The Evolution/Creationism Debate

Lately I've been tracking the changes going on over at the evolution and creationism pages. As someone with a healthy science background, I find the debate between evolutionists and creationists very interesting, as many of the misconceptions people commonly hold about science typically come out of such a discussion.

What is Science?

What is science? This might seem like a fairly silly question...everyone knows what science is, right? I find that there are a few subtleties that can trip people up, especially in a discussion which has such deep rooted meaning for both sides as the evolution vs. creationism debate. Now, as I said above, I'm a science guy, so it shouldn't surprise you that I don't recognize creationism as "science" any more than I recognize astrology or numerology as sciences. Unlike many laypeople on the evolution side of this debate, though, my background allows me to explain concisely what science is in a general sense, and then you can decide for yourself whether creationism is science.

If I had to define science in a single concise statement, here's what I'd say: science is a system of reliably making predictions that is accessible to everyone. That's it. In my mind, this is precisely what separates science from other frameworks of thought such as religion. Of course, there's a bunch of stuff in there about the scientific method and the philosophy of science, but in short, the quickest way to tell if you're dealing with science is to ask yourself if it allows you to make meaningful predictions.

Of course, none of definitions provided here are meant to be complete or exhaustive. Rather, my goal is to capture the relevant factors that apply to the debate.

Scientific Fact

The keystone of all science is the idea of the scientific fact. A scientific fact is an empirically evident observation that is repeatable and reproducible.

Why such a complicated definition? Can't we just agree that a fact is simply a true thing? As it happens, because the concept of facts is the foundation of all science, we need to make sure we nail it down exactly so that the discussion doesn't get slippery, semantically speaking, later on. So we can break it down, piece by piece, to understand what one means when one talks about scientific fact.

Empirical

In this case, empirical means guided by practical experience and not theory. In other words, a scientific fact does not depend in any way on a theory; a scientific fact is invariant with respect to the theoretical context around it. (This, by the way, does not mean that a fact is totally context-independent.)

For example, if I drop a ball I might say that it is a fact that it accelerated towards the ground. Someone might dispute that fact by pointing out that, if I let go of it while it was resting on something, it could not have accelerated towards the ground. So I must express the setup of the ball's physical context before my statement of fact is meaningful; in this case, I must make sure it is well understood that the ball was not resting on something at the time, that I was near the Earth's surface, etc. So, if I'm going to report that I observed a bunch of facts, it is necessary for me to describe the relevant physical context of those facts. This is why every scientific experiment must take great pains to carefully describe the setup.

On the other hand, it is not important to describe any theories of any kind if one wishes only to establish facts. Facts are facts--the theory that happens to be under test in any given experiment has no impact on the existence of a fact. So, facts are empirical; they depend upon practical experience and not theoretical models.

Evident

A scientific fact must be evident. If the procedure that manifests an observation of the fact is carefully executed, the fact should be obvious.

Observed

A scientific fact must be observed. This is an often glossed-over property of facts because in the common parlance, any statement that is generally accepted to be true is often called a statement of fact. This is not so in science, however. A scientific fact refers to a particular event or characteristic of an object that occurred at some point in the past and was witnessed.

This is important for several reasons, but chiefly, this approach enforces traceability of the fact and ensures that it is a statement about something derived from actual experience--a specific instance of reality in action. When speaking informally, one might say, "It is a fact that if I drop this ball it will fall to the ground." Scientifically speaking, this would not be a fact. In order to state a scientific fact, one would instead say, "Last time I dropped this ball, it fell to the ground."

This is a very subtle but important difference, as you'll see later on.

Repeatability and Reproducibility

A scientific fact must be repeatable. That is, a fact must be observable arbitrarily many times under the same conditions.

A scientific fact must also be reproducible. That is, a fact must be observable by anyone who is willing to perform the experiment.

Scientific Theory

A scientific theory is a model, restricted to a well-defined problem domain, based on scientific facts that generates testable predictions.

In short, once we have collected enough facts, we may start to synthesize them into a model that suggests other possible facts to us. (One may guess whether a particular "suggested possible fact" will indeed turn out to be a scientific fact or not. This guess is called a hypothesis, and is tested by performing an experiment.) This "synthesis of facts" is the beginnings of a scientific theory, but it is not quite a theory yet. Before such a model can be called a theory, we must first know the domain of problems to which it applies. For example, I might develop a model that says when I release objects, they accelerate in the direction parallel to my body and towards my feet. But if we performed a series of experiments, we would find that this is only true if I'm standing upright on a massive body such as Earth when I release the ball. Once we test several predictions made by this "proto-theory" we begin to get an idea of where it applies (Earth, the moon, Titan, etc) and where it does not (empty space, or even Earth if I'm standing on my head, etc).

Because a the boundaries of any theory must be well-defined, it is acceptable to restrict the domain as much as possible, even excluding areas in which the theory applies until we have tested those areas and can include them definitively. Naturally, science strives to make theories as general as possible, because the utility of a theory scales up with the size of its problem domain.

"Good" and "Bad" Vs. "Better" and "Worse"

Obviously, a theory that can make useful predictions in a superset of another theory's problem domain is a better theory (presuming its predictions are at least as accurate). Having said that, we come to another common pitfall in understanding science. And that is: while a theory can be "better" or "worse" than another theory, no theory can be "bad" or "good" in and of itself.

A theory cannot be "bad" because, if it has attained theory-hood, that means it makes some kind of useful prediction in some kind of problem domain. No matter how restricted and small that problem domain happens to be, it is quite possible that the predictions of the associated theory are highly useful...and how could that be "bad"? (One could argue that a theory which has the degenerate problem domain of an empty set is a "bad" theory. To this, I would point out that such a theory makes no useful predictions and therefore could not have attained theory-hood in the first place.)

Similarly, a theory cannot be termed "good" in an objective sense. Placing value judgments on scientific theories is nonsensical--if a theory produces useful predictions then people will find it beneficial to some degree or another, but at what point does such benefit cross over into the realm of being "good"? This depends purely on how one defines the term good, which could legitimately vary from person to person based on whether the theory-in-question provides any kind of benefit to that individual. In other words, arguing about whether a theory is "good" or not is a highly subjective discussion that's really more about semantics than it is about science.

It might seem paradoxical, then, that one theory could be "better" or "worse" than another. But, if you think about it for a moment, it should become readily apparent. While one cannot objectively place value judgments upon a single theory, it is possible to objectively compare two theories and deem one better, or more useful, than the other. The main considerations are: (a) which theory makes more accurate predictions? and (b) which theory applies to a larger domain of problems? If one theory's problem domain completely subsumes the other's without sacrificing accuracy, then it is without question the better of the two because it allows for all of the same predictions and more. If the problem domains of two theories overlap in one area but also have areas exclusive to each, then it makes sense to simply keep both of them around. In some areas of the overlap, one of the two might produce more accurate predictions; in that case, that theory is the better one for those areas.

A Scientific Approach to the Debate

First, it's necessary to understand the position of each side in the evolution/creationism debate; what does each side want?

In this case, the controversy is usually over whether creationism should be taught alongside evolution in public school science classrooms. The evolutionists say no, the creationists say yes. So how can we apply this understanding of science, scientific fact, and scientific theory to this debate in order to answer such a question?

Is Creationism Science?

If the creationist side of the argument wishes to teach creationism in science classes, it makes sense to determine whether creationism is science or not. Creationists claim that creationism is as much a scientific theory as the theory of evolution. Determining whether this is so turns out to be fairly straightforward. Is creationism a predictive model, based on facts, that is restricted to a well-defined problem domain?

I would argue that it is not. I feel I could attack this question on many fronts, but remember that creationism must only fail one of the characteristics of theory-hood in order to be disqualified from being considered a scientific theory worthy of being taught in science classes. So, my primary argument is that creationism is not predictive in any way, shape, or form. Creationism is indeed a complete explanation of how life came to be as it currently is, and one may argue about whether this explanation is fact-based or works within a well-defined problem domain, but regardless of how those arguments turn out, creationism still provides only an explanation, but no testable predictions at all.

Is Evolution Science?

One of the most commonly mounted arguments by creationists is that creationism is as scientific as evolution, and since evolution is taught in science classes, then creationism ought to be taught there as well. Conversely, any reason that would exclude creationism from being taught in science classes could also just as easily be applied to evolution. In other words, it's not enough to merely show that creationism isn't science, we must also show that evolution is.

To answer this question, it is first necessary to differentiate between the fact of evolution and the theory. So, I will refer to the fact of evolution simply as evolution from here on out, and I will refer to the theory of evolution as, simply, the theory of evolution or Darwinism.

Is evolution a scientific fact? Can organisms change over generations in response to an environmental stress because genetic variations permit some to live while dooming others to die?

Sometimes, the genetic variety present in a given population does not allow for the survival of some of the organisms for a particular environmental stress factor. In this case, the entire pool of organisms die out. In other cases, most all of the organisms happen to already share a characteristic that is suited to deal with the new stress, in which case the population as a whole barely notices the new stress factor. In both of these cases, no (or not much) evolution occurs because the stress factor does not differentiate between characteristics of individuals within the population; either all of the organisms live or all of the organisms die.

There are situations, however, in which a stress does affect some members of the population differently than others. In this case, if some of the organisms enjoy characteristics that allow them to reproduce while others do not, and if those characteristics can be passed to offspring (i.e., they're determined by the genetics of the organism), then evolution has occurred. Note that I do not say that evolution does occur, or that it will occur, but rather that it has been observed to occur. With a bacterial culture, a few drops of the right toxin, and a Petri dish, anyone may observe the scientific fact that evolution occurs. Anyone familiar with the ever-increasing potency of antibiotics understands that the drugs of yesterday are no longer effective because evolution has occurred.

What about the theory of evolution? Is this a veritable scientific theory? Has it allowed us to make testable, accurate predictions within a specific, well-defined problem domain? Indeed it does. To see that this is true, one may perform an experiment using the aforementioned bacterial culture, toxin, and Petri dish. You could theorize that descendants of the initial culture will become progressively more resistant to a particular toxin or antibiotic. The fact that predictions that follow from the theory of evolution such as this have been tested and shown to be accurate time and time again spells out the answer: the theory of evolution is indeed a scientific theory. It's also important to note that this example is a degenerate case; the theory of evolution has made all sorts of predictions about all kinds of things. Some of these predictions that pertain to a particular area of the problem domain have always been observed to be true, allowing us to add to our body of scientific facts. Other predictions have allowed us to definitively exclude other areas of the problem domain. Of course, there are still areas of the problem domain that are not black or white, but grey--in these situations we are still testing the predictions to see if the area of the problem domain under study can be addressed by the theory.

Conclusion

Based on a simple understanding of what science is about and careful definition of terms, it is clear that creationism is not science while both evolution and evolution theory are. At this point in the discussion, nothing more is needed to determine what type of class ought to address each; creationism should be presented in religion classes and evolution can be addressed in science classes. Teaching creationism in a science class makes as little sense as teaching evolution in a religion class (so it is with some irony that many creationists argue that evolution is as faith-based as creationism--I hardly think most of them would allow the teaching of evolution in religion classrooms).

Common Attacks on Evolution

In the attempt to frame creationism as a form of science to be taught alongside evolution in public schools, creationists have put forth several specious arguments. This section addresses several.

The Bible as Absolute Truth

Creationists almost universally take issue with evolution because it contradicts the Bible's account of how life on Earth came to be. Some creationists claim that evolution simply cannot be a valid scientific theory because the Bible is a sacrosanct true account.

The problem with the Bible-as-absolute-truth argument is that it implies there is no human interpretation whatsoever. Even if we assume that the Bible is the divine word, it is obviously true that different interpretations of the book exist. Often the very people that put forth this argument attend Bible study classes on a regular basis, the purpose of which is to puzzle out exactly the underlying meaning of what the book says. So, even if we assume the Bible is absolutely true, no one person's reading of it can be taken as absolutely true. To put it a different way: no point of view derived from a reading of the Bible can be accepted as the truth, even if we assume the Bible itself are the words of an all-knowing being. Even though the words themselves may be the Truth, the interpretation of those words is carried out by fallible humans.

Evolution is not the first time the Bible has been misread by believers. A misreading of the Bible by the Catholic church led to the imprisonment and persecution of Galileo, which now even the church itself acknowledges was a mistake.

When discussing this point with creationist friends, they often question whether this argument makes sense. "Why," they ask, "would god provide us something inscrutable? This doesn't make sense, so it cannot be right." And yet it is clearly true, as arguments over Biblical interpretation occur even within the most fundamentalist creationist groups. All I can say is: god works in mysterious ways.

Evolution is "Just a Theory"

This argument is very similar to the Bible-as-absolute-truth argument, except instead of promoting the creationist point of view, it attempts to diminish the evolutionist point of view by placing a negative value judgement on scientific theory in general. After all, a theory is not absolute truth, so why should one "believe" in it?

This is actually a valid question. Why should anyone hold a theory as a belief? I contend no one should hold a theory as a belief. Furthermore, believing in a theory in the same way one believes in a religion is bad science!

There is a difference between holding an idea and holding a belief. An idea is based on understanding, and as one's understanding changes, so do one's ideas. A belief is static; a belief is held in spite of changes in one's understanding--the expectation of a belief is that, given the necessary investment of time and effort to form understanding, one would arrive at the belief. The ability to hold both beliefs and ideas is necessary; otherwise, no one could learn from the experience of others without a large investment of time and energy in forming understanding. Often, if a belief accords with our other beliefs and ideas, it is simply more expedient and practical to accept it on faith.

But the realm of beliefs and ideas are quite different. A belief is useful in terms of forming expectations without understanding, but it relies upon someone, at some point, having understood a thing. Science is in the business of understanding things which have not yet been understood by anyone. So, all scientific research places little value on belief, as it simply does not apply to the problem domain under study.

Recognizing this has a profound impact on how one understands scientific theories. No scientist believes in a theory in the sense of believing in a religion or believing in a fact. If Einstein had believed in Newton's theories of matter on the same level as the facts that seemed to contradict them, it would have been impossible to make progress towards a new theory of relativity. In science, a theory is recognized by scientists for what it is: a predictive model. Whether or not the internals of a model form a direct correspondence with underlying reality is unimportant to a scientist, and furthermore, this kind of correspondence is not, and does not have to be, assumed for the model to be useful. After Einstein's theory of relativity, for instance, we do not discard Newton's theories even though in a sense they are "wrong". As addressed previously, this is because it is nonsensical to use absolute terms like "bad," "good," "right," and "wrong" when discussing theories. A model, which is by definition an approximation of reality, cannot be any of these things.

In the end, evolution theory is a bona fide theory because it still meets all of the criteria for any other scientific theory. To disparage evolution because it is "just a theory," and therefore not worthy of belief, is to similarly disparage all scientific theories (certainly no one would say that gravitation theory is "just a theory"). To the contrary, to admit that evolution theory is indeed a scientific theory works against the creationist argument because it places evolution theory smack dab in the middle of public school science classes. Also, it implies that creationism is not "just a theory" (why would a creationist disparage his own stated belief?), and therefore should not be taught in science class.

Micro-Evolution Does Not Imply Macro-Evolution

Oftentimes in a debate with a creationist, after I establish the difference between the fact of evolution and the theory of evolution, the creationist is forced to admit that, yes, the fact of evolution is indeed indisputable scientific fact. At this point the debate takes a turn--the creationist has now allowed that evolution occurs, but not the kind of evolution proposed by evolution theory that conflicts with his religious beliefs, usually based upon his interpretation of the Bible. Thus it becomes necessary to split evolution into two: one kind that accounts for evolution we can observe directly and does not conflict with religious belief, and another kind that we have not observed directly and does conflict with religious belief. As this religious belief usually stems from interpretation of the Bible, the evolution is split into micro-evolution and macro-evolution. At this point in the debate the creationist will state that he accepts micro-evolution, but not macro-evolution.

There is a problem, however, with defining this split in terms of what does and does not conflict with religious belief--it is completely arbitrary. This argument is specifically against evolution theory; it admits the fact of evolution but claims that the theory based upon those facts is flawed because it has not been observed--in short, the theory should not be accepted because it is not fact itself.

The motivation for this split arises from an interpretation of the Bible that states no species can arise from another. It is important to note that the very definitions of the terms micro-evolution and macro-evolution used by creationists is rooted in Biblical interpretation, based upon what must be accepted as indisputable fact and not logic, reason, or scientific research of any kind. In any case, at this point everyone agrees that evolution within a species, so-called micro-evolution, exists. What about evolution that results in a new species?

First, how is species defined? If two organisms can produce fertile progeny, they are of the same species. My creationist opponent, on more than one occasion, has argued at this point that it is simply illogical to expect that one species could arise from another. This argument goes: let's assume two organisms produced a child of a different species. This new species could not propagate unless two other organisms somewhere also happened to produce a child of this new species, and of the opposite sex. The idea that two members of a new species would just happen to come into being at the same time strains credulity. Often accompanying this argument is a thought experiment that illustrates the absurdity of such an event: imagine that a whale were to somehow produce a bear. Even if we assume that this is possible, what are the chances that some other whale would also produce another bear so that this new species called bear could continue its existence beyond a single generation?

This is of course a straw man argument. Evolution theory does not require that a new species be introduced in a single generation. Rather, the theory contends that small genetic changes from one generation to the next accumulate over time, eventually giving rise to a new species. At every point, organisms from any given generation could produce fertile offspring with members of several previous and several subsequent generations. But, if you go far enough into the past or the future, at some point the accumulation of genetic differences would prevent fertile offspring, much like a horse and a donkey produce the infertile mule.

To address the micro- vs. macro-evolution argument as a whole can be done just as easily. The taxonomic categorization of organisms is a man-made construct. It is people that decided the criteria that separate animals into kingdom, phylum, genus, species, etc. How is it reasonable to presume that there exists some mechanism inside cells that prevents genetic mutations on the basis of taxonomies that are arbitrarily defined by people? Once one admits that evolution occurs within a species, it naturally follows that mutations could conceivably accumulate to any degree without regard for species boundaries.

Discounting macro-evolution while accepting micro-evolution is tantamount to the belief that, inside every cell, there exists a mechanism which prevents mutations that would give rise to offspring if that offspring could not produce fertile progeny with not just its parents' generation, but its grandparents', great-grandparents', etc, all the way back to the beginning of life itself. Scientific research refutes this. In fact, all scientific research on genetics supports the exact opposite conclusion--that no such mechanism exists.

Evolution Theory Depicts a Past that Contradicts the Second Law of Thermodynamics

In just about every discussion of evolution with creationists, the Second Law of Thermodynamics almost always comes up. I have heard this argument stated in many forms, but here are the two most popular:

Would you expect a hurricane to blow through a junkyard and build a car?
If you put all of the components of a watch into a bag and shook it, how long would you expect to have to shake the bag before the parts assembled themselves into a watch?