A defence of evolution

This is a long entry. For that I apologise.

An open letter to a friend...

   I know, it's all my fault. I started it with that comment in your blog, which I knew was ill-advised when I typed it. I should have been smarter than that, and deleted the bit about the Bible before I clicked publish. But I didn't, and you replied:

Every human plot ever written is in there. It was God inspired. No other book has made the top 100 list every year since it was written. It now seems that what was deemed fiction is being proven. Scientifically. All the good parts went to the guys.

It's a constant wonder and sometimes a puzzle but it speaks to today as much as it did to the time when it was written, a document for living.

And I replied to that:

"It now seems that what was deemed fiction is being proven. Scientifically."
 
I am curious exactly what you mean by that. Could you explain?

And then you replied:

Didn't you hear? The entire theory of evolution was a hoax! Man has not evolved in thousands and thousands of years, we will never evolve, we'll just find new ways of killing ourselves off! The earth is younger than we thought! Carbon dating is unproven and dinosaurs are referenced in the bible.

To which I again replied:

I can only assume you are joking.

To which you replied:

For someone into science fiction I would think that your analytical mind would want proof of everything. Why would you accept theory as fact? There is no proven evidence of man's evolving into anything for thousands of years. We did not descend from animals, if we did, prove it.

There is no proof of the earth's age.

Carbon dating is an unproven method. Show me anywhere scientific or otherwise that the claim is foolproof.

I believe in science when it proves itself.
So far, nothing and if you look at the facts and I'm not trying to argue, just show me facts. Proven facts.

And here we are.

   Normally, I would back off from this conversation at this point, as I wish to put friendship ahead of potentially flammable discussions about religion. I want to continue this one a little bit for three reasons.

1) I still think it is possible, even likely, that you are pulling my leg.

2) This will make a great journal entry.

3) This subject is too damn important to just let it slide by.

   Please note that what follows is, in no way, an attack on religion. It is merely a defence of science. I believe that the two need not be mutually incompatible.

   I would like to address these points one at a time, starting with your question about accepting theory as fact. I have to guess that the theory you are referring to is the theory of evolution. As a starting point, it is important to define terms. When scientists use the word theory, they have a very different definition of the word than when you and I use it casually in a non-scientific conversation.
   The word theory, used in a non scientific sense is usually understood to mean a guess, or supposition about something, and may or may not be backed up by any evidence. For example, I have a theory that you did not come up with these arguments on your own, rather you read them in some Christian literature, or heard them at a meeting or a presentation of some kind. I have no evidence to support that theory. I am only guessing, based on the fact that your statements closely resemble well known creationist propaganda that has been around for years and years.
   A scientist, however, would not call that a theory. He might call that a hypothesis. Then, he might devote years of study to the matter, collecting evidence in the field, designing and conducting experiments attempting to falsify the hypothesis, and refining it based on the results of those experiments and the evidence that he discovers. He might then publish the results of his years of study in a scientific journal, where it can be read, considered and discussed by other scientists.
   Those other scientists might then attempt to duplicate his experimental results. They might pore over his evidence, looking for inconsistencies. They might go into the field too, in an attempt to discover their own evidence that would either support or dispute the hypothesis of their peer. They might also publish their results, and a worldwide dialogue on the topic could be entered into. New evidence might come forward which only partially supported the hypothesis, and it would need to be altered to take that new evidence into account. The original scientist would eagerly accept the new evidence, as well as the modification of his earlier hypothesis. More and more scientists would join in the search for evidence, or reliable, reproducible experimental results.
   Eventually, after many, many years of study, having amassed an overwhelming amount of evidence to support it, and in the absence of any compelling evidence refuting it, and with the agreement of the vast majority of working experts in the specific field of study, the hypothesis might be considered a theory.
   So it is with evolution. Although the word theory is used to describe it, the scientific community consider evolution to be fact.

   This does bring us to the question of why, if it is so strongly supported by the evidence, does evolution meet with such scrutiny and doubt. I think a part of the answer to that lies in the nature of the evidence. A perusal of Pharyngula, the blog of evolutionary biologist, and university professor PZ Myers, leads to posts about acoelomorph flatworms, rhabdomeric and ciliary eyes, niobrara chalk, and pharyngeal arches. What are all those things? Idonot have a freaking clue, and quite frankly, not being a student of evolutionary biology, I have not even read those posts. The problem with the evidence supporting evolution, is that it is so damn...scientific. The average guy (or girl) just does not understand it.
   Contrast to that another well supported theory: Newton's Theory of Universal Gravitation. Like evolution, gravity is 'just a theory.' Unlike evolution, every single person on earth has a ton of experience with gravity. When I jump up, I come back down. When I trip over my own feet, I do a face plant on the ground. Although my cat always lands on her feet, it is never on the ceiling. Gravity is a theory no more well supported by evidence, but much more accepted by the general public, simply because we see the effects of gravity all around us, all the time.
   Which brings us to your next point: "there is no proven evidence of man's evolving into anything for thousands of years." Well, yeah, there is. There are evolutionary mechanisms at work in humans, and all living things, all the time. For example, a segment of the Scandinavian population of Europe has developed an innate resistance to AIDS. How? A random, apparently beneficial mutation to the DNA. Those who have it, will pass it on to their progeny. Evolution at work. Can you see it? No, but it is there.
   How do I know? Well, I don't. I said before, I am not a student of evolutionary biology or genetics. So, I have to trust someone who apparently does know. Like, say, someone who has spent their entire life studying the topic. That really is not any different from what we do for most things in our everyday life. When my doctor tells me I have a streptococcal throat infection, I do not ask him to see the actual bacterial culture, because it would not mean anything to me. I take his word for it, because I consider him to be an authority in his field.

   In order to address your next point, and for that matter, the rest of them, I must first take issue with your use of the word 'prove.' Proof is a word that scientists are loath to use. It really does not apply outside the field of mathematics. Any scientist with a gram of ethics admits that scientific principles are never 'proven.' They are always open to new evidence that might cast a new light on older theories, and require some things to be reconsidered, and reworked. That is a basic tenet of the scientific method. Detractorsalways jump on this as an admission of uncertainty, when it really is not.
   The theory of universal gravitation is not 'proven' either. It is open to new evidence that might require it to be re-examined. However, how likely do you think it is that one time, when you jump up, you might not come down? Here is an experiment to try. Flip a coin 100 times. Record the number of times it does not come back down. Try flipping it 1000 times, or 100,000 times. If it comes back down every time, even after 1,000,000 trials, have we 'proven' the theory of gravity? No, it is still a theory. However, if you jump up, you are very confident predicting that you will come back down. Scientists are that confident of predictions they make using the theory of evolution. They have seen such a huge body of evidence in support of it, that, although they will not call it 'proven,' they consider it as close to proven as can be in any scientific discussion.
   That huge body includes a preponderance of evidence supporting the theory that we are descended from animals. Evolutionary scientists have seen so much evidence supporting that conclusion, that they consider it no longer in dispute. It is not 'proven,' but it is so certain, that scientists get bored discussing it. They roll their eyes at people who dispute it for exactly the same reason they roll their eyes at people who still claim the world is flat. You would roll your eyes at someone who claimed the world was flat, would you not? The evidence supporting common descent is so strong that anyone disputing it can only do so based on a complete lack of understanding of the topic. I am not saying people who dispute common descent are stupid, I am just saying they are not evolutionary biologists.

   Next. You say, "There is no proof of the earth's age," and, "carbon dating is an unproven method," as if those two statements have anything to do with each other. They do not. Radio carbon dating is not one of the methods used to estimate the age of the earth.
   While I might not say that carbon dating is unproven, I would say that it has its limits. First, it is only considered accurate for dating things between about 150 and 50,000 years old. Second, it is pretty easy for impurities in a sample to skew the results. However, within these limitations, it is understood to be a very accurate means of determining the age of something.
   Actual methods of datingthe earth vary. As a beginning, we are all familiar with counting tree rings, and we have tree ring evidence that shows that trees have been growing on the earth for over 10,000 years. Examination of Antarctic ice core samples, possible because annual ice layers can be counted the way tree rings are, tells us that the current southern polar ice cap is approximately 160,000 years old. A similar method involves coral. Coral displays very consistent growth patterns both daily, and over the course of a year. You can calculate the age of a coral reef in much the same way as you can a tree, and portions of the Great Barrier Reef in Australia have been calculated to be several million years old. Some say as old as 18 million years.
   The most common method of dating the age of the earth is radiometric examination of rocks. Based on the fact that uranium decays into isotopes of lead at known rates, scientists examining the ratios between the uranium and three different isotopes of lead calculate an approximate age of the earth at 4.5 billion years. That estimate holds up through multiple examinations of the same rock samples by several different, independent laboratories, and across tests done on thousands of different rock samples of both terrestrial and extraterrestrial origin. So, not only is the earth about 4.5 billion years old, so is the rest of the rocky material in our solar system. These findings are not in dispute. At least not by anyone with the understanding of geological science, and radiometric processes, sufficient to speak authoritatively on the matter.
   I am sorry I was not able to provide you with any 'proven facts,' but rest assured that no one, anywhere, has presented any evidence that would call any of these things into dispute. None. As for the appearance of dinosaurs in the Bible... I have read the Bible, and I don't remember any. Of course, I am not a biblical scholar, so I cannot say for sure. I am willing to examine any evidence you might provide.
   And if you were joking, well, you got me.

tags: Skepticism, Evolution