Is Darwins theory of evolution just a theory?

Is Darwin’s theory of evolution just that, a theory?

This is hardly a new topic, but I wanted to stake out my position. A group of parents in Dover, York Co., Pennsylvania have gone to court against the Dover Area School Board, to prevent the teaching of “Intelligent Design” as an alternative to the theory of evolution in their local schools. The school board recently required teachers to read the following statement their students, despite a fairly strong opposition among members of the community:

“Because Darwin’s Theory is a theory, it continues to be tested as new evidence is discovered. The Theory is not a fact. Gaps in the Theory exist for which there is no evidence. A theory is defined as a well-tested explanation that unifies a broad range of observations. Intelligent Design is an explanation of the origin of life that differs from Darwin’s view.”

Up to the last sentence, I have no real objections to the wording of this statement. Their definition of “theory” is informal, yet reasonable, and it corresponds well to the definition given by the careful lexicographers of the Oxford English Dictionary, which I paraphrase here:

theory, n.: A system of ideas or statements held as an explanation of a group of phenomena; a hypothesis that has been established and confirmed by observation or experiment, and is accepted as accounting for the known facts.

Oxford English Dictionary

They are correct to distinguish theory from fact, and have quite reasonably pointed out that evolution—like all scientific theories—continues to be tested by observation. I’m not aware of any specific predictions made by the theory of evolution that are not borne out by fact, but I will not quarrel with the possibility that “gaps [exist] in the theory,” even though such a claim would be much more believable if they gave some concrete examples.

Where it all goes to hell (so to speak) is on the last sentence: “Intelligent Design is an explanation of the origin of life that differs from Darwin’s view.”

The modern theory of evolution is based upon the hypothesis that living systems change by a slow process of random mutation and natural selection. Occasionally, in the normal course of events, small mutations appear in the genetic machinery of a creature; some are harmless, some harmful, and some beneficial, to the extent that the creature’s ability to survive and reproduce are affected by them.

Through the ordinary process of genetic replication, these mutations are transmitted to subsequent generations, and over many generations, an accumulation of such mutations will result in observable variation among otherwise similar creatures. As a theory, evolution provides a simple and practical explanation for both the diversity and the similarity of living organisms.

Insofar as the term “Intelligent Design” has any definition at all, it hangs upon the conceit that certain aspects of the universe—and particularly of living systems—are so complicated that they could only have occurred by means of intentional decisions, and further that these decisions must have been made by an intelligent entity possessing the power to influence the structure of the universe.

In other words, ID proponents claim that the accretion of random changes could not possibly account for life as we now know it, and propose that the simplest reasonable explanation is some unknowable intellect, making all the hard choices. That’s an “explanation of the origin of life” in the same way that “the Devil made me do it” is an “explanation for criminal behaviour.”

I actually don’t object to the content of this final sentence, however (although I do disagree with its premises). My chief complaint is that it has been juxtaposed with the remainder of the paragraph. This adjunction gives the final sentence an unwarranted glamour of relevancy to the remainder of the statement, and as a consequence, the whole paragraph becomes logically disingenuous.

You might think I’m nit-picking, but this is an important point: By adding one sentence to the end of an otherwise-reasonable paragraph, the Dover Area School Board has turned a simple statement about scientific principles into an official endorsement of a fundamentally religious viewpoint.

Maybe the problem will be clearer if we look at a less politically charged example, such as the following:

“Because a ham and cheese sandwich is a sandwich, it varies as new condiments are added. There is no unique way to make a ham and cheese sandwich. Sandwiches exist which contain no ham, and no cheese. A sandwich is defined as a collection of one or more different foodstuffs layered atop a slice of bread. A liver and black olive sandwich is a kind of sandwich that differs from a ham and cheese sandwich.”

See the problem? Nobody would deny that “a liver and black olive sandwich is a kind of sandwich that differs from a ham and cheese sandwich,” but the fact that this statement just happened to focus on liver and black olive sandwiches was no accident—the olive magnate who wrote it (whose brother-in-law happens to own the largest chain of liver packing plants in North America) had a vested personal interest in highlighting this particular kind of sandwich.

Attaching it to a fair and balanced paragraph about the rôle of ham and cheese sandwiches in the Sandwich Pantheon makes it seem merely exemplary—perhaps even accidental. But don’t be fooled!

By analogy, those who wrote the evolution statement for the Dover Area School Board did not cite Intelligent Design simply as an “alternative to evolution,” rather, they did so because they have a vested personal interest in promoting Intelligent Design. Maybe they’re closet Creationists, trying to avoid being lumped in with the Flat Earth Society and other intellectual laughingstocks. I don’t know what their motives are, but if they feel the need to hide them in such a subtle guise, you can rest assured I’m suspicious about them.

Another problem I have with the Dover board’s statement is the unwritten yet strongly-implied use of the word “merely” in the first sentence: “Because Darwin’s Theory is [merely] a theory, etc.” The implication seems to be that theories are just random guesses that somebody makes up while drunk, and that they have no real connexion to reality. I’ll be the first to admit that there are a few theories matching the latter description, but for the most part, scientists do not just come up with this stuff out of thin air.

An idea like the theory of evolution takes untold years of very careful observations and clever insights to develop. New theories are usually not obvious, and are often difficult to believe at first. Once a theory is propounded, it will be tested by innumerable painstaking experiments, conducted by highly skeptical scientists whose entire careers could be made by finding compelling evidence against the theory.

And then some wag comes along and says, “Oh, evolution is just a theory.” It’s as if somebody came up with a faster-than-light starship, and a few years later they’re saying, “Oh, it’s just a way to get from Point A to Point B.” Sure, that’s true, but it’s a really good way to get from Point A to Point B, and one hell of a lot better than anything else we’ve come up with so far. To say it’s “merely a theory” belittles an enormous array of significant contributions to human knowledge that were built around that theory. 

Anyway, it may be stretching the analogy a bit, but I think suggesting Intelligent Design as an alternative to the theory of evolution is a lot like saying, “Well, your faster-than-light starship is pretty neat, but have you considered replacing that solar hydrogen ramjet with a horse-drawn capstan drive? We can’t believe ramjets could possibly work the way you say, but we’re pretty comfortable with horses.”

I was going to talk about how you can convert any finite string of symbols over a fixed alphabet into another finite string of symbols over the same alphabet using a finite sequence of point-mutation operations (i.e., replace one symbol with another, insert a new symbol, or delete an existing symbol), and use that to shoot down the idea that there could be genetic states unreachable from any initial configuration, but this is already getting rather long, so I will leave that for another posting.

Suffice it to say that, for the moment, I think the only way Intelligent Design can argue its way out of that little trap is to argue that there’s something more to a living organism than is expressed in its genes, or the genes of its mitochondria. At that point, we’re back to faith, and that’s where I get off the bus.