that Adam was created in God’s image. This would establish a special relationship between God and man. From this starting point Christian theology can argue that a God would be willing to personally suffer great anguish in order to atone for the sins of beings that he shares a special relationship with.

Since abiogenesis is not universally accepted as being part of neo-Darwinism (hereinafter called “evolution”) there is perhaps little to say that has not already been said. A view of even “simple” single-celled life shows that it is extremely complex. The probability of one of these factories self-assembling is so remote as to be beyond the realm of possibility. Abiogenesis apologists normally fall back on theories of even simpler life that was the precursor of the simplest cells we see now, but which has disappeared without leaving a trace. While such theories cannot be ruled out automatically, an argument could easily be made that such theories are untestable and therefore unscientific.

Most of the arguing about evolution revolves around common descent. A common argument advanced by evolutionary apologists is that humans and chimps share a common ancestor. One recent study, performed in 2005, showed that chimps and humans have about 96 percent of their genes in common. It is often claimed that this is proof of common descent.
The argument usually sounds something like this: Science believes that humans and chimps share a common ancestor. If this is true, then humans and chimps will have many similarities. DNA tests have shown that humans and chimps are extremely similar. Therefore we know that humans and chimps do indeed share a common ancestor.

Unfortunately, this argument contains a logical flaw. The logical fallacy known as “affirming the consequent” is employed to draw the conclusion. While it is true that if common descent is true, chimps and humans must have great similarity in terms of DNA, the reverse is not true. To illustrate why this is, let us parallel the reasoning. We theorize that Bill Gates owns Fort Knox. From this we deduce that he will be rich. We see that there is abundant reason to believe that he is rich, and therefore we conclude that he must own Fort Knox. The assumption being made is that the only way he could be rich is if he owned Fort Knox. Other possible explanations for his wealth are ruled out a priori.

Some evolutionary apologists are aware of this flaw and attempt to fix up the argument by rephrasing it thus: The probability of human and chimp DNA being this similar purely by chance is astronomical. Accordingly, humans and chimps must share a common ancestor. Accordingly we see the assumption being made that: a) humans and chimps share a common ancestor, or b) the similarity in DNA is a product of chance alone. The third option c) an intelligent and/or divine designer created both DNA sets not considered.

Hence I conclude that evolution has not been proved, but is simply a theory. It may be right, or it may be wrong. There are no known reasons to prefer this theory over any other, and accordingly I remain agnostic on the subject of evolution.

 

[lasthero]

. A view of even “simple” single-celled life shows that it is extremely complex.

Please define 'complex', and show how you determine in any objective fashion that single-celled life is such a thing. How do you determine how complex something is? How are you measuring it?

Hence I conclude that evolution has not been proved, but is simply a theory.

Everything in science is 'simply a theory'. A theory is the highest form of knowledge you can get in science short of mathematics. Plate tectonics are a theory. Gravity is a theory. Cells are theory. It's all theory. Theories do not graduate into facts. They are composed of facts.

Yes, evolution hasn't been proven. Science doesn't deal in proof. Proof is absolute. If something is proven, there's nothing else to learn. It deals, instead, with evidence.

 

[Loudmouth]

Most of the arguing about evolution revolves around common descent. A common argument advanced by evolutionary apologists is that humans and chimps share a common ancestor. One recent study, performed in 2005, showed that chimps and humans have about 96 percent of their genes in common. It is often claimed that this is proof of common descent.
The argument usually sounds something like this: Science believes that humans and chimps share a common ancestor. If this is true, then humans and chimps will have many similarities. DNA tests have shown that humans and chimps are extremely similar. Therefore we know that humans and chimps do indeed share a common ancestor.

Unfortunately, this argument contains a logical flaw. The logical fallacy known as “affirming the consequent” is employed to draw the conclusion. While it is true that if common descent is true, chimps and humans must have great similarity in terms of DNA, the reverse is not true. To illustrate why this is, let us parallel the reasoning. We theorize that Bill Gates owns Fort Knox. From this we deduce that he will be rich. We see that there is abundant reason to believe that he is rich, and therefore we conclude that he must own Fort Knox. The assumption being made is that the only way he could be rich is if he owned Fort Knox. Other possible explanations for his wealth are ruled out a priori.

What you fail to realize is that it is not simply the similarity between chimps and humans that evidences common ancestry and evolution. It is the PATTERN of similarity that evidences evolution and common ancestry. That pattern is a nested hierarchy.

29+ Evidences for Macroevolution: Part 1

What we observe is that evolution produces a nested hierarchy. We also observe that intelligent design of separately created designs does not produce a nested hierarchy. For example, different cars share features, but cars do not fall into a nested hierarchy. There is absolutely no reason why a designer would force his designs to fall into a nested hierarchy. The only process that necessitates a nested hierarchy is evolution.

Therefore, when we see a nested hierarchy it is evidence that evolution occurred in the past.

Some evolutionary apologists are aware of this flaw and attempt to fix up the argument by rephrasing it thus: The probability of human and chimp DNA being this similar purely by chance is astronomical. Accordingly, humans and chimps must share a common ancestor. Accordingly we see the assumption being made that: a) humans and chimps share a common ancestor, or b) the similarity in DNA is a product of chance alone. The third option c) an intelligent and/or divine designer created both DNA sets not considered.

An intelligent designer is considered. If intelligent design is the source for designs in nature then we should not see a nested hierarchy. That is the test. Intelligent design fails this test. Instead, we see the exact pattern of similarity that we would expect from evolution.

Hence I conclude that evolution has not been proved, but is simply a theory. It may be right, or it may be wrong. There are no known reasons to prefer this theory over any other, and accordingly I remain agnostic on the subject of evolution.

Are you also of the opinion that we should free everyone from jail that was convicted on the basis of forensic evidence because God could have planted the evidence at the crime scene?

 

[JWGU]

This is an overall logical post, which is nice, but there are a few statements that I would argue with...

Since abiogenesis is not universally accepted as being part of neo-Darwinism (hereinafter called “evolution&#8221 there is perhaps little to say that has not already been said. A view of even “simple” single-celled life shows that it is extremely complex. The probability of one of these factories self-assembling is so remote as to be beyond the realm of possibility. Abiogenesis apologists normally fall back on theories of even simpler life that was the precursor of the simplest cells we see now, but which has disappeared without leaving a trace. While such theories cannot be ruled out automatically, an argument could easily be made that such theories are untestable and therefore unscientific.

These theories are not totally untestable (or at least, unfalsifiable). In fact, most scientific(ish) arguments against earthly abiogensis focus on finding experimental evidence that, e.g., the RNA world simply could not have occurred with the mixture of chemicals available on early Earth. Thus far, the experimental evidence has been increasingly in favor of the idea that earthly abiogensis is remarkably plausible. As you correctly noted, that doesn't make it fact, but as you also correctly noted it is not part of the theory of evolution anyway A bigger concern for those maintaining that abiogenesis did not occur on earth is explaining where and how it did occur (we know it happened at some point, assuming a finite universe, since life does now exist). It is in any case an almost entirely academic question; we are talking about something that may have happened once billions of years ago, and while researching the processes that could have produced it may be useful, it is unlikely that knowing whether that was how it happened will ever lead to any significant or useful human innovations.

Some evolutionary apologists are aware of this flaw and attempt to fix up the argument by rephrasing it thus: The probability of human and chimp DNA being this similar purely by chance is astronomical. Accordingly, humans and chimps must share a common ancestor. Accordingly we see the assumption being made that: a) humans and chimps share a common ancestor, or b) the similarity in DNA is a product of chance alone. The third option c) an intelligent and/or divine designer created both DNA sets not considered.

The "third option" is not considered because it is simply not a scientific hypothesis. It is unfalsifiable and therefore untestable. Loudmouth notes that an intelligent designer in the mold of us as humans is quite falsifiable, and has been falsified, but people continue to treat this as a viable option because they can simply posit that the designer was planting evidence to fool us. There is no way of us ever being able to determine that (c) is false and it cannot help us make any future predictions. That doesn't mean it is false but it does mean it is useless, from a scientific perspective.

Finally, saying something is a theory and could be wrong (accurate) does not mean there are no reasons to prefer a theory over other theories. Theories can have dramatically different probabilities. The probability that the theory of evolution (common descent) is true, based on what we currently know, is extremely high (I would round it to 100%).

 

[Zosimus]

What you fail to realize is that it is not simply the similarity between chimps and humans that evidences common ancestry and evolution. It is the PATTERN of similarity that evidences evolution and common ancestry. That pattern is a nested hierarchy.

(link removed due to post count problems)

What we observe is that evolution produces a nested hierarchy. We also observe that intelligent design of separately created designs does not produce a nested hierarchy. For example, different cars share features, but cars do not fall into a nested hierarchy. There is absolutely no reason why a designer would force his designs to fall into a nested hierarchy. The only process that necessitates a nested hierarchy is evolution.

Therefore, when we see a nested hierarchy it is evidence that evolution occurred in the past.

Affirming the Consequent

The “affirming the consequent” logical fallacy occurs when someone inverts the normal logical operation order. The normal deductive method of reasoning goes like this:

All men are mortal (i.e., If X is a man, then X is mortal).
Socrates is a man.
Therefore Socrates is mortal.

The affirming the consequent logical fallacy normally runs like this:

All men are mortal.
My dog Fido is mortal.
Therefore my dog Fido is a man.

With this in mind, let us evaluate your logical claim.

Evolution produces nested hierarchies (If Evolution, then nested hierarchies).
We observe nested hierarchies in nature.
Therefore evolution is true.

This is a classic example of the “affirming the consequent” logical fallacy.

 

[Loudmouth]

Affirming the Consequent

The “affirming the consequent” logical fallacy occurs when someone inverts the normal logical operation order. The normal deductive method of reasoning goes like this:

All men are mortal (i.e., If X is a man, then X is mortal).
Socrates is a man.
Therefore Socrates is mortal.

The affirming the consequent logical fallacy normally runs like this:

All men are mortal.
My dog Fido is mortal.
Therefore my dog Fido is a man.

With this in mind, let us evaluate your logical claim.

Evolution produces nested hierarchies (If Evolution, then nested hierarchies).
We observe nested hierarchies in nature.
Therefore evolution is true.

This is a classic example of the “affirming the consequent” logical fallacy.

It's called the scientific method. That's how it works. Are you really telling us that the scientific method is invalid? Are you saying that this method is invalid?

Ask a Question
Do Background Research
Construct a Hypothesis
Test Your Hypothesis by Doing an Experiment
Analyze Your Data and Draw a Conclusion
Communicate Your Results

Are you saying that we should free everyone from jail convicted on the weight of forensic evidence because God could have planted the evidence at the crime scene?

 

[JWGU]

Affirming the Consequent

The “affirming the consequent” logical fallacy occurs when someone inverts the normal logical operation order. The normal deductive method of reasoning goes like this:

All men are mortal (i.e., If X is a man, then X is mortal).
Socrates is a man.
Therefore Socrates is mortal.

The affirming the consequent logical fallacy normally runs like this:

All men are mortal.
My dog Fido is mortal.
Therefore my dog Fido is a man.

With this in mind, let us evaluate your logical claim.

Evolution produces nested hierarchies (If Evolution, then nested hierarchies).
We observe nested hierarchies in nature.
Therefore evolution is true.

This is a classic example of the “affirming the consequent” logical fallacy.

We have additional evidence for common descent, beyond nested hierarchies. Lots and lots of additional evidence. The link you were provided by Loudmouth summarizes a lot of it. I also think you may be confusing simple, non-probabilistic first order logic (which only deals in absolute certainties) with science, which deals in probabilities. In science, we create hypotheses, collect evidence, run statistical tests on the evidence, and see how well it matches our prior model. We then provide probabilities that a significant deviation from the model occurred. Provided that at least some of the claims were made before the model fit was tested, this is a rigorous, logical and mathematical process, but it quite importantly does not deal in certainties. That is why statistics are rather more complex than first order logic

 

[lasthero]

Evolution produces nested hierarchies (If Evolution, then nested hierarchies).
We observe nested hierarchies in nature.
Therefore evolution is true.

While I'm not exactly an expert on fallacies, I'm pretty sure this would only count as such if there was, in fact, something else that was known to create nested hierachies besides evolution. Since evolution is the only thing that's been observed to do this, it's a logical conclusion.

It's more like saying

Only my mother has the password to this computer.
The computer is unlocked.
Therefore my mother unlocked the computer.

It's possible someone else did - say, by stealing the code - but the most logical conclusion is that my mother simply unlocked the computer herself, because she's the only one I'm aware of that knows the password.

 

[Zosimus]

Theories do not graduate into facts. They are composed of facts.

Yes, evolution hasn't been proven. Science doesn't deal in proof. Proof is absolute. If something is proven, there's nothing else to learn. It deals, instead, with evidence.

Theories are not composed of facts. Theories are attempts to explain why specific real or imagined similarities occur. For example, it has been observed many times that electromagnetic radiation can propagate through the vacuum of space. One possible theory that space is not actually empty, but rather contains a sort of luminiferous aether through which the electromagnetic radiation can propagate. This is a theory, a scientific theory, and a valid theory. It is simply not accepted by the vast majority of the world, whether they work in the scientific field or not.

 

[JWGU]

Theories are not composed of facts. Theories are attempts to explain why specific real or imagined similarities occur. For example, it has been observed many times that electromagnetic radiation can propagate through the vacuum of space. One possible theory that space is not actually empty, but rather contains a sort of luminiferous aether through which the electromagnetic radiation can propagate. This is a theory, a scientific theory, and a valid theory. It is simply not accepted by the vast majority of the world, whether they work in the scientific field or not.

You're being somewhat disingenuous if you assert that the aether theory is just not accepted for some arbitrary reason, as in fact it was the commonly accepted theory for a good, long while. Fortunately, because it was a legitimate scientific theory, it was falsifiable. It was tested, and subsequently falsified. While the theory may be consistent (no internal contradictions), it is not sound (it is based on falsified premises).

In an attempt to balance this post--you have thus far not said anything specifically illogical except that all theories are equally probable, and I applaud you for that. It is very difficult to maintain a rigorous and logical approach when arguing against something as well-evidenced as common descent!

 

[lasthero]

Theories are not composed of facts.

Yes, they are.

A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. Such fact-supported theories are not "guesses" but reliable accounts of the real world. The theory of biological evolution is more than "just a theory." It is as factual an explanation of the universe as the atomic theory of matter or the germ theory of disease. Our understanding of gravity is still a work in progress. But the phenomenon of gravity, like evolution, is an accepted fac

AAAS - Evolution Resources

Theories are attempts to explain why specific real or imagined similarities occur.

That's the colloquial definition. We're dealing with scientific theories.

 

[Loudmouth]

Theories are not composed of facts.

They most assuredly are.

"Well, evolution is a theory. It is also a fact. And facts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world's data. Theories are structures of ideas that explain and interpret facts. Facts do not go away when scientists debate rival theories to explain them. Einstein's theory of gravitation replaced Newton's, but apples did not suspend themselves in mid-air, pending the outcome. And humans evolved from apelike ancestors whether they did so by Darwin's proposed mechanism or by some other, yet to be discovered."--Stephen Jay Gould, "Evolution as Fact and Theory"
Stephen Jay Gould, "Evolution as Fact and Theory" 1994

I would suggest that you read the entire essay. It isn't that long.

Theories are attempts to explain why specific real or imagined similarities occur.

Those similarities are not imagined. They are facts. It is a fact that 96% of the chimp and human genomes are the same. It is a fact that we share over 200,000 ERV's at the same location in our genomes while only differing by a relative handful. It is a fact that fossils have a mixture of modern human and basal ape features.

For example, it has been observed many times that electromagnetic radiation can propagate through the vacuum of space. One possible theory that space is not actually empty, but rather contains a sort of luminiferous aether through which the electromagnetic radiation
can propagate.

This theory was falsified by the Michelson-Morley experiment, and other experiments.

Michelson–Morley experiment - Wikipedia, the free encyclopedia

That is how science works. You create a hypothesis and a null hypothesis. You then design an experiment that tests both the hypothesis and null hypothesis. As for the luminiferous aether, the null hypothesis was confirmed and the aether was falsified.

 

[Zosimus]

The "third option" is not considered because it is simply not a scientific hypothesis. It is unfalsifiable and therefore untestable.

What you are basically saying is that science is ill-equipped to evaluate metaphysical arguments. You are merely trying to reframe that into being a defect for the theory in question, as opposed to a defect in science.

Finally, saying something is a theory and could be wrong (accurate) does not mean there are no reasons to prefer a theory over other theories. Theories can have dramatically different probabilities. The probability that the theory of evolution (common descent) is true, based on what we currently know, is extremely high (I would round it to 100%).

Please provide the mathematical formula you have used to calculate the probability of common descent.

 

[Zosimus]

It's called the scientific method. That's how it works. Are you really telling us that the scientific method is invalid? Are you saying that this method is invalid?

Ask a Question
Do Background Research
Construct a Hypothesis
Test Your Hypothesis by Doing an Experiment
Analyze Your Data and Draw a Conclusion
Communicate Your Results

Are you saying that we should free everyone from jail convicted on the weight of forensic evidence because God could have planted the evidence at the crime scene?

First of all, the scientific method is a myth. Scientists were doing science before the scientific method was dreamed up. Additionally, scientists do not use the scientific method to do research. For example, should the scientific method be used as a test of what is and is not scientific, then astronomers would not be scientists as they never do experiments - they merely observe the heavens.

Second, yes, the scientific method is invalid. Let us take a simple example. I hypothesize that giving vitamin C to people will cure them of colds. I try this theory on 100 people and find that 100 percent of them are cured after 5 days' time. Have I therefore proved that vitamin C is effective? I hope you can see that the answer is no. Most cold sufferers recover after 5 days' time without any intervention of any kind. This is why clinical trials require randomized, double-blind placebo-controlled studies. Even then, many of them are wrong.

 

[Loudmouth]

What you are basically saying is that science is ill-equipped to evaluate metaphysical arguments.

Science is a metaphysical system. More precisely, it is a methodology. Whether you give credence to the usefulness of the methodology is up to you, but it is hard to ignore the success that this methodology has had over the last 300 years.

Ultimately, we use science because it works, not because of some existential metaphysical argument. What you are arguing against is not evolution. You are arguing that we abandon science altogether.

You are merely trying to reframe that into being a defect for the theory in question, as opposed to a defect in science.

Your accusations of affirming the consequent applies to the scientific method itself. You are the one framing your argument as a refutation of the entirety of science.

 

[Loudmouth]

First of all, the scientific method is a myth. Scientists were doing science before the scientific method was dreamed up.

If they were doing science then they were using the scientific method. It isn't a myth.

If your argument is going to be that science doesn't exist, then you can stop here.

Additionally, scientists do not use the scientific method to do research. For example, should the scientific method be used as a test of what is and is not scientific, then astronomers would not be scientists as they never do experiments - they merely observe the heavens.

Observing the heavens in a systematic manner is an experiment when those systematic observations are able to support or falsify a hypothesis.

Second, yes, the scientific method is invalid. Let us take a simple example. I hypothesize that giving vitamin C to people will cure them of colds. I try this theory on 100 people and find that 100 percent of them are cured after 5 days' time. Have I therefore proved that vitamin C is effective?

What is your null hypothesis, and how did your experiment test it? If you want to claim that the scientific method is invalid, at least use the scientific method.

 

[lasthero]

then astronomers would not be scientists as they never do experiments - they merely observe the heavens.

Then what is this?

Experimental Astronomy - Springer

What's this book about?

http://www.amazon.com/Space-Astronomy-Experiments-Facts-Science/dp/0816078092

What are these guys doing?

http://phys.org/news/2013-09-balloon-borne-astronomy-x-calibur-window.html

 

[Zosimus]

While I'm not exactly an expert on fallacies, I'm pretty sure this would only count as such if there was, in fact, something else that was known to create nested hierachies besides evolution. Since evolution is the only thing that's been observed to do this, it's a logical conclusion.

It's more like saying

Only my mother has the password to this computer.
The computer is unlocked.
Therefore my mother unlocked the computer.

It's possible someone else did - say, by stealing the code - but the most logical conclusion is that my mother simply unlocked the computer herself, because she's the only one I'm aware of that knows the password.

While I do not deny that people do engage in the exact logical thinking you have outlined above, this logical pattern is not valid. It is the "argument from ignorance" logical fallacy.

Imagine that we postulate an ancient civilization that notes that people regularly get sick. It is postulated that they become sick because they have "bad blood" and leeches are applied to remove the bad blood. Leeches are somewhat effective and so the bad blood theory is widely accepted. One day a person is there and says, "You know, I have my doubts about the bad blood theory."

To which the medicine man says, "All right, what's your theory?"

"I don't have one," the person admits. "All I'm saying is that the theory you have doesn't convince me."

"Since there is nothing else known to create disease," says the medicine man, "You must accept the bad blood theory."

A subset of this logical fallacy is called the "God of the Gaps" fallacy. The argument goes like this: "Since there is nothing else known to cause big bangs, you must accept that God created the universe by causing the Big Bang." If evolution apologists do not accept this argument, why would they accept yours?

 

[lasthero]

While I do not deny that people do engage in the exact logical thinking you have outlined above, this logical pattern is not valid. It is the "argument from ignorance" logical fallacy.

Imagine that we postulate an ancient civilization that notes that people regularly get sick. It is postulated that they become sick because they have "bad blood" and leeches are applied to remove the bad blood. Leeches are somewhat effective and so the bad blood theory is widely accepted. One day a person is there and says, "You know, I have my doubts about the bad blood theory."

To which the medicine man says, "All right, what's your theory?"

"I don't have one," the person admits. "All I'm saying is that the theory you have doesn't convince me."

"Since there is nothing else known to create disease," says the medicine man, "You must accept the bad blood theory."

A subset of this logical fallacy is called the "God of the Gaps" fallacy. The argument goes like this: "Since there is nothing else known to cause big bangs, you must accept that God created the universe by causing the Big Bang." If evolution apologists do not accept this argument, why would they accept yours?

No one is saying you have to accept that evolution creates nested hierachies. But all the evidence points towards that, and points towards nothing else. If you have a separate idea, please demonstrate it, and then we can talk about it.

 

[Zosimus]

You're being somewhat disingenuous if you assert that the aether theory is just not accepted for some arbitrary reason, as in fact it was the commonly accepted theory for a good, long while. Fortunately, because it was a legitimate scientific theory, it was falsifiable. It was (link removed because of post count issues).

In an attempt to balance this post--you have thus far not said anything specifically illogical except that all theories are equally probable, and I applaud you for that. It is very difficult to maintain a rigorous and logical approach when arguing against something as well-evidenced as common descent!

As I have already pointed out, the evidence that was provided in favor of common descent is a logical fallacy.

You seem to be of the opinion that one logical fallacy proves nothing, but that a large number of them, when analyzed statistically, provides 99 percent certainty.