Anthony weston a rulebook for arguments 4th edition pdf

Book Reference

A Rulebook for Arguments

Weston, A. (2009). A rulebook for arguments (4th ed.). Indianapolis, IN: Hackett Publishing Company

A Rulebook for

Arguments Fourth Edition

Anthony Weston

II

Generalizations

Some arguments offer one or more examples in support of a generaliza- tion.

Women in earlier times were married very young. Juliet in Shake- speare's Romeo and Juliet was not even fourteen years old. In the Mid- dle Ages, thirteen was the normal age of marriage for a Jewish woman. And during the Roman Empire, many Roman women were married at age thirteen or younger.

This argument generalizes from three examples-Juliet, Jewish women in the Middle Ages , and Roman women during the Roman Empire-to "many" or most women in earlier times. To show the form of this argu- ment most clearly, we can list the premises separately, with the conclu- sion on the "bottom line" :

Juliet in Shakespeare's play was not even fourteen years old.

Jewish women during the Middle Ages were normally married at thirteen.

Many Roman women during the Roman Empire were married at age thirteen or younger.

Therefore, women in earlier times were married very young .

It is helpful to write short arguments in this way when we need to see ex- actly how they work.

9

10 7, UsE MORE THAN ONE EXAMPLE

When do premises like these adequately support a generalization? One requirement, of course, is that the examples be accurate. Re-

member Rule 3: start from reliable premises! If Juliet wasn't around four- teen, or if most Roman or Jewish women weren't married at thirteen or younger, then the argument is much weaker. If none of the premises can be supported, there is no argument at all. To check an argument's exam- ples, or to find good examples for your own arguments, you may need to do some research .

But suppose the examples are accurate. Even then, generalizing from them is a tricky business. The rules in this chapter offer a short checklist for assessing arguments by example.

Use more than one example

A single example can sometimes be used for the sake of illustration. The example of Juliet alone might illustrate early marriage. But a single example offers next to no support for a generalization. Juliet alone may just be an exception. One spectacularly miserable billionaire does not prove that rich people in general are unhappy. More than one exam- ple is needed.

NO:

French fries are unhealthy (high in fat).

Therefore, all fast foods are unhealthy.

YES:

French fries are unhealthy (high in fat).

Milkshakes are unhealthy (high in fat and sugar).

Deep-fried chicken and cheeseburgers are unhealthy (high in fat).

Therefore, all fast foods are unhealthy.

The "Yes" version may still be weak (Rule 11 returns to it), but it certainly gives you much more to chew on, so to speak, than the "No" version.

8. UsE REPRESENTATIVE EXAMPLES I I

In a generalization about a small set of things, the strongest argument should consider all, or at least many, of the examples. A generalization about your siblings should consider each of them in turn, for instance, and a generalization about all the planets in the solar system can do the same.

Generalizations about larger sets of things require picking out a sam- ple. We certainly cannot list all women in earlier times who married young. Instead, our argument must offer a few women as examples of the rest. How many examples are required depends partly on how represen- tative they are, a point the next rule takes up. It also depends partly on the size of the set being generalized about. Large sets usually require more examples. The claim that your town is full of remarkable people requires more evidence than the claim that, say, your friends are remarkable people. Depending on how many friends you have, even just two or three examples might be enough to establish that your friends are remarkable people; but, unless your town is tiny, many more examples are required to show that your town is full of remarkable people.

Use representative examples

Even a large number of examples may still misrepresent the set being gen- eralized about. A large number of examples of ancient Roman women, for instance, might establish very little about women generally, since ancient Roman women are not necessarily representative of other women. The argument needs to consider women from other early times and from other parts of the world as well.

Everyone in my neighborhood favors McGraw for president. There- fore, McGraw is sure to win.

This argument is weak because single neighborhoods seldom represent the voting population as a whole. A well-to-do neighborhood may favor a can- didate who is unpopular with everyone else. Student wards in university towns regularly are carried by candidates who do poorly elsewhere. Be- sides, we seldom have good evidence even about neighborhood views. The set of people eager to display their political preferences to the world is probably not a representative cross-section of the neighborhood as a whole.

12 8. USE REPRESENTATIVE EXAMPLES

A good argument that "McGraw is sure to win" requires a represen- tative sample of the entire voting population. It is not easy to construct such a sample. Public opinion polls, for instance, construct their sam- ples very carefully. They learned the hard way. The classic example is a 1936 poll conducted by the Literary Digest to predict the outcome of the presidential contest between Roosevelt and Landon. Names were taken, as they are now, from telephone listings, and also from auto- mobile registration lists . The number of people polled was certainly not too small: more than two million "ballots" were counted. The poll pre- dicted a wide victory for Landon. In the event, though, Roosevelt won easily. In retrospect it is easy to see what went wrong . In 1936, only a select portion of the population owned telephones and cars. The sample was sharply biased toward wealthy and urban voters, more of whom supported Landon.

Polls have improved since then . Nonetheless, there are still worries about the representativeness of their samples, and they still regularly forecast elections wrong. For example, these days most of my students don't have landlines at all-only cell phones with unlisted numbers. The pollsters aren't calling them. Phone polls may actually be getting less rep- resentative again.

It is often an open question, then, just how representative a given sam- ple may be. Anticipate this danger! Do some research. Juliet, for exam- ple, is just one woman. Is she representative of women in her time and place? In Shakespeare's play, Juliet's mother says to her:

Think of marriage now; younger than you, Here in Verona, ladies of esteem, Are made already mothers. By my count, I was your mother much upon these years That yo u are now a maid ...

(1.3.69-73)

This passage suggests that Juliet's marriage at fourteen is not exceptional; in fact, fourteen seems to be a little on the old side.

In general, look for the most accurate cross-section you can find of the population being generalized about. If you want to know what students think about some subject at your university, don't just ask the people you know or generalize from what you hear in class. Unless you know quite

9. BACKGROUND RATES MAY BE CRUCIAL 13

a range of people and take quite a range of classes, your personal "sample" is not likely to mirror the whole student body. Similarly, if you want to know what people in other countries think about the United States, don't just ask foreign tourists-for of course they are the ones who chose to come here. A careful look at a range of foreign media should give you a more representative picture.

To persuade you that I am a first-rate ,archer, it is not enough to show you a bull's-eye I have made. You shollld ask (politely, to be sure), "Yes, but how many times did you miss?" Getting a bull's-eye in one shot tells quite a different story than getting a bull's-eye in, say, a thousand, even though in both cases I genuinely do have a bull's-eye to my name. You need a lit- tle more data.

Or again:

Leon's horoscope told him that he would meet a vivacious new stranger, and lo and behold he did! Therefore, horoscopes are reliable.

Dramatic as such an example may be, the problem is that we are only looking at one case in which a horoscope came true. To properly evalu - ate this evidence, we need to know something else as well: how many horoscopes didn't come true. When I survey my classes, we can usually find a few Leons out of twenty or thirty students. The other nineteen or twenty-nine horoscopes go nowhere. But a kind of prediction that comes true only once out of twenty or thirty tries is hardly reliable-it's just lucky once in a while. It may have some dramatic successes, like my archery, but its success rate may still be abysmal.

To evaluate the reliability of any argument featuring a few vivid ex- amples , then, we need to know the ratio between the number of "hits ," so to speak, and the number of tries. It 's a question of representativeness again. Are the featured examples the only ones there are? Is the rate im- pressively high or low?

Another case in point:

14 I 0. STATISTICS NEED A CRITICAL EYE

The "Bermuda Triangle" area off Bermuda is famous as a place where many ships and planes have mysteriously disappeared. Avoid it at all costs! There have been several dozen disappearances in the past decade alone.

No doubt. But several dozen out of how many ships and planes that passed through the area? Several dozen, or several hundred thousand? If only twenty, say, have disappeared out of maybe two hundred thousand, then the disappearance rate in the Bermuda Triangle may well be normal, or even unusually low-certainly not mysterious.

Statistics need a critical eye

Some people see numbers-any numbers-,-in an argument and con-.., elude from that fact alone that it must be a good argument. Statistics seem to have an aura of authority and definiteness (and did you know that 88 percent of doctors agree?) . In fact, though, numbers take as much critical thinking as any other kind of evidence. Don't turn off your brain!

After an era when some athletic powerhouse universities were accused of exploiting student athletes, leaving them to flunk out once their eli- gibility expired, college athletes are now graduating at higher rates. Many schools are now graduating more than 50 percent of their athletes.

Fifty percent, eh? Pretty impressive! But this figure, at first so persuasive, does not really do the job it claims to do.

First, although "many" schools graduate more than 50 percent of their athletes, it appears that some do not-so this figure may well exclude the most exploitative schools that really concerned people in the first place.

The argument does offer graduation rates. But it would be useful to know how a "more than 50 percent" graduation rate compares with the graduation rate for all students at the same institutions. If it is signifi- cantly lower, athletes may still be getting the shaft.

Most importantly, this argument offers no reason to believe that college athletes' graduation rates are actually improving, because no comparison

I 0. STATISTICS NEED A CRITICAL EYE 15

to any previous rate is offered! The conclusion claims that the graduation rate is now "higher," but without knowing the previous rates it is impos- sible to tell.

Numbers may offer incomplete evidence in other ways too. Rule 9, for example, tells us that knowing background rates may be crucial. Corre- spondingly, when an argument offers rates or percentages, the relevant background information usually must include the number of examples. Car thefts on campus may have doubled, but if this means that two cars were stolen rather than one, there's not much to worry about.

Another statistical pitfall is over-precision:

Every year this campus wastes 412,067 paper and plastic cups. It's time to switch to reusable cups!

I'm all for ending waste too, and I'm sure the amount of campus waste is huge. But no one really knows the precise number of cups wasted-and it's extremely unlikely to be exactly the same every year. Here the ap- pearance of exactness makes the evidence seem more authoritative than it really is.

Be wary, also, of numbers that are easily manipulated. Pollsters know very well that the way a question is asked can shape how it is answered. These days we are even seeing "polls" that try to change people's minds about, say, a political candidate, just by asking loaded questions ("If you were to discover that she is a liar and a cheat, how would that change your vote?"). Then too, many apparently "hard" statistics are actually based on guesswork or extrapolation, such as data about semi-legal or illegal activities. Since people have a major motive not to reveal or report things like drug use, under-the-counter transactions, hiring illegal aliens, and the like, beware of any confident generalizations about how widespread they are.

Yet again:

If kids keep watching more TV at current rates, by 2025 they'll have no time left to sleep!

Right, and by 2040 they'll be watching thirty-six hours a day. Extrapola- tion in such cases is perfectly possible mathematically, but after a certain point it tells you nothing.

16 I I . CoNSIDER COUNTEREXAMPLES

Consider counterexamples

Counterexamples are examples that contradict your generalization. No fun-maybe. But counterexamples act~ally can be a generalizer 's best friends, if you use them early and use them well. Look for them on pur- pose and systematically. It is the best way to sharpen your own general- izations and to probe more deeply into your theme.

Consider this argument once again:

French fries are unhealthy (high in fat).

Milkshakes are unhealthy (high in fat and sugar).

Deep-fried chicken and cheeseburgers are unhealthy (high in fat).

Therefore, all fast foods are unhealthy.

This argument offers multiple and apparently representative examples. However, as soon as you start thinking about counterexamples instead of just more examples, you will find that the argument overgeneralizes. Sub- way sandwiches, for example, are "fast food" as well, but vegetables and buns are the primary ingredients, meats and cheeses are add-ons, and nothing is deep-fried. So it turns out that not all fast foods are unhealthy.

If you can think of counterexamples to a generalization that you want to defend , then you need to adjust your generalization. If the last argu- ment were yours, for instance, you might change the conclusion to "Many fast foods are unhealthy."

Such a counterexample may also prompt you to think more deeply about what it is about fast foods that tends to make them unhealthy. Is it partly that deep-frying-with the huge fat load that results-is such a quick and easy way of cooking? Highly processed foods, such as fast-food meat and cheese and milkshake ingredients, also tend to be fattier or un- healthy in other ways. So maybe what you really want to say is that the demand for quick cooking and cheap, standardized ingredients tends to make the results less healthy (although this is not invariable, as the exam- ple of subway sandwiches suggests). This is a more subtle and interesting claim than the original one, and gives your thinking more room to move.

I I . CoNSIDER couNTEREXAMPLES 17

Ask yourself about counterexamples when you are assessing others' arguments as well as evaluating your own. Ask whether their conclusions might have to be revised and limited, or rethought in more subtle and complex directions. The same rules apply both to others' arguments and to yours. The only difference is that you have a chance to correct your overgeneralizations yourself.

Ill

Arguments by Analogy

There is an exception to Rule 7 ("Use more than one example"). Argu- ments by analogy, rather than multiplying examples to support a gener- alization, argue from one specific example to another, reasoning that because the two examples are alike in many ways, they are also alike in one further specific way.

For example, here is how a doctor argues that everyone should have a regular physical checkup:

People take in their car for servicing and checkups every few months without complaint. Why shouldn' t they take similar care of their bodies? 4

This argument suggests that getting a regular physical checkup is like tak- ing your car in for regular servicing. Cars need that kind of attention- otherwise, major problems may develop. Aren't our bodies like that too?

People should take their cars in for regular service and checkups (otherwise major problems may develop).

People's bodies are like cars (because human bodies, too, are complex systems that can develop problems if not regularly checked up) .

Therefore, people should take themselves in for regular "service" and checkups too.

4 Dr. John Beary III, quoted in "News You Can Use," U.S. News and World Re- port, 11 August 1986, p. 61.

19

20 ARGUMENTS BY ANALOGY

Notice the italicized word "like" in the second premise. When an argu- ment stresses the likeness between two cases, it is very probably an ar- gument from analogy.

Here is another striking example.

An interesting switch was pulled in Rome yesterday by Adam Nord- well, an American Chippewa chief. As he descended his plane from California dressed in full tribal regalia, Nordwell announced in the name of the American Indian people that he was taking possession of Italy "by right of discovery" in the same way that Christopher Colum- bus did in America. "I proclaim this day the day of the discovery of Italy," said Nordwell. "What right did Columbus have to discover America when it had already been inhabited for thousands of years? The same right I now have to come to Italy and proclaim the discov- ery of your country."5

Nordwell is suggesting that his "discovery" of Italy is like Columbus's "discovery" of America in at least one important way: both Nord well and Columbus claimed a country that already had been inhabited by its own people for centuries. Thus, Nordwell insists that he has as much "right" to claim Italy as Columbus had to claim America. But, of course, Nord- well has no right at all to claim Italy. It follows that Columbus had no right at all to claim America.

Nord well has no right to claim Italy for another people, let alone "by right of discovery" (because Italy has been inhabited by its own people for centuries).

Columbus's claim to America "by right of discovery" is like Nordwell's claim to Italy (America, too, had been inhabited by its own people for centuries).

Therefore, Columbus had no right to claim America for another people, let alone "by right of discovery."

How do we evaluate arguments by analogy? The first premise of an argument by analogy makes a claim about the

example used as an analogy. Remember Rule 3: make sure this premise

5 Miami News, 23 September 1973.

12. ANALOGIES REQUIRE RELEVANTLY SIMILAR EXAMPLES 21

is true. It's true that cars need regular service and checkups to keep ma- jor problems from developing, for instance, and it 's true that Adam Nord- well could not claim Italy for the Chippewa.

The second premise in arguments by analogy claims that the example in the first premise is like the example about which the argument draws a conclusion. Evaluating this premise is harder and needs a rule of its own.

Analogies requir~ relevantly similar examples

Arguments by analogy do not require that the example used as an analogy be exactly like the example in the conclusion. Our bodies are not just like cars, after all. We are flesh and bone, not metal; we don't have wheels or seats or windshield wipers. Analogies require relevant similarities. What cars are made of or exactly what their parts are is irrelevant to the doctor's point. The argument is about the upkeep of complex systems.

One relevant difference between our bodies and our cars is that our bodies do not need regular "service" in the way our cars do. Cars regularly need oil changes, new pumps or transmissions, and the like. But replacing body parts or fluids is much rarer: think organ transplants or blood trans- fusions. On the other hand, it's true that we need regular checkups- otherwise, problems can develop undetected-and older and strenuously used bodies, like older and higher mileage cars, may need checkups more often. So the doctor 's analogy is partly successful. The "service~' part is somewhat weak, in my view, but the checkup part is persuasive.

Likewise, twentieth-century Italy is not just like fifteenth-century America. Italy is known to every twentieth-century schoolchild, whereas America was unknown to much of the world in the fifteenth century. Nordwell is not an explorer, and a commercial jet is not the Santa Maria. But these differences are not relevant to Nordwell's analogy. Nordwell simply means to remind us that it is senseless to claim a coun- try already inhabited by its own people. Whether that land is known to the world's schoolchildren, or how the "discoverer" arrived there, is not important. The more appropriate reaction might have been to try to es- tablish diplomatic relations, as we would try to do today if somehow the land and people of Italy had just been discovered. That's Nordwell's point, and, taken in that way, his analogy makes a good (and unsettling) argument.

22 12. ANALOGIES REQUIRE RELEVANTLY SIMILAR EXAMPLES

One famous argument uses an analogy to try to establish the existence of a Creator of the world. We can infer the existence of a Creator from the order and beauty of the world, this argument claims, just as we can infer the existence of an architect or carpenter when we see a beautiful and well-built house. Spelled out in premise-and-conclusion form:

Beautiful and well-built houses must have "makers": designers and builders.

The world is like a beautiful and well-built house .

Therefore, the world also must have a "maker": a Designer and Builder, God.

Again, more examples are not necessarily needed here. The argument turns on the similarity of the world to one well-understood example, a house.

Whether the world really is relevantly similar to a house, though, is not so clear. We know quite a bit about the causes of houses. But houses are parts of the world. We know very little, actually, about the structure of the world (the universe) as a whole or about what sorts of causes it might be expected to have. The philosopher David Burne discussed this argument in his Dialogues Concerning Natural Religion and asked:

Is part of nature a rule for the whole? ... Think [of how] wide a step you have taken when you compared houses ... to the universe, and from their similarity in some circumstances inferred a similarity in their causes .... Does not the great disproportion bar all comparison and inference? 6

Burne therefore suggests that the universe is not relevantly similar to a house. Houses indeed imply "makers" beyond themselves, but for all we know the universe as a whole may contain its cause within itself, or per- haps has some kind of cause unique to universes. This analogy, then, makes a poor argument. Some other kind of argument is probably needed if the existence of God is to be inferred from the nature of the world.

6 David Hume, Dialogues Concerning Natural Religion (1779; reprint, Indi- anapolis: Hackett Publishing Company, 1980), p. 19.

IV

Sources

No one can be an expert through direct experience on everything there is to know. We do not live in ancient times ourselves and therefore cannot know first-hand at what age women tended to marry back then. Few of us have enough experience to judge which kinds of cars are safest in a crash. We do not know first-hand what is really happening in Sri Lanka or the state legislature, or even in the average American classroom or street corner. Instead, we must rely on others-better-situated people, or- ganizations, surveys, or reference works- to tell us much of what we need to know about the world. We argue like this:

X (a source that ought to know) says that Y.

Therefore, Y is true.

For instance:

Carl Sagan says that there could be life on Mars.

Therefore, there could be life on Mars.

It's a risky business, though. Supposedly expert sources may be over- confident, or may be misled, or may not even be reliable. And everyone has biases, after all, even if innocent ones. Once again we must consider a checklist of standards that truly authoritative sources need to meet.

23

24 14. SEEK INFORMED SOURCES

Some factual assertions, of course, are so obvious or well known that they • ~ ~ +, ~ •

do not need support at all. IL lS usuauy~not,necessary to prove that the United States has fifty states or that Juliet loved Romeo . However, a pre- cise figure for the current population of the United States does need a ci- tation. Likewise, the claim that Juliet was only fourteen should cite a few Shakespearean lines in support.

N O:

I once read that there are cultures in which makeup and clothes are mostly men's business, not women's.

If you ' re arguing about whether men and women everywhere follow the gender roles familiar to us, this is a relevant example-a striking case of different gender roles. But few of us know anything about this sort of dif- ference first-hand. To nail down the argument, you need to call upon a fully cited source.

YE S :

Carol Beckwith, in "Niger ' s Wodaabe" (National Geographic 164, no. 4 [October 1983], pp. 483-509), reports that among the West African Fulani peoples such as the Wodaabe, makeup and clothes are mostly men's business.

Citation styles vary- you may need a handbook of style to find the ap- propriate style for your purposes- but all include the same basic infor- mation: enough so that others can easily find the source on their own .

Seek inforll)eCJ S,ources

Sources must be qualified w make the statements they make. Honda me- chanics are qualified to discuss the merits df different Hondas, midwives and obstetricians are qualified to discuss pregnancy and childbirth, teach- ers are qualified to discuss the state of their schools, and so on. These sources are qualified because they have the appropriate background and

14, SEEK INFORMED SOURCES 25

information. For the best information about global climate change, go to climatologists, not politicians.

Where a source's qualifications are not immediately clear, an argu- ment must explain them briefly. Carl Sagan says that there could be life on Mars, eh? But who is Carl Sagan? Here is the answer: Sagan was an astronomer and astrobiologist, a leader in the space program, and among the designers of the first Mars landers. (And, in the spirit of citing sources, I will add that you can find out more about him in William Poundstone 's biography, Carl Sagan: A Life in the Cosmos [New York: Henry Holt and Company, 1999].) When someone with a background like that says that there could be life on Mars, we should listen.

As you explain your source's qualifications, you can also add more ev- idence to your argument.

Carol Beckwith, in "Niger's Wodaabe" (National Geographic 164, no. 4 [October 1983], pp. 483-509), reports that among the West African Fulani peoples such as the Wodaabe, makeup and clothes are mostly men's business. Beckwith and an anthropologist colleague lived with the Wodaabe for two years and observed many dances for which the men prepared by lengthy preening, face-painting , and teeth-whitening. (Her article includes many pictures too.) Wodaabe women watch, com- ment, and choose mates for their beauty-which the men say is the nat- ural way. "Our beauty makes the women want us," one says.

Note that an informed source need not fit our general stereotype of an "authority"-and a person who fits our stereotype of an authority may not even be an informed source. If you're checking out colleges, for instance, students are the best authorities, not administrators or recruiters, because it's the students who know what student life is really like. (Just be sure to find yourself a representative sample.)

Note also that authorities on one subject are not necessarily informed about every subject on which they offer opinions.

Einstein was a pacifist. Therefore, pacifism must be right.

Einstein's genius in physics does not establish him as a genius in politi- cal philosophy. Likewise, just because someone can put the title "Doc- tor" before their name-that is, just because they have a PhD or MD in some field-does not mean that they are qualified to deliver opinions on

26 15. SEEK IMPARTIAL SOURCES

any subject whatsoever. (Not to name names or anything, but there are some quite prominently cited "Doctors" these days whose doctorates ac- tually have nothing to do with the fields in which they make very self- assured and widely publicized pronouncements.)

Sometimes we must rely on sources whose knowledge is better than ours but still limited in various ways. On occasion, the best information we can get about what is happening in a war zone or a political trial or in- side a business or bureaucracy is fragmentary and filtered through jour- nalists, international human rights organizations, corporate watchdogs, and so on. If you must rely on a source that may have limited knowledge in this way, acknowledge the problem. Let your readers or hearers decide whether imperfect authority is better than none at all.

Truly informed sources rarely expect others to accept their conclu- sions simply because they assert them. Most good sources will offer at least some reasons or evidence- examples, facts, analogies, other kinds of arguments- to help explain and defend their conclusions. Beckwith, for example, offers photographs and stories from the years she lived with the Wodaabe. Sagan wrote whole books explaining space exploration and what we might find beyond Earth. Thus, while we might need to take some of their specific claims on authority alone (for instance, we must take Beckwith at her word that she had certain experiences), we can ex- pect even the best sources to offer arguments as well as their own judg- ments in support of their general conclusions. Look for those arguments, then, and look at them critically as well.

Seek impartial sources

People who have the most at stake in a dispute are usually not the best sources of information about the issues involved. Sometimes they may not even tell the truth. People accused in criminal trials are presumed in- nocent until proven guilty, but we seldom completely believe their claims of innocence without confirmation from impartial witnesses . Readiness to tell the truth as one sees it, though, is not always enough . The truth as one honestly sees it can still be biased. We tend to see what we expect to see. We notice, remember, and pass on information that supports our point

15. SEEK IMPARTIAL SOURCES 27

of view, but we may not be quite so motivated when the evidence points the other way.

Therefore, look for impartial sources: people or organizations who do not have a stake in the immediate issue, and who have a prior and pri- mary interest in accuracy, such as (some) university scientists or statisti- cal databases. Don'tjust rely on politicians or interest groups on one side of a major public question for the most accurate information about the issues at stake. Don't just rely on manufacturers' advertisements for reli- able information concerning their products.

NO:

My car dealer recommends that I pay $300 to rustproof my car. He should know; I guess I'd better do it.

He probably does know, but he might not be entirely reliable, either. The best information about consumer products and services comes from independent consumer testing agencies, agencies not affiliated with any manufacturer or provider but answering to consumers who want the most accurate information they can get. Do some research!

YES:

Consumer Reports says that rust problems have almost disappeared in modern cars due to better manufacturing, and advises that dealer rust- proofing is not needed (see "Don't Waste Money on Unnecessary Ex- tras," Consumer Reports Buying Guide 2006, p. 153). Therefore, I don't need it!

Likewise, independent service professionals and mechanics are rela- tively impartial sources of information. For political matters, especially when the disagreements are basically over statistics, look to independent government agencies, such as the Census Bureau, or to university stud- ies or other independent sources. Organizations like Doctors Without Borders are relatively impartial sources on the human rights situation in other countries because they practice medicine, not politics: they are not trying to support or oppose any specific government.

Of course, independence and impartiality are not always easy to judge, either. Be sure that your sources are genuinely independent and not just in- terest groups masquerading under an independent-sounding name. Check

28 16. CROSS-CHECK SOURCES

who funds them; check their other publications; look for their track record; watch the tone of their statements. Sources that make extreme or sim- plistic claims, or spend most of their time attacking and demeaning the other side, weaken their own claims. Again, seek out sources that offer constructive arguments and responsibly acknowledge and thoroughly en- gage the arguments and evidence on the other side. At the very least, try to confirm for yourself any factual claim quoted from a potentially biased source. Good arguments cite their sources (Rule 13); look them up. Make sure the evidence is quoted correctly and not pulled out of context, and check for further information that might be helpful.

Cross-checl< sources

Consult and compare a variety of sources to see if other, equally good au- thorities agree. Are the experts sharply·diyided or in agreement? If they're pretty much in agreement, theirs is the safe view to take. (At the very least, if you propose to take a different view, you have some serious explaining to do.) Where even the experts disagree, though, it's best to reserve judg- ment yourself too. Don't jump in with two feet where truly informed people· tread with care. See if you can argue on some other grounds--Dr rethink your conclusions.

Authorities are most likely to agree about specific, factual matters. That Wodaabe men spend a great deal of time on clothes and makeup is a specific factual claim, for instance, and in principle not hard to verify. On larger and less tangible issues, it is harder to find authorities who agree. Can, or should, the U.S. Constitution be read in terms of the Founders' "original intent"? Do we have free will? Distinguished jurists disagree with each other; great philosophers have held opposing views. You can still quote some of them as authorities if you know that your au- dience already agrees with them and respects them (but then again, there's always that question: should you?). In general, though, do not ex- pect their mere assertions to carry authority. Once again, look to the ar- guments behind the assertions.

Remember, though: mere disagreement does not automatically dis- qualify a source. A few people may still disagree that the Earth is round, but it is not a genuinely open question. Likewise, although there was a time when experts disagreed about global climate change, the world sci-

17, UsE THE WEB WITH CARE 29

entific community is now nearly unanimous that it is occurring and needs to be addressed_? Sure, there's still controversy, but not among the ex- perts. You may need to look into disagreements such as these to decide how seriously to take them.

Use the Web with care

Enter a few keywords and the Web will give you truckloads of informa- tion on almost any question or.issue. All manner of views and topics are available, almost instantly, that would take forever to turn up if we had to search painstakingly and by hand in libraries or by correspondence.

Reliability, though, is quite another matter. Libraries have at least some checks on the reliability of the books and other materials they col- lect. Reputable publishers consult the community of experts before pre- senting any views as expert. Some publishers are even renowned for employing offices of fact-checkers. But on the Web anyone can say any- thing whatsoever, and with a little skill or money even the flimsiest opin- ion site can be dressed up to look sober-minded and professional. There are very few checks on the content of Web sites-often no checks at all.

Only rely on Web sources, then, if you are dealing with an identifiable and independently reputable source. Don't rely on a Web site at all un- less you have some idea of its source. Key questions are: Who created this site? Why did they create it? What are their qualifications? What does it mean if they don't tell you? How can you double-check and cross-check its claims?

Be aware that Web search engines do not search "everything"-far from it. They search only what is indexed, which is only 10 to 20 percent of the available Web, and heavily weighted toward merchandising and "hot" sites. Especially on controversial issues, where evidence and con- clusions are in dispute, the sites that come up first (and often are designed to come up first) are likely to be opinionated bluster from nonexperts with agendas. In fact, the best information is often found in databases or

7 See Climate Change 2007, Report of the Intergovernmental Panel on Climate Change, a global scientific effort established by the United Nations Environmen- tal Program and the World Meteorological Organization (Cambridge, UK: Cam- bridge University Press, 2007 , and on the Web at http://www.ipcc .ch/).

30 I 7. UsE THE WEB WITH CARE

other academic resources that standard search engines cannot enter at all. Normally you have to search within these databases to find the most re- liable articles or information on any given topic.

When you really need to know something, then, dig deeper than the standard Web search. What you'll get usually will require harder and more careful reading and thinking- which is what you want, of course- and sometimes a password (hopefully available to you as a student or li- brary patron) in turn. If you are preparing a research project for a class, your teacher should be able to guide you to appropriate Web resources. If not, ask your librarian!

v Arguments about Causes