LOGICAL FALLACIES IN SCIENTIFIC WRITING
by
Logic is the set of rules by which one can formulate convincing arguments. It is "the science of argument."(1) When presenting an argument, one takes a set of premises that are proven to be true, and uses logic to show how they prove a certain "foregone conclusion."(2) It is helpful to know that this type of argument is not just a presentation of facts, but is, rather, an effort to prove a conclusion that was previously reached.
The focus of this paper is on logical errors in scientific writings. These logical errors are known as fallacies. If an argume1nt contains a fallacy, then the conclusion will not necessarily be proven. Some fallacies are just accidental, but they can also be used to trap an unwary listener or reader into believing faulty conclusions. First, this paper will identify and describe logical fallacies, then a selection of scientific writing will be analyzed in light of those fallacies.
Most logical fallacies can be grouped into three general categories. These are material fallacies, fallacies of relevance, and verbal fallacies.(3) These three categories will be explained in detail in the sections to follow.
Material Fallacies
Anyone presenting an argument uses both premises and presuppositions. Premises are the starting points of an argument which can be proven, while presuppositions are the underlying assumptions which cannot be proved or disproved. Presuppositions are inevitable because of human finiteness and bias.(4) Since the presuppositions cannot be proved or disproved, they must be taken on faith. It is important to identify these presuppositions in order to distinguish them from the premises.
Material fallacies deal principally with a premise and its evidence. When the premises of an argument, or its evidence, contain material fallacies, the conclusion is not sufficiently proven. "Material fallacies arise out of the fabric (or 'material') used to express an argument."(5) The following are descriptions and examples of material fallacies.
False Cause Assuming that one event is caused by another, just because one happens after the other, is the fallacy of false cause. The two events could have both been caused by another event, or they could be totally unrelated. "More people die in hospitals than anywhere else. Therefore, going to a hospital causes death."(6)
Hasty Generalization A hasty generalization is a general rule that is formed from only a few examples, or examples that are really exceptions. "A bear lives at the zoo, therefore, all bears live at zoos."
Misapplied Generalization Generalizations applied to cases that are exceptions to the rule are said to be misapplied. "Tools are useful, therefore this hammer will be useful." One may not need a hammer, or the hammer may be broken.
False Dilemma When an argument overlooks alternative possibilities, it creates a false dilemma. "America: Love it or Leave it." (7)
Compound Question A compound question is one which is phrased in such a way so as to unfairly limit the possibilities of one's answer. "Are you still as selfish as you used to be?" Even if one answers "no," one would still be admitting that one had been selfish in the past. One subset of the compound question fallacy is the persuasive definition. Redefining the terms of an argument to make them support the conclusion is the persuasive definition fallacy.(8)
False Analogy When an analogy is drawn between dissimilar objects or ideas, it is called a false analogy. Comparing "apples and oranges" is a well known example of a false analogy.
Contradictory Premises A conclusion which is drawn from premises which cannot both be true at the same time is the fallacy of contradictory premises. "'What would happen if an irresistible force met an immovable object?' (One student's answer: 'An inconceivable smash!')"(9)
Circular Reasoning An argument which contains the fallacy of circular reasoning uses its conclusion as support of its premises. It uses "the original thesis as proof of itself."(10) "C. S. Lewis was a good author, because he wrote good books. I know he wrote good books because he was a good author."
Insufficient or Suppressed Evidence Someone who uses the fallacy of insufficient evidence draws a conclusion from only a few unrepresentative examples. "That type of car is poorly made; a friend of mine has one, and it continually gives him trouble." An argument that uses the fallacy of suppressed evidence uses as evidence only the facts that support the conclusion, disregarding the rest of the pertinent facts. This fallacy illustrates how the conclusion was formed before all the evidence for it was gathered, or even in spite of it. In scientific writing, this fallacy is seen in "a failure to look for evidence that will confirm or deny a proposed hypothesis," and it is also seen "when one believes an alternate explanation refutes another explanation without a comparison of the merits between the two explanations."(11)
Fallacies of Relevance
Fallacies of relevance deal principally with the relationship between the premise/evidence, and the conclusion of the argument. For example, someone who tries to prove a point using emotion, or who proves the wrong point, commits a fallacy of relevance. The point that is proved is usually "an issue about which people have strong opinions, so that no one notices how their attention is being diverted" from the real issue.(12) The following are descriptions and examples of fallacies of relevance.
Irrelevance An argument is irrelevant if it proves or disproves the wrong point. This fallacy is really a broad category that includes almost all of the fallacies of relevance. "In a discussion of the relative safety of different makes of car, for instance, the issue of which cars are made domestically and which are imported is a red herring."(13)
Personal Ridicule Someone who ridicules his opponent instead of addressing the premises of the argument commits this fallacy. "You wouldn't believe someone with his political views would you?" One type of the personal ridicule fallacy is the 'straw man.' When someone uses this fallacy, he applies a characterization or stereotype to his opponents to make them easy to refute. For example, saying that "a person who advocates reduced military spending is . . . in favor of giving in to the Russians," is a straw man fallacy.(14)
Appeal to the People Using the feelings, actions, and/or prejudices of the general populous as a support of an argument may invalidate it. "Everyone's doing it!"(15)
Appeal to Authority Using the opinion of an expert in a field other than the one being discussed may invalidate the argument. "Coke is the favorite soda of 9 out of 10 actors, therefore we should have Coke at our picnic."
Appeal to Ignorance Assuming that a premise is correct because it can't be disproved displays the fallacy of ignorance. This is the "guilty until proven innocent" fallacy. "A classic example is this statement by Senator Joseph McCarthy, when asked to back up his accusation that a certain person was a communist: 'I do not have much information on this except the general statement of the agency that there is nothing in the files to disprove his Communist connections."(16)
Appeal to Pity An argument that uses this fallacy may be invalid because it depends on the idea that one will be more likely to accept the conclusion if one feels sorry for someone or something associated with it. This is the "victim" mentality. "I know I flunked every exam, but if I don't pass this course, I'll have to retake it in summer school. You have to let me pass!"(17)
Appeal to Force Threats and intimidations used to force someone to accept an argument constitute an appeal to force. "If you don't do what I tell you, you'll lose your job!"
Appeal to Money Advertisers frequently appeal to the desire to save money or get more money to induce people to make purchases. Despite their success, their appeals are fallacious. "Buy our products and save up to $50 every year!"
Emotive Language Using a word, phrase, or argument only to stimulate emotions invalidates ones argument. "President Clinton's best allies are the Clinton Haters."(18) The author of this quote used the term "Clinton Haters" to stimulate emotions. He described the "Clinton Haters" as willing to "say anything and charge him [Clinton] with anything that comes out of their heads when they get out of bed in the morning." He gives no evidence that anyone that impulsive actually exists. In this case, this fallacy is similar to the personal ridicule fallacy.
Tu Quoque This fallacy is used as a defense, where the person being criticized accuses his critic of doing the same thing himself. ("Tu quoque" means "you too."(19)) "Son, it is your bedtime. Go to bed." "But dad, you are staying up!"(20)
Genetic Error When someone disregards a premise or an argument only because of where it came from, they commit a genetic error. "The source of an argument is irrelevant so far as logical proof is concerned."(21) "[Clinton's] lieutenants . . . dismiss even legitimate questions as products of 'the attack machine.'"(22)
Anthropomorphism When someone projects human feelings and qualities to animals and inanimate objects,(23) he commits a fallacy of anthropomorphism. "After millions of years of work, Nature had created many diverse species of plants and animals."
Non Sequitur When the premises of an argument are not logically connected to the
conclusions, the argument contains a non sequitur. "Trees are green; therefore human beings enjoy spinach."(24)
Verbal Fallacies
Verbal fallacies deal principally with the misusage of words. An argument which contains "improper or ambiguous use of words"(25) is invalid. Here are some descriptions and examples of verbal fallacies.
Ambiguity Using undefined words or words whose meaning is vague constitutes an ambiguity. For example, in 1997 the Commonwealth of Virginia proposed buying "probe kits" for every student to help in math. Regarding this ambiguity, C. R. Taft said, "To be sure, there is the matter of 6,000 'probe kits,' or data-collection devices. What data these devices collect and how they do so was never defined clearly."
Equivocation Someone who uses a word in more than one sense, but gives the impression that only one meaning was meant, is using an equivocation. Anyone who presents an argument needs to use only one definition for each of his terms. When more than one definition is used for a certain word, it can cause confusion and be misleading. "Death is a subject of utmost gravity. Gravity is what keeps us from falling off the Earth. Thus, death is primarily what keeps us from falling off the Earth."(26)
Composition Assuming that a group will have the same qualities as the individuals in it is the fallacy of composition. This fallacy and the next one are types of equivocation. "In the fallacy of composition, the individual terms that comprise a group . . . are equivocally confused with the collective term."(27) "A spider is a beneficial member of an ecosystem. Therefore, introducing millions of spiders into an ecosystem would be advantageous."(28)
Division When one assumes that the individuals in a group will have the same qualities as the group they are in, one commits the fallacy of division. "That orchestra is the best in the world, therefore it is made up of the best musicians in the world." However, the best orchestra in the world may not have the world's best solo violinist.
Amphibology A sentence that is structured in such a way as to make more than one interpretation possible is an amphibology. "Wanted to sell: A highchair for a baby with a broken leg."(29)
Abstraction Taking a quote out of context is known as abstraction. Using this fallacy can totally change what was originally meant. Francis Bacon purportedly said, "Philosophy inclineth a man's mind to atheism." But what he actually said was, "A little philosophy inclineth man's mind to atheism, but depth in philosophy bringeth men's minds about to religion."(30)
Identifying logical fallacies is an important skill for everyone to have. It not only helps one to avoid accepting false conclusions, but it also helps one to learn better reasoning and debating skills. The process of looking for logical fallacies can help one to better understand the subject one is reading about or discussing. Knowing how to identify fallacies and how to avoid using them, can make one better prepared to refute false ideas and present the truth. This skill can be especially useful when trying to refute Darwinism. The next section will give some examples of scientific writing, and illustrate any fallacies they use to support their claims.
...in Scientific Writing
In this section several examples of scientific writing will be examined, to see if they contain logical fallacies. One must first identify the conclusions which are presented and the evidence that supports them. This evidence in scientific writing is the data presented in support of the hypotheses. Second, the evidence needs to be examined for any faults it might contain. However, since all scientists have presuppositions which can affect the selection and interpretation of data,(31) one must also analyze those presuppositions. Faulty data can be uncovered by using the scientific method, but biased presuppositions are more difficult to detect. It is always helpful just to identify the presuppositions and keep them in mind when examining the data.(32) Third, the reasoning that leads to the conclusions needs to be examined for logical fallacies. Some of the fallacies that will be encountered in the following examples of scientific writing include compound questions, insufficient and suppressed evidence, non sequitur, false cause, and irrelevance. The fallacies of insufficient/suppressed evidence and irrelevance relate to the selection and significance of data, while compound questions, non sequiturs, and false cause relate to the reasoning used to reach the conclusion.
The first example to be examined is from the book, The Mythmaker's Magic, in which D. McKown tried to discredit scientific creationism. To do this, he tried to show that there can be no scientific evidence for creation. "Anybody, whether scientifically trained or not, who believes the universe to be an artifact [i.e., created] does so on nonscientific grounds - grounds of intuition, hope, trust, or whatever."(33) In support of this conclusion, he used a definition of science that is based on naturalistic presuppositions. He defined scientific as "what astronomers, physicists, chemists, geologists, biologists, and other people who investigate nature do when they are on the job."(34) That brings up the question, what do scientists do when they are on the job? According to McKown, "scientists investigate the nature of what is available to human brains through experience," and "scientific knowledge is the knowledge of nature, not of supernature."(35) McKown then used this contrived definition of science to make belief in creation nonscientific. His reasoning went like this: science cannot be supernatural, creation is supernatural, therefore, creation cannot be scientific. McKown concluded that there can be no scientific evidence for creation, and the evidence he gave to support this conclusion was a naturalistic definition of science. McKown's definition of science makes it impossible to have any theory or hypotheses that involves the supernatural. This type of reasoning is called a 'persuasive definition,' which is a logical fallacy. By using a persuasive definition, McKown dismissed the possibility of any scientific evidence for creation, but also invalidated his argument. He further invalidated his line of reasoning by characterizing creationists as people who reject all science, thus ridiculing the 'straw man' of creationism. These fallacies in McKown's reasoning reveal the weaknesses in his argument.
The next example of scientific writing to be examined is from the article, "Teens, Insulin, and Heart Disease," from Science News. The article is a report of a study that examined the relationship between insulin resistance in teens and their risk of heart disease. Insulin is a hormone produced by the body as a signal to cells to absorb sugar from the blood. Insulin resistance is a disorder "in which cells ignore insulin's message to take up the sugar. The body responds to the continued presence of glucose by pumping out more insulin, which some researchers suspect may play a role in the development of heart disease." The study found that teens with insulin resistance typically had a higher concentration of "fats known to be associated with heart disease" in their blood. Commenting on this study, Theodore A. Kotchen said that if at-risk adolescents can be taught to eat a low-fat diet and exercise faithfully, they may be able to keep their hearts healthy well into the future.
A person by the name of P. Harding wrote a letter to the editor of Science News pointing out that there was a fallacy in the reasoning used by Mr. Kotchen. Kotchen's reasoning went like this: 1) insulin could "play a role in the development of heart disease"; 2) people with insulin resistance produce overdoses of insulin when there is sugar in their blood; 3) teens with insulin resistance also have more fat molecules in their blood (which is bad for their heart); and 4) therefore teens should eat less fat. Harding pointed out that although a low-fat diet may be helpful, the study gives more support to a low-sugar diet, which would decrease the amount of insulin produced. Therefore Harding concluded that the low-fat diet is not supported by this study, while the study would support a low-sugar diet. The reasoning used by Mr. Kotchen was based on a non-sequitur, that is, the conclusion did not follow from the facts presented.
While this author was pleased by Harding's identification of a logical fallacy, it must be pointed out that Harding's reasoning may also contain a fallacy. The study that was reported in Science News only showed that there is a relationship between insulin resistance and high levels of fat in the blood. Therefore, any conclusion which tries to relate diet to insulin resistance is not supported by this study. To assume without further evidence that the high levels of fat in the blood and the harmful effects of insulin resistance are caused by one's diet would be the fallacy of false cause.
This next example is from the tape series, Cosmic Questions, by Robert Kirshner, a Harvard astronomer. In it, he gives an overview of modern astronomy. When Kirshner described the light emission of the sun, he noted that the light from the sun is the most intense in the range that we can see, and also that our atmosphere is transparent to optical light. He then used these facts to support the conclusion that the sun is very old. Since we can see visible light, he reasoned, and since our eyes evolved over eons on earth, therefore, the output of the sun must have been in the visible range during all the time that we evolved. He said, "this is evidence . . . that the sun has been nearly constant over the last four billion years or so, the time of the history of life on earth."
The problem with this argument is that there is no evidence that, if evolution were true, our eyes would have evolved to see the most intense type of light. Kirshner's reasoning should have gone like this: 1) we can see visible light, 2) our eyes evolved over eons on earth, 3) they must have evolved to see the most intense light available to them, 4) therefore, the output of the sun must have been in the visible range during all the time that we evolved. Even if one were to assume that the second proposition were true, the third proposition is still entirely speculation; there is no evidence that it is true. To assume that it is true would invalidate the argument because there is insufficient evidence to support the proposition. Furthermore, without the third proposition, it is a non-sequitur to conclude that the sun must have been constant for billions of years.
This argument is an example of the effect that one's presuppositions have on the interpretation of data. One could just as easily conclude from the given data that God made us see visible light because it would convey more useful information than any other type of radiation, and also that He made the sun peak in the visible part of the spectrum (and the atmosphere transparent to that light) so that we could have good a source of visible light.
The next example is from a TV special on creation and evolution. In that special, Stephen J. Gould was interviewed by Randall Balmer.
R. B. "Some creationists have advanced the argument that the Grand Canyon was formed in a matter of weeks, perhaps months. How would you, as a scientist, go about refuting that sort of argument?"
S. G. "I think you have to look at the details of the Grand Canyon sequence. In a way, it's a test case, because it's an outstanding, spectacular, visual phenomenon that they're going to have to encompass if they ever had any chance of providing an adequate explanation [of nature.] I suppose that they have to say that this deep canyon was opened by some kind of catastrophe that took the earth's surface and split it apart.
"But that's not the issue with the Grand Canyon. The issue with the Grand Canyon is that you have thousands of feet of strata that have been adequately geologically dated, and that represent a vast stretch of time. You have fossils throughout that sequence which are arranged vertically in the same sequence as the fossil record displays throughout the earth. Now, what possible interpretation could you give to that invariant fossil sequence except that it represents time? Wether or not you think it represents evolution, it certainly represents time. There's no way to explain why you get invertebrates in the lowermost strata, and then you begin to pick up certain vertebra life, and then you begin, only later after the Grand Canyon sequence to pick up mammal life. How can you produce all that in one event, namely, Noah's Flood, which is how they would like to explain the production of the strata.
"So I think the issue with the Grand Canyon, it isn't how you produce the hole in the ground. (Whether that was done in a week or so or whether as we would argue it took a it took a long, long time through the erosion of the Colorado River and the rise of the plateau.) It's the fact that in that hole in the ground you have thousands and thousands of feet of strata in a vertical sequence with a fossil record that is consistent with the universal, world-wide, order of fossils that can only represent the passage of substantial amounts of time. The so-called Biblical literalists, who call themselves Scientific Creationists, think that the earth is five to ten thousand years [old.] There's no way under natural law explanation [sic.] that you can make a sequence of strata thousands of feet thick with an invariant fossil sequence in that tiny stretch of time."
The logic in Gould's response to the hypothesis of the recent formation of the Grand Canyon is faulty in several points. His response focused on an irrelevant discussion of the fossil record. He basically said that there are two main features of scientific interest at the Grand Canyon. The first is the canyon itself, the "hole in the ground." The second is the strata visible in the hole, and the fossils they contain. The questions that scientists try to answer when studying these two features are, how did they form, when did they form, and how long did the formation take. If they can get an idea of how long the formation took, then that would be a limit on the age of the feature they are studying, and consequently a lower limit for the age of the earth. It is agreed that the strata was laid down by water, and that the canyon was carved out by water, but the creationists and evolutionists disagree on how long both of those processes took. If it took ages, like the evolutionists think, then the earth would have to be at least that old. However, if they formed quickly, then the earth could be just thousands of years old.
The creationist hypothesis that Gould is responding to deals only with the time involved in the formation of the canyon itself. They theorize that there was massive amounts of water that carved out the canyon quickly. Instead of responding to the theory using scientific data relating to something like the rate of erosion of the Colorado River, he brings up the separate question of the fossil record and the rate of rock strata formation. By claiming that the fossil record could only be formed over a long period of time, he concluded that it doesn't matter how long it took the canyon to form, the earth is still very old.
The question of the fossil record at the Grand Canyon is not, as Gould said, "the issue with the Grand Canyon." Gould himself referred to other parts of the world as giving the complete fossil sequence (mammal life only after the Grand Canyon sequence.) Although the formation of the fossil record is an important issue, it is not the main issue that is brought up by the existence Grand Canyon. The formation of the canyon is the most obvious question that interests scientists. The canyon is the "outstanding, spectacular, visual phenomena" that needs to be explained.
Several faults exist in Gould's discussion of the fossil sequence in the Grand Canyon. He concluded that the strata represent long periods of time, because the fossils in them show a progression of life from lower forms to higher forms. The lowest layers do contain only bacterial fossils, while the higher strata contain some remains of plants and ocean life. However, the details of the "progression" do not fit the pattern that an evolutionist would expect. Some of the so-called simple forms of life, like sponges, only appear in the higher strata of the Grand Canyon, while trilobites, "the most complex of all invertebrate creatures," appear in the lower strata of the canyon, before any other species of the same phylum.(36) This displays the fallacy of insufficient or suppressed evidence on the part of Gould.
Gould said, "Wether or not you think it [the fossil sequence] represents evolution, it certainly represents time." Here Gould implied that even if evolution were not true, the strata in the Grand Canyon are still very old because of the fossil record they contain. However, one would be using the assumption that evolution occurred in order to interpret the fossil record as proof that the strata represent long periods of time. If evolution did not occur, then a progression of fossils from simple forms of life to more complex forms would not imply that the strata that they are in took eons to form. There could be other explanations for the progression (which we
have already seen to be not as well defined a progression as the evolutionists would have us believe.) Without evolution, it does not follow that a fossil sequence represents eons of time.
Logical fallacies in scientific reasoning are encountered in many different places, from books and magazines to tapes and television. A thorough understanding of logical fallacies is good preparation for refuting false conclusions that are presented, no matter where we encounter them. By identifying the facts and conclusions in a scientific article, one can see their logical relationship. That relationship can then be examined for logical fallacies, which invalidate the argument. The ability to identify logical fallacies is especially useful when dealing with evolution.
Endnotes:
Bibliography
Austin, S. A. ed. Grand Canyon, Monument to Catastrophe. Santee, California: Institute for Creation Research, 1994.
Bell, K. Developing Arguments. Belmont, California: Wadsworth Publishing Company, 1990.
Chittick, D. E. The Puzzle of Ancient Man. Newberg, Oregon: Creation Compass, 1997.
Dionne, E. J. "The Clinton Haters." The Washington Post, 25 November 1997, A19.
Fackelmann, Kathleen. "Teens, Insulin, and Heart Disease." Science News, Vol. 152 (1997),
p. 251.
"Fallacy." Encyclopędia Britannica, 1964, IX, 50 - 51.
Flesch, R. The Art of Clear Thinking. New York: Barnes & Noble Books, 1951.
Kirshner, R. P. Cosmic Questions: Astronomy from Quark to Quasar. Springfield, VA: The Teaching Company Limited Partnership, 1996.
McKown, D. B. The Mythmaker's Magic. Buffalo, New York: Prometheus Books, 1993.
Overman, D. L. A Case Against Accident and Self-Organization. New York: Rowman & Littlefield Publishers, Inc., 1997.
Sahakian, W. S. and M. L. Sahakian. Ideas of the Great Philosophers. New York: Barnes & Noble Books, 1966.
Salmon, M. H. Introduction to Logic and Critical Thinking. San Diego: Harcourt Brace Jovanovich, Publishers, 1989.
Vos Savant, M. The Power of Logical Thinking. New York: St. Martin's Press, 1996.
Weston, A. A Rulebook for Arguments. Indianapolis: Hackett Publishing Company, 1987.
1. R. Flesch, The Art of Clear Thinking (New York: Barnes & Noble Books, 1951), p. 74.
2. Ibid., p. 62.
3. W. S. Sahakian, and M. L. Sahakian, Ideas of the Great Philosophers (New York: Barnes & Noble Books, 1966), p. 12. "Fallacy," Encyclopędia Britannica, 1964, IX, 50-51.
4. D. E. Chittick, The Puzzle of Ancient Man (Newberg, Oregon: Creation Compass, 1997), pp. 92-93.
5. M. Vos Savant, The Power of Logical Thinking (New York: St. Martin's Press, 1996), p. 81.
6. Ibid., p. 84.
7. A. Weston, A Rulebook for Arguments (Indianapolis: Hackett Publishing Company, 1987), p. 88.
8. Ibid.
9. Sahakian and Sahakian, p. 23.
10. Ibid., p. 20.
11. D. L. Overman, A Case Against Accident and Self-Organization (New York: Rowman & Littlefield Publishers, Inc., 1997), p.20.
12. Weston, p. 89.
13. Ibid.
14. Ibid., pp. 6-7.
15. Ibid., p. 85.
16. Ibid.
17. Ibid.
18. E. J. Dionne, "The Clinton Haters," The Washington Post, 25 November 1997, A19.
19. M. H. Salmon, Introduction to Logic and Critical Thinking (San Diego: Harcourt Brace Jovanovich, Publishers, 1989), p. 75.
20. Sahakian and Sahakian, p. 21.
21. Ibid., p. 22.
22. Dionne, A19.
23. Sahakian and Sahakian, p. 22.
24. Ibid., p. 20.
25. "Fallacy," IX, 51.
26. Vos Savant, p. 76.
27. Ibid., p. 77.
28. Ibid.
29. Sahakian and Sahakian, p. 13.
30. Ibid., p. 16
31. Chittick, p. 92.
32. Vos Savant.
33. D. B. McKown, The Mythmaker's Magic, (Buffalo, New York: Prometheus Books, 1993),
p. 39.
34. Ibid., p. 38.
35. Ibid., pp. 38-39.
36. S. A. Austin ed., Grand Canyon, Monument to Catastrophe, (Santee, California: Institute for
Creation Research, 1994), p. 147.