The Scientific Validity of Evolution

Darwinian Evolution is an idea that springs from biology but has greatly impacted other areas of thought such as the social sciences, public policy, and some aspects are considered in cosmology. Because of its widespread influence I believe that it’s a good Idea to take a look evolutions scientific validity.

First of all I would like to clarify that evolution does not necessarily mandate a change in species. Evolution is a process occurring on a long continuum and an organism can fall into any particular place on that continuum over time. Also, to say that any particular creature is “more evolved” than another is meaningless. There is no ultimate goal that evolution is striving to achieve; it’s simply a process by which organisms that are best matched to their environment will survive and pass on their genes. These gene recombinations and mutations have, over many millions of years, resulted in organisms we call bears that have fur and other organisms we call giraffes that have long necks. Each of which is particularly suited to their environments (and just lucky enough to have had their genes passed down through the generations).

There are two key methods through which evolution takes place: genetic drift and natural selection. Most biologists like to state that genetic drift is the most random process. An organism can wantonly mate throughout its society and spread its genetic material - which will later be recombined with other genetic material - with arbitrary mutations occurring here and there sometimes. Thus the organisms DNA will “drift” through the environment by chance.

On the other hand, scientists like to point out that natural selection is not random at all and offers an element of predictability. For instance, let’s say that a snake is born with albinism. In the jungle it would be highly unlikely that this snake would survive because predators would easily be able to distinguish it from its environment. We would reasonably be able to predict that albino snakes will be targeted by predators and eventually most of the genes that cause albinism will be weeded out due to natural selection.

Once again, environment plays a key role. Now let’s assume that a volcano has erupted nearby and tossed white ashes all over this area of the jungle. Suddenly the white snakes have the advantage – now the darker colored snakes will be easy prey for predators. Assuming this happens over a long enough period, the albino snakes will find it easier to survive and pass along their genetic material therefore eventually becoming the more dominate type of snake.

From what we have seen of evolution so far, it is obvious that an organism’s chance for survival cannot be separated from the environment that it lives in. Because of this, evolution is tied not only into the organism itself, but also its surroundings – whether they are living or not. This is very significant and leads me to two problems:

The first problem is that evolution is extremely limited in its capacity to predict. The example of the albino snake is not farfetched. Many of those of you reading this probably remember the same thing happened with the peppered moth in Great Britain. It was perfectly logical to presume that a white snake had little chance of survival in a jungle – until we changed the environment. Natural selection would only allow us to predict up to a point. Predictability further falters when we factor in not only the environmental changes but the mutations and random recombination of the genes themselves. Stephen Jay Gould, the evolutionary biologist and paleontologist, has argued that because of the happenstance nature of evolution, if we were to go back in time and re-run evolution all over again, we would not recognize life on earth anymore. The fact that evolutionary changes happen over such a long period of time makes the limited-scope predictability of natural selection virtually useless.

The second problem is that everything can be explained through evolution. The philosopher Karl Popper is well noted for his stance that in order for a theory or proposition to be considered scientific it must be falsifiable. In other words, the core tenets of the theory must be logically testable and verifiable to be either true or false. Einstein’s theory of Relativity contains predictions and testable hypotheses that have been backed up through trials and experiments that have resulted in adding further validity to his ideas on the nature of light, gravity, and time. To contrast this, let’s look at evolution’s falsifiability. First of all, if an environmental change takes place, we can say that any effect on the organism (either negative or positive) is due to a concurrent change in its environment. If the environment holds steady, we can say that any changes in the organism are due to genetic drift and/or natural selection. No matter what happens, it is still considered evolution.

So, in order for a theory to be considered scientific it must offer predictability and falsifiability. Judging from the evidence so far, evolution does not present either of these. So what is evolution?

There is one cornerstone of human thought that also does not necessitate the need for scientific verification: religion.

Does evolution fit the definition of religion more so than it does the definition of scientific theory?

Just food for thought.

First of all Tortoise, your answer to my post is exactly the reason that I created my post to begin with. What are you really saying by “affect survival”? If an organism lives or dies its survival has been affected. You are defining evolution in terms that fit every possible situation: “show that mutations which affect survival positively NEVER happen” can also be read as: If a creature dies due to its genetic makeup, that is evolution; if a creature lives due to its genetic makeup that is evolution too.

Of course we do. This is the exact same statement as the last one. If an organism’s mutation causes it to die, than survival was affected; if an organism’s mutation causes it to live than its survival was affected. No matter what happens – it’s still evolution!

Another thing is that it is impossible to show that something will “positively NEVER happen”. This is the same type of argument that religious fundamentalists use as “proof” of Gods existence. Let me illustrate: If one could show that prayers are positively NEVER answered, God would be false. (Actually this does not prove anything either; God could still exist but not actively be involved in the modification of nature – much like Spinoza’s concept of God.)

The price of lettuce at the grocery store is dependent on the supply of oil in the Middle East. How often fish have sex is dependent on the gravitational pull of the moon. A dependency can be easily created between any two things. Ever played “Six Degrees of Kevin Bacon”?

As far as the fossil evidence goes, that really does not concern my problems. My problems deal with predictability and falsification – two essential elements of any scientific theory.

Fossil evidence is the act of putting together a theory after-the-fact. It is very simple to look at something after it has already occurred and create an explanation for why it is that way. As a matter of fact, religion does this all the time. If a prayer is not answered, the religious man would say that “it is not God’s will”, or, something along the lines of “I am a sinner and God is punishing me”.

We can conduct a test, though. Let us predict several small evolutionary events – based on evidence obtained so far through the “rather convincing” fossil record and if the majority of the predictions come true, than evolution has verified its claims. As a contrast, we can also have a group of religious people say several prayers and if the majority of the prayers are answered – or not – than we can compare the validity of evolution as it relates to the validity of religion.

I think that we both know that each instance will end up being a statistical crap-shoot.

I don’t recall saying that death was a mutation. However, genetic mutations could lead an organism to be at a disadvantage that would cause it to die out. Do you disagree with this?

Tortoise, you never used the term “positive”. You used the term “positively” as a synonym for certainty - as in mutations which affect survival certainly do happen.

You are using the word “positively” in two different ways with different meanings and now trying to equate the two.

If you had meant for the term to mean what you are now saying, it should have been written: "If one could show that positive mutations which affect survival NEVER happen, evolution would be false.”

Is this what you mean? Do I understand you correctly that you are saying only mutations that allow the organism to survive are considered to be evolution? Are you saying that chance mutations that cause an organism to die are NOT elements of evolution?

I just want to make sure I understand you this time.

Yeah, mutations can lead to a decrease in fitness, an increase, or no change at all. Good thing we have natural selection.

Mutation is the spark that ignites evolution i.e. it makes it happen - it cannot occur otherwise…

Natural selection seems non-existant now-a-days - it seems that others can now ‘buy into’ good genes with cold hard cash: which leaves the process unbalanced.

This is a summary of what you just stated:

  1. Neither positive, negative, nor “neutral” mutations should be considered as evolution.

  2. Also, neither negative nor neutral mutations should be considered even elements of evolution.

  3. This leaves only positive changes.

  4. Only genetic mutations that affect a “positive” boost in an organism’s potential for survival should be considered “evolution”.

Is this your stance?

  1. In-and-of-themselves, no. But over time?

  2. Silent mutations are nice for tracking evolution, see Woese, but they aren’t evolution really. And mutations that negatively effect fitness are selected out.

  3. Within various contexts, yes, increases in fitness drive evolution. Genetic drift and other factors play a role as well, of course.

  4. Huh? This statement literally makes no sense.

I understand 4 - it makes perfect sense…

Isn’t mutation and change the same thing?

For #4 substitute the word “boost” for “change”. Sorry if that derailed the brain train. I was being a little facetious.

Great! Now we are full circle back to my original post - still with neither of the issues I brought up being delt with.

You are reifying “species” in your OP. A common problem.

This is the only sentence in my OP where I use the term species:

Reifying generally means to treat something as real, which is not real.

I don’t really see where you comming from with your comment xunzian. Are you saying that speciation is not a real thing? Could you clarify?

The sentence was also used as an aside for added information and doesn’t really pertain to my two original problems.

Give me a definition of species and we’ll talk. I’ve talked about this sort of thing numerous times before. Here is a good example. Once you’ve digested that, you’ll see that evolution is both highly predictive and disprovable (but it has not been disproven thus far).

I’m kind f an evolutionary ‘expert’ (though take the term with a grain of salt) it just means that for over 10 years now i’ve been grossly educated in evolution and most of its subsciences (and most of biology in general) and my first problem I guess is that evolution has some extremely predictable patterns and that evolution in general is a massive source of predictions.

We can’t predict the actions of the environment, however we can predict the ecological balances or imbalances that would lead for a species to produce certain adaptations. We could make similiar predictions about environments.

Also, we can make predictions about what evolutionary pressures animals must have faced, both by their behavorial (Ecology, neuroethology) and physical structures.

We can make predictions about the type of things evolution can do, like re-use successful strats among different species that arrived there via different evolutionary paths.

It makes it hard to understand for people who are evolved to deal with smaler stretches of time, it doesn’t hurt its predictive power.

Anyway, I have the feeling that you put together a nice post for no other reason then to suggest evolution can’t be falsifiable, has no prediction power (a bullshit claim) and is a religion.

When people said that whales were mammals gone back to the sea, do you think there is no predictive power there? Why, look at the genes of the whale and then look at its next closest living relative.

Evolution makes continously predictions, its a source of a different and very powerful lens at which to look through biology.
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Predictions about adaptations are also everywhere, the prediction that female pregnancy sickness is an aversion to chemicals that can harm a developing fetus is somthing that is a prediction about pregnancy sickness: we should find the chemicals that cause fetal harm, correlating very strongly with a pregnant woman puking her guts up.

(Perhaps a good reason why many medications that simply get rid of pregnancy sickness cause horrible birth defects)

Think of this and then think of thousands of other predictive claims, some that have born out massive evidence:

Humans should have: Kin detection mechanisms, anti-cuckholdry mechanisms, cheater-detection mechanisms, parental investment mechanisms etc etc etc etc, all these predictions come from SIMPLY thinking about the area in which huumans evolved, not only do we get the predictions, its that the evolutionary view is one of the greatest prediction churning out machines in science, and it is largely largely largely successful.

Facial detection mechanisms, agency detection mechanisms, not only do we get predictions, but we can correlate this type of behavior and ask how it works/evolved by brain scans and the new science of evolutionary cognitive neuroscience.

evolution is falsifiable in a lot of ways, for one find an organism that has irreducible complexity, that could not have been created or any part of it created by simple step by step change.

And please please don’t bother trying to provide examples of irreducible complexity, it hurts my brain and my opinion of others who do it pretty consistantly. Take my word, they don’t exist or haven’t been found as of yet.

Secondly, we don’t see rabbits in the fossil record before they evolved, which could put a pretty bighole in the entire idea.

Really, i’d love threads like this to be deleted on creation unless the person has a very powerful arguement against the current evidence for evolution (which is out of control massive)

Its so mentally degrading, not just for me, or educated people, but for everyone. There.is.no.debate.about.whether.or.not.evolution.happens.

If you want to have a meaningful discussion on evolution, this just isn’t it.

(theres enough evidence in one book, to make it so that a person would have to become a scientist, have access to labs and etc, and spend most of their lives trying to correct the claims and still fail, and that might be for a couple of claims the book makes on the first few chapters.

Try doing this for mountains of books, the task, within one lifetime, isn’t going to happen, so until a great group of people spend a century cutting up evolution with real arguements, we should take it as the fact that it is.

N ot only does evolution explain things very economically, but if you want to suggest somthming else you’ll have to explain why all the evidence for evolution to begin with, any additional theory or scientific model has the added trouble of explaining away evolution (on top of the near impossible task of showing it has faults or showing that another model with more evidence exists).

I’m interested in truth-claims and propositions, this isn’t even one of those, its a quasi-proposition seemingly only vunerable to the emotional satisfaction of the need that created it.

oh, btw, people don’t believe in darwinian evolution so much as neo-darwinian evolution, theres a pretty HUGE gap, there.

As they say, the evidence for evolution is overwhelming. Also, it logically follows from the simple facts of mutation and reproduction. That evolution as described is a factor, I would think, is undeniable. But there are a couple of assumptions I would contest: 1. that change only happens by random mutation, and 2. that every aspect of the development of every species is accounted for by evolution as it’s currently understood. In other words, I’m agreeing with you - the problem is it’s just assumed that “if we could take into account all the variables, our models of evolution would predict x…” for any x which is something we observe in some species. In fact, we can’t even come close to simulating an ecosystem, and if evolution as currently defined were largely insufficient to explain the species that are alive today we wouldn’t know it. I believe they predicted, based on quantum mechanics, something about the behavior of steam over water before they even realized that it should have been impossible by the old Newtonian physics. It just goes to show that the presumptions that known theories are all-pervasive, that they explain everything observable in the world, are just leaps of faith…

Define what you mean.

First of all scientist/science is the first to admit where the conjecture is no longer rational or based on evidence, science knows evolutionary limits then better then anyone critisizing it.

I mean that, since we cannot simulate an entire ecosystem based on evolutionary theory and see whether what we have now would arise in such a simulation, we can’t know whether evolutionary theory is sufficient to explain anything. We have no way of knowing whether current evolutionary theory, that is, the basic paradigm, is sufficient for explaining what we have now, we just assume that what we see is covered by it.

Let’s take a thought experiment. Assume that everything that exists now does fall under a current evolutionary explanation. Then add a species whose evolution was also influenced by other factors–we have no way of telling the difference. By extension, all species alive today could have their evolution influenced by other factors and we wouldn’t know it. It could even be patently absurd to think that our paradigm could explain it, and totally obvious to someone 1,000 times smarter than we are.

limits? what limits does it recognize?

the thing about evolutionary theory is it’s not really falsifiable. you said ‘where the conjecture is no longer … based on evidence’, but new evidence won’t tell you anything about its limitations – the evidence is here, we just don’t know how to read it.

Apparently several posts have happened since I last looked at this. I’ll do my best to address the comments within the short amount of time I have.
Before we continue I would like to clear up a few things. First of all, I am not a creationist, I am not an “ID’er”, and I do not adhere to any particular religious belief. I have long believed that evolution is a real, concrete, highly established scientific theory. Through my studies, though, I came across the two problems that I presented in my original post. I feel that the problems should be of real concern to any legitimate scientific theory. Now with that out of the way…

Well, I guess we won’t be talking Xun because I could care less about the definition of species. As I said before – to reiterate my déjà vu all over again – species has nothing to do with my argument. The only time I used the term in my OP was to say that it was not necessary to use that term. The culmination of the posts within the link that you sent me was that you, as an individual, choose not to define species. I’m trying to refrain from being blunt, but – so what?

Cyrene, you have made a good deal of posts so I will try to use my remaining time addressing your comments:

I’m sorry but this made me laugh. I thought of Ron Bergundy saying “I’m kind of a big deal.” I believe you though.

Ok, what are some current, specific preditions?

(emphasis mine)
This is ex post facto. This is not a prediction, it is an observation. You are observing what has already occurred and forming an opinion about it.

Thank you for the compliment. Yes these were the two problems that I listed and therefore the purpose of my post. A religion is a belief system generally characterized by adherents who use doctrines and dogma to justify after-the-fact events and fail to predict future events. Yes, sometimes evolution falls into this definition.

No, there is no predictive power there. Once again it was an observation that occurred after the event. Lab rats, pigs, chimps, and humans have similar genes as well. Care to place a bet on which one will be aquatic in the future?

Not a prediction. We observed that females were getting sick and found out what was causing it. Would you also say that a coroner predicted a person’s death at the autopsy?

I really like this argument because I have an immediate example: blog.mlive.com/chronicle/2007/12 … om_at.html
An adopted son searches for his birth mother and discovers that she is his co-worker at a Lowes home remodeling store. Shouldn’t his “kin detection system” have predicted this? I guess his kin detection system turned out to be an online adoption database. (Now you could say the fact that the two of them worked at the same store is evidence that the kin detection system was an active instinct that was only manifest in the subconscious – but you would be treading into psychoanalysis land then and I’m not so sure that’s where you want to be.)

Also, how do I turn on my cheater detector when I’m playing poker? That would really come in handy.

How it evolved? If you want a scientific theory, tell me how it will evolve. Then you’ve got yourself a deal. Until then, it’s just a history lesson.

If your brain hurts, take an Advil. I never said anything about irreducible complexity did I? Even an electron does not have irreducible complexity (that we know of).

Basically, what you just said there is that if it is not in the fossil record, it didn’t exist. Most biologists would disagree with you on this – but you probably already know that since you are an expert. It is indeed a rare event for an organism to be fossilized – it’s even rarer for us to find the fossils. Many evolutionary biologists would say that there have been far more living organisms than we will ever know about simply because they never made it into the fossil record.

Of all the posts, this really concerns me. Because we disagree, you would like to see me lose my First Ammendment rights? As Richard Dawkins says, “they’re just words.” This is exactly the kind of diatribe that I would expect from a Christian or Muslim if I had questioned their belief system. Thank you for reinforcing my original theses.

To conclude, if you want to counter my arguments you must do 2 things to prove that evolution is indeed a scientific theory:
1) Make a series of specific evolutionary predictions and verify their occurrences. The same standard holds true for math and physics. Specific predictions, repeated experiments, consistent results. I would expect no less.

2) Provide a constant that holds steady throughout the theory. Relativity says that light has a speed limit of 186,000 miles per second through a vacuum. If this changes, we would seriously have to reevaluate our concept of physics. Where is evolution’s “speed limit”? Where is its E=MC2
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Also, I’m sorry if I come across as an ass sometimes; when I find humor I like to point it out and it comes across as sarcastic (which it usually is). I appologize if I offend anyone. :smiley: