Walter M. Fitch, a pioneer in the study of molecular evolution, has written this cogent overview of why creationism fails with respect to all the fundamentals of scientific inquiry. He explains the basics of logic and rhetoric at the heart of scientific thinking, shows what a logical syllogism is, and tells how one can detect that an argument is logically fallacious, and therefore invalid, or even duplicitous. Fitch takes his readers through the arguments used by creationists to question the science of evolution. He clearly delineates the fallacies in logic that characterize creationist thinking, and explores the basic statistics that creationists tend to ignore, including elementary genetics, the age of the Earth, and fossil dating. His book gives readers the tools they need for detecting and disassembling the ideas most frequently repeated by creationists.
The Three Failures of Creationism Logic, Rhetoric, and Science
Logic, Logical Fallacies, and Rhetoric
In writing this book, it was my intention that it be for people who have no irrevocable position on at least some of the differences of opinion between creationists and evolutionists, but who would like a view of those arguments that is relatively fair. That I have not totally accomplished, as I am clearly an evolutionist and believe in the naturalist (materialist) view, whereas creationists do not. And therein lies the difference. I hope to have produced in this book a clear differentiation of the reasons for what evolutionists believe and what creationists believe, written at a level that intelligent high school seniors or college freshmen or sophomores can readily understand without their having taken any biology or theology courses. I am targeting that group because, in my opinion, it is the failure of scientists to present clearly what they do and why that has caused so many problems in our schools and courts. I welcome criticism from all parties, especially where I have done injustice to any view, and if this book survives to a second edition, I will correct those errors. I have included a short glossary to aid the reader in understanding some of the terms used in this book.
Not all biologists will necessarily agree with 100 percent of what I have to say. Nevertheless, I believe that the vast majority of evolutionists will agree with almost everything evolutionary that I present. Similarly, not all creationists will agree among themselves that my representation of their view is correct or complete, although the degree to which creationists agree among themselves may often be much less so. The point is that too often one side denounces the other for an opinion that has been given by a member of the opposing camp, even though the opinion being denounced has become rare and unrepresentative of current creationist or evolutionary thought, as the case may be.
Generalities are not intended to be 100 percent applicable, but if something is true 99 percent of the time, that something accordingly is important and frequently not refutable by describing a single exception. This is an example of the straw man fallacy, which takes an unrepresentative view of one's opponents and attacks that view, even though it is already recognized as unsupportable in its extreme form by those same opponents.
The principal goal is to establish what science is and how biological evolution is a scientific study, no matter what errors may be present at our current level of understanding of evolution. This is true even if Darwinian evolution itself should be proven wrong. In contrast, creationism, intelligent design, and irreducible complexity are not scientific, even if their conclusions (such as that God made the universe in six literal days about six thousand years ago) were shown to be all correct. It is my hope to represent the creationist viewpoints as those of people with different criteria for resolving important questions. Nevertheless, I hope that if people can understand what evolutionists do and how and why, they will understand that creationism is rarely if ever scientific. Biological evolution is almost always scientific, and thus the reader will understand why evolutionists oppose the teaching of this theological view as part of any science course.
I try to present both sides fairly in describing what strict creationists believe. In evaluating those beliefs, however, I shall rigorously apply scientific and theological methods as appropriate. For example, a creationist may say he believes that the Bible is the word of God and therefore cannot be wrong, that the Bible says the world was created in six days, and that he therefore he believes that the world was created in six days. His logical argument in itself is quite valid (and we will elaborate further on chains of logic later in this chapter). Consider the following syllogisms. (A syllogism is a form of deductive reasoning consisting of a major premise, a minor premise, and a conclusion.)
Premise 1: The Bible (Old and New Testaments) is the Word of God.
Premise 2: The Word of God cannot be wrong.
Conclusion 1: The Bible cannot be wrong.
Conclusion 1: The Bible cannot be wrong.
Premise 3: The Bible says the world was created in six days.
Conclusion 2: The world was created in six days.
Note that Conclusion 1 is also the first premise of the second syllogism. But both of these premises are theo-logical, not materio-logical. They are theo-logical because the premises themselves are about God and God's Bible. This difference is crucial in that the starting premises of the creationist are not the same as those of the evolutionist. Hence differing conclusions should be expected, even though our rules of logic are (or certainly should be) identical. The problem of logic is sufficiently important that the majority of this chapter is devoted to logic for those who might enjoy a minimal refresher course on the subject of how we decide which conclusions are logically admissible and which are not.
Critics of evolution often claim that it cannot be correct because it occurs via random genetic mutations, and random processes cannot create order. It is true that mutations are random, because they are not directed by a force that guarantees that, given the ancestral form, the nature of the character can be predicted. But mutations are only half the story. Environmental pressures are directive, and this leads to what is termed natural selection. Biological evolution is the study of the origins of the diverse nature of living things. It was inspired greatly by Charles Darwin, who, in 1859, proposed a theory for the origin and diversity of the living world. It was, and still is, called natural selection, and it postulated that sources of variation (later to be called mutations) occurred in nature. Some variants/mutants were harmful and were weeded out. A much smaller number of mutants were beneficial and spread through the population. The mechanism of evolution was that more offspring were produced than the habitat could support, and thus many members of a population would not produce successful, reproductively viable offspring. Those that did, did so because of the favorable effects of the useful mutations. Note that the creation of the mutations is a random process, but selection of mutants with a beneficial effect is directional. It was natural to portray the history of life as a genealogy in a branching tree that showed who came from whom and approximately when.
Many devout Christians (and other religious people) find no conflict at all between natural selection and their religion. Evolution, they assert, is simply "the way that God did it." Nevertheless, many evolutionists' statements directly contradict a literal interpretation of some of the statements given in the initial chapters of the book of Genesis. For those who can interpret Genesis in a somewhat moralistic, figurative, poetic, or metaphorical rather than a literal fashion, there is no problem. But many people, including "young-Earth" creationists, cannot accept this. Thus, although most creationists are Christian, most Christians are not creationist in the narrow, literalist sense used here. But they could well be creationist in a broader sense-believing, for example, that God started the universe but may subsequently have left it alone to evolve according to His rules. I necessarily differ only from the strict creationists-the literalists.
The controversy between creationists and evolutionists often involves logical failures. For that reason, we begin with a section on logical reasoning and its limitations. Logical failures will continue to be noted.
Logic is the study of the meaning of words and the inferences that are and are not allowable, given some data or reasoning. Rhetoric, on the other hand, although it considers the meaning of words and logic, is not so much interested in what conclusions are true as in what the persuasive effect of the words and gestures may be on you-the reader or listener. The object of rhetorical material is to convince you of something, whether true or not. ("Buy my product," "My client is innocent," "My religion is the only true religion," etc.) Logic will be considered first, then rhetoric.
The study of logic is quite ancient (Socrates, 469-399 B.C.), but today logic is dominated by truth tables. A truth table is a set of rows and columns showing true/false values for logical propositions and their components. The true/false values are usually shown, in Boolean algebra style, as "1" for true and "0" for false. Perhaps, for an introduction, it is easier to learn a little about syllogisms. A syllogism is an argument. Any one argument is a collection of three statements (sometimes more) of which the first two statements are called the premises (assumptions or givens; we restrict ourselves to three-statement arguments) and the third statement is the "therefore," or "conclusion." The process is of the following form:
Premise 1: If Socrates was a man, and,
Premise 2: If all men are mortal,
Conclusion: Then Socrates was mortal.
The first two statements are the assumptions being made, and, if they are true, the conclusion in the third line, correctly formed, must also be valid and true. The three lines can be considered more generally as:
Premise 1: A (Socrates) then B (man). OR If A is true, then B is true.
Premise 2: If B (man) then C (mortal). If B is true, then C is true.
Conclusion: If A (Socrates) then C (mortal). If A is true, then C is true.
You will be challenged later to transform an argument into syllogistic form to see if the argument is valid. It is not as easy as one might think. To aid you in achieving success in that effort, some valuable bits of knowledge are presented.
Note that every ordinary syllogism has exactly three different terms or statements: A, B, and C. Each term is used exactly twice. Term A is the subject of premise 1, and B is its predicate or result. B in turn is the subject of premise 2, with C as the predicate. The conclusion eliminates term B, and jumps directly from subject A to predicate C. The order of the two premises is not critical, but the flow of meaning is more natural, and the argument is easier to understand, if the term that occurs in both remises (B in this example) is the predicate of the first premise and the subject of the second. Thus:
Premise 1: Socrates was a man.
Premise 2: All men are mortal.
Conclusion: Therefore, Socrates was mortal.
Or: A implies B; B implies C; therefore, A implies C (conclusion). There are many forms of errors in the use of syllogisms, and some of the more common errors are examined at the end of this section.
B. Deduction versus Induction
If one sees that whenever an event happens it is always followed by the same second event, one may come to believe that the first event causes the second one. For example, "Every time I push this button, the doorbell rings. Therefore the pushing of the button is the cause of the doorbell ringing." This is inductive logic. One infers a general rule on the basis of a limited (but generally large) number of observations. However, there is nothing about an induction that guarantees that it will be a correct conclusion. For example, using precisely the same logic, one gets "Every morning just before dawn the cock crows and then the sun rises. Therefore, the cock's crowing causes the sun to rise."
Alternatively, one may conclude (deduce) a particular thing from a general rule. For example, "Dogs eat meat, so I deduce that my Fido eats meat, too." The understood but unstated premise is that Fido is a dog.
Premise 1: Fido is a dog.
Premise 2: Dogs eat meat.
Conclusion: Fido eats meat.
The conclusion of a valid deduction must be true if the premises are true, whereas an induction may be correct but is not proven. The conclusion of a valid deduction is usually of narrower meaning but true, whereas an induction is usually of broader meaning but unproven (although perhaps likely to be true).
The two most commonly used logical forms are deduction and induction. Consider now a series of items that are either logical errors or rhetorical devices designed to convince you, the reader or listener, of something. You need not memorize the names of all these logically related processes, but just recognize them when they occur. It is good practice, if what you are reading feels slippery, to try to find out why you feel that way. You will frequently discover malpractice in word usage. Several such abuses are illustrated here. Writers rarely provide you with a syllogism, or even a partial one, so you must figure it all out for yourself.
C. Analogical Reasoning
Analogical reasoning is the process of making your logic, in a difficult case, exactly like your logic in another case that the listener will readily understand. The point is generally to make the understanding of your logic easier. For example, "If it is not immoral for tigers to eat humans, then it is not immoral for humans to eat humans." The analogical form changes only one word here and invites you, should you believe the first proposition, to accept the second statement as logically equivalent. Most of us would disavow the conclusion, illustrating that analogy does not lead to something having been proved. Its value lies in making it easier to understand the meaning or content of an argument. Darwin said in The Origin of Species, "Analogy may be a deceitful guide" (1859, pp. 454-55). Nevertheless, Darwin's first chapter is a long list of analogies arguing that if natural variation is available for the breeder of organisms, variation must be present for natural selection to act upon as well.
Analogies can be humorous, as in, "If practice makes perfect, then mal-practice makes mal-perfect." This clearly demonstrates that analogies may make an argument clearer but cannot provide support for an argument.
D. Logical Fallacies
1. Begging the question (circularity): assuming the conclusion you wish to reach.
A circular argument does not advance our knowledge beyond what was already known or assumed in the premises. That is, the argument being presented begs us to ask the question, What is the support for the premises? Or, What do the premises have to do with the conclusion? Consider the following syllogism:
Premise 1: Complex things can be produced only by a designer.
Premise 2: The human eye is a complex thing.
Conclusion: The eye must have been designed.
Are we sure of the first premise? Is it really true that the only way a complex thing can come into being is by the work of a conscious designer?
Or consider how begging the question may be used in political speech:
Premise 1: Smith is a good family man.
Premise 2: Smith was a great football player.
Conclusion: Smith will make a good mayor.
We must ask what the premises have to do with the conclusion. Unless you feel that being a good family man or a great football player somehow builds your character or prepares you for political office, the premises have nothing to do with the conclusion.
2. The equivocation fallacy (also called a category error): using a word with two different meanings in the same argument.
Examples of the equivocation fallacy are given below. A particularly obvious example is the following. First read down the left half of the syllogism to get the silly conclusion that is clearly wrong.
Premise 1: I am a nobody. I am a person of no importance.
Premise 2: Nobody is perfect. There is no individual that is perfect.
Conclusion: I am perfect. (No logical conclusion possible.)
Now read the syllogism again utilizing the phrasings on the right for the word nobody. This shows how changing the meaning of the term nobody between premises 1 and 2 renders the conclusion silly, although the syllogism on the left side is formally valid.
The usage of this equivocation fallacy is the basis of the creationist's rather insidious declaration that evolution is not a fact. One meaning of the word theory, found in ordinary, everyday usage, is that of a guess. Creationists often say in a disparaging tone that evolution is only a theory, meaning that it is only a guess and not a fact. But when a scientist uses the term theory, the scientist means a well-supported explanation uniquely consistent with many thousands of observations. Consider, for example, Newton's theory of motion, Copernicus's heliocentric theory (that the Earth rotates around the sun), Einstein's theory of relativity, or atomic theory.
The creationist's syllogism goes like this:
Premise 1: Evolution is a theory.
Premise 2: A theory is only a guess.
Conclusion: Therefore the theory of evolution is only a guess (and thus is not a fact).
This argument is invalid because it uses different meanings of the word theory. Its illogical result arises from changing the meaning of the word theory between premise 1 ("a well-substantiated scientific truth") and premise 2 ("a guess"). This has also been called the four-term fallacy because of the two different meanings of theory. The correct syllogism is:
Premise 1: Evolution is a theory.
Premise 2: A theory is a well-supported explanation of many observations.
Conclusion: Therefore, evolution is a well-supported explanation of many observations.
This form of the argument is valid and the premises are true, so the conclusion is true. It is puzzling that creationists continue to assert that evolution is "only a guess."
A third instructive example of the equivocation fallacy is the following:
Premise 1: Humans are a species.
Premise 2: A species is a mental construct.
Conclusion: Humans are a mental construct.
The concept of a species is a mental construct, a creation of the human mind, but that is different from human beings being a species. To make a valid argument, the statements should be as follows:
Premise 1: Humans are interfertile with other humans. (That is, they can interbreed.)
Premise 2: A group of interfertile individuals is termed a species.
Conclusion: Humans are a group called a species.
3. The excluded-middle fallacy: assuming that only two alternative explanations exist, black or white. (E.g.: if Darwinism is false, then Genesis must be true.) There is no allowance for a gray or intermediate theory. This is a very important fallacy in the discussion between scientists and creationists. Creationists often construct a world with only two arguable views: creationism, and materialism/naturalism. There is no recognition that more than one version of creationism exists, such as "young-Earth" versus "old-Earth" creationists. Similarly, there is no recognition that more than one version of naturalism exists, such as Lamarckism and Darwinian evolution. This produces a situation in which there are, seemingly, only two contending theories, one of which then must be false and the other must be true. Such circumstances are wonderful but rarely occur in nature, because by proving that one of the contenders is wrong (the evolutionist position), one appears to prove that the other contender is necessarily right (the creationist position). Unfortunately, this argument has a major logical flaw. That flaw is that one is not allowed, arbitrarily, to omit some explanations, or to tie several of them together to get a single entity, in order to reduce the logical system down to a maximum of only two components.
For example, how can the synthesizing machinery obtain the correct sequence of amino acids in a protein? The creationists have their choice: model 1 (God does it); and model 2, a random model for which they can calculate probabilities. Model 2 is the creationist view of what they think evolutionists believe. The creationists make the calculations and rightly reject these random models. Having rejected model 2, they then infer that the creationist model, model 1, must be right. But the inference requires that there be no third model, random or not. In fact there are an infinite number of possible different models. The conclusion depends upon there being no other random models, including a model 3, which is discussed later on (see chapter 3, section B). More than two possible models are conceivable. Thus the creationist argument is already a failure because it is limited to only two possible models. But it gets worse. The evolutionist argument for model 3 has a very high probability of forming the whole protein without error.
4. The genetic fallacy: arguing against an idea on the basis of the proponent's personal character. An example is: "That man is a natural born idiot. How could any self-respecting human vote for his proposal?" [See ad hominem]
5. The naturalistic fallacy: asserting what ought to be true on the basis of what appears to be true. A disquieting example of this fallacy: Some animals eat their young; therefore it would be OK if humans were to eat theirs. This can be stated as a syllogism as follows:
Premise 1: It is acceptable for humans to do what some animals do.
Premise 2: Some animals eat their young.
Conclusion: Therefore, it is acceptable for humans to eat their young.
Premise 1 is disquieting but not necessarily in itself false. Premise 2 is true. The conclusion appears to be true, so the argument is valid. But the argument is not morally acceptable. In the early nineteenth century, the social Darwinists (see the discussion in chapter 2, section B) accepted all this and tried to sterilize mentally disabled people and deny them schooling and welfare etc. on the grounds that the intended recipients were inferior, by nature, and so could not benefit from education. Logic fails us here, but only because ethics and morality are not considered. Logical deductive reasoning can tell us when certain facts are true in terms of a "truth table," but it does not prescribe how those facts should be used. The conclusions drawn from a logical, abstract evaluation may be unacceptable in moral terms or irrelevant to our daily lives (e.g., an imaginary situation). The term naturalistic fallacy was originally defined (by G. E. Moore) somewhat differently from how the current popular definition describes it. The naturalistic fallacy is summarized more frequently by saying that we must not assume an "ought" from an "is." As Albert Einstein wrote, "For the scientific method can teach us nothing beyond how facts are related to, and conditioned by each other.... knowledge of what is does not open the door directly to what should be" (1954, pp. 41-49).
The Italian cardinal Caesar Baronius (quoted by Galileo in his letters) summed up the separation of ethical philosophy from scientific study in 1598 with a wise remark; "The Bible was written to tell us how to go to heaven, not how the heavens go." In the Bible (Luke 20:24-25), a commission of hostile priests challenges Jesus on the issue of authority, asking him whether it is lawful for a believer to pay taxes to a secular authority such as Caesar. Jesus's response is:
"Shew me a penny. Whose image and superscription hath it?" They answered and said, Caesar's. And he said unto them, "Render therefore unto Caesar the things which are Caesar's, and unto God the things which be God's."
We could do worse than to consider ethics and morality to be God's domain, and natural science to be Caesar's.
6. The non sequitur (Latin for "does not follow") fallacy: asserting that a conclusion follows from the preceding material when it in fact does not. For example: "That critical reviewers advance scientific arguments against intelligent design (whether successfully or not) shows that intelligent design is indeed falsifiable" (Behe 2000). To see the incorrectness of the argument, replace the words intelligent design in the syllogism below with the word God, which leads to the conclusion that God is falsifiable. All fallacies are, in one way or another, non sequiturs.
The argument, expressed as a syllogism, is as follows:
Premise 1: Intelligent design has been argued against by scientists.
Premise 2: If scientists can argue against (or for) intelligent design, it is falsifiable.
Conclusion: Therefore, intelligent design is falsifiable.
To be considered scientific, a theory must be falisifiable-that is, you should be able to prove the theory false if a particular fact is observed; otherwise, you have no means of testing the theory by experiment. In the syllogism above, the argument is valid in that the conclusion would be true if the premises were true (Tymoczko and Henle 2000). It is not clear whether the conclusion is true or not. If the conclusion was true, intelligent design could be regarded as scientific, thereby destroying a barrier between evolution on the one hand and creationist areas of knowledge, science, and theology on the other.
7. The rationalistic fallacy: believing that rational arguments will persuade-or, the assumption that human beings will govern their affairs on a purely rational basis by using only logical trains of reasoning. This is a common error, especially among professors; this book may be an excellent example of it! Rational arguments may not persuade if they are difficult to follow or if they challenge long-held and cherished beliefs.
8. Reductio ad absurdum (Latin for "reduced to an absurdity"): reducing an argument to the point of making it appear absurd. Reductio ad absurdum makes use of the law of non-contradiction, which says that a particular statement "A" cannot be both false and true at the same time. Of course, the demonstration of absurdity may rely on a very extreme example of the principle being discussed-so extreme that it is an unfair distortion of the statement given. (See fallacy 9, "Straw man," below.) The wording of the statement is very important, particularly when you use statements like "A is always true" or "B can never occur." A single counterexample can show your position to be absurd. Mark Twain made use of the reductio ad absurdum principle when he wrote that many years ago the Mississippi River was "upwards of one million three hundred thousand miles long." (See chapter 2, section E: "Mark Twain and Science." ) Twain is illustrating the absurdity of assuming that the rate at which the Mississippi River is seen to shorten today has remained constant over millions of years.
9. Straw man: representing an opponent's view in a form so extreme that it is absurd. It suggests that your opponent's logic must be bad when the only thing that is proven is that the argument does not hold in the extreme. For example, your opponent gets his answer by dividing by a very small number. You then declare him wrong because, if you divide by zero, which is very small indeed, the answer is undefined. (See fallacy 8, "Reductio ad absurdum," above.) Demonstrating a contradiction in an argument is valid, but not if you distort the argument into a case it was never intended to cover.
10. The tautological fallacy: formulating a conclusion that is true for whatever set of values (true or false) are entered into our table. The terms are defined in such a way that the conclusion cannot be disproved. Examples of tautologies are "the law of the excluded middle" (A or not-A), "de Morgan's law" (if not both A and B, then either not-A or not-B), and "proof by cases" (if at least one of A or B is true, and each implies C, then C is also true). Tautologies are not always fallacious. The tautological fallacy occurs when the conclusion is already contained in the premises-perhaps using slightly different words. The logical argument does not advance us beyond what is already known or assumed.
11. Miscellaneous fallacies. Either or both premise lines may not be true, and even the conclusion line may not be true. If the first two premise lines are true, then the conclusion line should be true and will be as long as the argument is valid. For example, recall the syllogism at the beginning of section B, "Deduction versus Induction," above:
Premise 1: Fido is a dog.
Premise 2: Dogs eat meat.
Conclusion: Fido eats meat.
This syllogism is sound. But what of the case where the third line instead reads "Bears eat meat"?
Premise 1: Fido is a dog.
Premise 2: Dogs eat meat.
Conclusion: Bears eat meat.
The argument is not valid even though the conclusion is true. The third line introduces a forbidden fourth term ("bears"), and hence this case is also called the four-term fallacy. This represents an interesting case in that both premises and the conclusion ("Bears eat meat") are true even though the logic-the argument-is not valid. Although the formula is true in terms of logic, it was just a coincidence that bears actually do eat meat; it didn't necessarily follow from the premises. To see that the conclusion does not actually flow from the premises, consider another syllogism with the four-term fallacy:
Premise 1: Polly is a bird.
Premise 2: Birds have feathers.
Conclusion: Bears have feathers.
The logical structure is similar, but in this case you can see that the conclusion is absurd.
E. Rhetorical Devices
Rhetorical devices use various phrases and tones for their effect, with or without regard to logic. "What is the authority for ... ?" is a rhetorical question that implies that, after considerable search, no such authority will be found. All of the fallacies, if they are used despite the user's knowing they are fallacies, are then rhetorical devices. Note the famous phrase "That's a rhetorical question," meaning that you aren't supposed to answer the question, which was posed only for effect. Loaded words are another, and very common, rhetorical device.
1. Ad hominem: attacking the speaker rather than the speaker's argument. It is rather in the spirit of "If you have no good arguments on the basis of the facts, then you should: (1) cause confusion; (2) shout louder; (3) assert your opponent's ignorance of the issue; (4) accuse her of unethical or immoral acts; (5) ridicule your opponent; and so forth. Some recent examples include the following:
a. The astronomer Fred Hoyle has hypothesized that life may not originally have begun on Earth, but begun somewhere else and then migrated to our planet (by various interesting ways). Daniel Dennett observes, in his book Darwin's Dangerous Idea (1995, pp. 314, 318), that skeptics sometimes refer to this idea as "Hoyle's Howler" as a way of insulting Hoyle by implying that he is stupid.
b. "The fact that a distinguished philosopher overlooks simple logical problems that are easily seen by chemists suggest that a sabbatical visit to a biochemistry laboratory might be in order" (Behe 1996, p. 221; Behe is a creationist). This sarcastic remark is also insulting.
c. "I have encountered this blunder so often in public debates that I have given it a nickname: 'Berra's Blunder' " (Johnson 1997, p. 63). This is in the same category as the howler. Phillip Johnson was referring here to Tim Berra's use of the changing automobile design in the Corvette sports car to illustrate the concept of "descent with modification." (See chapter 2, section G.1, "Automobile evolution.")
d. "... creationist canards (lies) [regarding thermodynamics] ..." and "... these thermodynamics howlers ..." written by Paul R. Gross (an evolutionist) in his review of a book edited by Matt Young and Taner Edis entitled Why Intelligent Design Fails: A Scientific Critique of the New Creationism.
Note that these examples of attacking the person rather than the scientific claims as exemplified are used by both creationists and evolutionists (two each of the four examples). It is reprehensible whichever side does it.
2. Ad ignorantiam: using the ignorance of one's opponent as evidence of the correctness of one's own position. (See rhetorical device 1, "ad hominem," above.)
3. Loaded words. "We all have naturalism in our bones and even conversion [to Catholicism] does not at once work the infection out of our system." (Citing of C. S. Lewis by Dembski; emphasis mine.) Infection is an excellent example of a loaded word, as is easily demonstrated by replacing infection with a neutral word. For example: "We all have naturalism in our bones and even conversion [to Catholicism] does not at once work our prior beliefs out of our system." (The difference between the two statements is emphasized in the italicized words.)
"Methodological atheism": Phillip Johnson is talking about the scientific method, which scientists use and which may reasonably be said to be naturalistic. Creationists have no comparable method, which frequently hurts the creationist arguments where the issue is one of whether intelligent design is or is not scientific. Thus, if you insinuate that the scientific method is atheistic, you tend to reduce the importance of the scientific method in the reader's mind. Since naturalism (or materialism) is logically independent of theology (see chapter 2, section B.4, "Logic/epistemology"), their mixing is particularly loose.
Some creationist advocates have favored the term creation science as a means of suggesting that it, too, is scientific. Evolutionary scientists in return have scornfully referred to creation science as an oxymoron-a loaded term if there ever was one. (An oxymoron is a term that is inherently self-contradictory. Notable examples include "deafening silence," "civil war," "friendly fire," "jumbo shrimp," "original copy," and, yes, some people maintain, "military intelligence." Students at Occidental College in Los Angeles have any number of "Oxymoron" jokes.) Certainly the level of emotion in our example would be greatly reduced by saying instead that creation science is not in fact scientific. (See "Rhetorical Devices," in this section)
Another example of loaded words is the following humorous conjugation of verb forms such as "I am persevering, you are stubborn, he is pigheaded."
Examples of loaded words can be seen in a discussion of peppered-moth selection involving a creationist (Jonathan Wells) and two evolutionists (Kevin Padian and Alan Gishlick). Wells wrote a book, Icons of Evolution: Science or Myth?, that Padian and Gishlick reviewed. The data at issue are from peppered-moth studies carried out by H. B. D. Kettlewell.
Kettlewell's research is about moths that are generally peppered or very light in color. They spend most of their lives perching on the bark of trees. In the mid 1800s, when the industrial revolution was occurring, industry smokestacks were emitting much soot and thereby blackening the trees in industrial British cities like London and Manchester and their neighbors. And about that time someone found a previously unseen dark moth. As the trees got blacker, the frequency of dark moths increased, reaching sometimes to 98 percent. With an interest in preserving the environment, laws were passed to reduce the pollution. To no surprise for a Darwinist, the frequency of the dark moths declined again as the blackness of the trees declined.
How might this have occurred? Birds are known predators of these moths, and it was soon suggested that the increase of dark moths was a matter of camouflage. When the bark of trees was black, dark moths were difficult for the birds to see, but when the bark of trees was whitish, peppered moths were the variant that were difficult to see and thus their chances of survival were enhanced. The positive correlation between the blackness of the trees and the frequency of dark moths supports the proposition of natural selection going on before your eyes. Kettlewell illustrated the camouflage by pinning a peppered and a dark moth side by side on a dark tree trunk and also a similar pair on a light-colored tree. It was astonishing how well the dark moths blended in with the blackened trunk, and equally astonishing how the peppered moths blended in with the light-colored trunk.
But things are not quite as simple as they may at first appear. The Kettlewell study was incomplete in that it failed to properly consider other possible factors, such as migration of moths from surrounding areas that could have overwhelmed the influence of selection. The Kettlewell study also gave undue emphasis to moths resting on tree trunks and failed to consider that birds see ultraviolet light much better than humans and thus might have been able to detect moths that are well camouflaged to human eyes. There are unanswered questions, but the evidence for differential survival in agreement with the selection hypothesis is basically sound, despite the incompleteness of the Kettlewell study.
Wells published a rejoinder to criticisms raised by Padian and Gishlick-criticisms that included pejorative phrases like "notorious peppered moth experiments," "staged photos of moths on tree trunks," and "the statistic is bogus." (Emphases mine.) The statistic arises from the observation of forty-seven peppered moths observed resting in the wild, of which twelve were resting on a tree trunk, giving 12/47 = 0.225 of the resting peppered moths located on tree trunks. This was hardly the critical measurement of the study, but it can be said to demonstrate the assertion that peppered moths do rest, in sizable numbers, on tree trunks. That is important, not bogus. In conclusion, loaded words should not be used to attempt to sway your audience.
4. Repetition. "Testing Darwinism by the molecular evidence has never been attempted. ... The true scientific question-Does the molecular evidence as a whole tend to confirm Darwinism when evaluated without Darwinist bias?-has never been asked." Repetition is a form of emphasis present in the two phrases "has never been attempted" and "has never been asked." Moreover, "Darwinist bias" would be unloaded were it altered to "the Darwinist view."
F. Other Terms Relevant in Logical Analysis
1. Bias: Any assumption, often unrecognized, that tends to cause the experiment to produce inaccurate answers, pushing the results in one direction. (See objectivity and subjectivity below.)
2. Objectivity: A scientist's goal, reflecting the scientist's attempt to see what is there in his experiments rather than what he hopes, believes, or expects is there. It is the overcoming of one's personal biases or inclinations. This is something that is often difficult to achieve. A common phrase is "If I hadn't seen it, I wouldn't have believed it." This typifies the nature of objectivity. A different humorous phrase, also typifying objectivity, is "If I hadn't believed it I wouldn't have seen it." Shakespeare seems to have recognized the problem:
HAMLET: Do you see yonder cloud that's almost in shape of a camel?
POLONIUS: By the mass, and 'tis like a camel, indeed.
HAMLET: Methinks it is like a weasel.
POLONIUS: It is backed like a weasel.
HAMLET: Or like a whale?
POLONIUS: Very like a whale.
Wishful thinking can often lead us to accept "evidence" that would be rejected by a more objective observer. For example, a primitive human called "Nebraska Man" was once thought to have existed, based on the evidence of a tooth. It was found later that the tooth was not from a human but from an extinct peccary (a piglike hoofed mammal), and had been misidentified as being primitive human. Other examples include the "Paluxy Event" and the "Piltdown Affair." (See the discussion in sections I and J of chapter 4.) In a more famous example, Martin Fleishmann and Stanley Pons claimed to have produced "cold fusion" in 1989-but this claim has not been accepted by the scientific community. A case of wishful thinking? In science, it is best to proceed with a good dose of humility.
3. Subjectivity: The misreading of evidence because of personal beliefs. (See bias and objectivity above). Problems associated with bias, (lack of) objectivity, and subjectivity are common to evolutionists and creationists alike. But the two groups typically do not respond in the same manner.
Suppose there is disagreement over two proposed dates for the age of some event or artifact. The evolutionist, understanding the requirements of the scientific method, will ask whether his determination of the dating is repeatable on another sample from the same geographic site. The creationist, on the other hand, doesn't have much interest in repeatability except for its hoped-for conclusions. Then the lack of scientific repeatability is, for the creationist, evidence that the science is wrong and creationism is right. Of course, in the worst case for the scientist, both dates are quite wrong, whereas in the best case for the scientist, both dates are correct but with larger-than-hoped-for error bars. An extreme example of this sort is the date for the Earth's origin.
4. Relevance: the appropriateness of an argument for the question being asked.
5. Moot: no longer relevant. For example, the question "Did any dinosaurs survive their great extinction at the end of the cretaceous 65 million years ago?" would become moot if a fossil dinosaur were to be found that dates to more recently than 65 M.Y.A.
6. Implication: a proper conclusion, given acceptance of the prior assertions (the premises). Whenever it is impossible for A to be true without B also being true, it is said that A strictly implies B. Although the word entails is sometimes used as a synonym for implies, some logicians (notably Alan Ross Anderson and Nuel D. Belnap) have argued that for A to entail B, not only must it be impossible for A to be true without B being true, but there must be some relevance between the truth of A and the truth of B. For example, a contradiction implies the truth of any proposition whatsoever: "Wolves eat meat and wolves do not eat meat" logically implies "The Earth was created six thousand years ago"; yet it entails only those propositions that are relevant (e.g., "Wolves eat sheep").
7. Invalid: not having the proper structure of a syllogistic argument. When the conclusion does not follow from the premises, the syllogism is said to be invalid. Even if the conclusion is true, and even if it is an observable fact, if the structure is not proper, the logic is invalid. It is possible to have a true conclusion in an invalid syllogism. The conclusion may be true, but since it does not follow from the premises, the syllogism is invalid.