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Mill’s Methods
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In the early 19th century, the philosopher John Stuart Mill identified the following four (or five) informal methods for establishing causal connections between types of events. 1. The Method of Agreement: Consider how epidemiologists attempt to converge on an alleged cause for
some disease outbreak (for instance, the recent endoscopy
scare in (1) Examine instances in which a certain effect occurs. The more variable these instances are, the better. (2) Try to identify a factor (or combination of factors) that is present in all of those instances. The method of agreement helps show that a certain factor (or factors) is necessary for bringing about a certain effect. One can use the method of agreement to undermine a causal link between an effect and some purported cause by showing that sometimes the effect occurs without the factor.
2. The Method of Difference (1) Compare situations in which a putative causal factor is present to ones in which it isn’t. The more similar these situations are in other respects, the better. (2) Determine whether there is any difference in the observed effect. The method of difference helps establish that a certain factor is sufficient for bringing about a certain effect. One can use the method of difference to undermine a causal connection by showing that the presence or absence of the factor makes no difference to the observed effect.
3. The Joint Method A combination of the methods of agreement and difference. Compare a variety of situations in which a certain factor is present to similar situations in which that factor is absent. Then show that a certain effect is observed in all and only those instances in which that factor is present.
4. The Method of Concomitant Variations Demonstrate that quantitative variations in an effect are systematically related to quantitative variations in a particular factor.
5. The Method of Residues Show that all of the factors known to have some influence upon a certain effect cannot explain the observed level of the effect. Then attribute the residual influence to an unexamined cause. The method of residues is most effective in cases where one cannot directly measure the level of influence a factor has over some effect. Counterexamples to Causal Claims: Although a single counterexample to a causal generalization is typically not sufficient to undermine the claim altogether, they do provide some disconfirming evidence. There are generally two types of counterexamples to a causal claim: (1) The first involves cases where the effect is present, but the alleged causal factor isn’t. This is a counterexample by the method of agreement; it shows that the alleged cause isn’t necessary for the effect to be present. (2) The second involves cases where the alleged cause occurs, but the effect does not. These are counterexamples by the method of difference. They show that the alleged causal factor is not sufficient on its own for bringing about the effect; that is, it might not make any difference at all. |
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Exercises Analyze each of the inductive
arguments below. Identify the purported cause, the purported effect, as well
as the method used to support the conclusion: agreement, difference, joint
method, method of concomitant variations, or residues. 1. Research shows that the A-1 Security Gadget increases safety levels at airports. We tested the device at four major airports, and in each case the number of concealed weapons detected increased over past months. 2. I think this wool sweater is giving me a rash, because I haven't changed body soap or clothing detergent, and nothing else could be causing me this problem. 3. Last fall's class was a perfect indicator of the effect of studying on one's class performance: the students who studied very little got D's, those who studied a bit more got C's, and those who studied regularly got B's and A's. 4. Rayblocker sunblock lotion is superior. We tested it on Kevin , Mary, Alicia, and Joe, putting Rayblocker on one arm and the leading brand on the other. They all went swimming for hours, and in each case the arms with Rayblocker were fine, while those with the leading brand were fried to a crisp. 5. The increased planting of trees in our cities must be contributing to the rapid rise of urban smog, for the levels of smog actually observed cannot be accounted for by industrial, residential, and automotive emissions alone. 6. In some cases, all a movie needs is stellar special effects to be a box-office hit. The Red Mission had good casting but a horrible plot, while The Star Destroyer had poor casting but an intricate plot. But both had great special effects and were smash hits. 7. Jiffy Squid fries are the best, and you know what the secret is? While the recipe, the potatoes, and everything else is the same as at Burger Thing, the fries at Jiffy Squid are cooked in oil that has been through the crankcase of a '57 Desoto. The result - mmm-mmm fries! 8. After reading his March 23 diatribe, it is clear to me that Review-Journal columnist Vin Suprynowicz has not yet learned the obvious: the more handguns a country has in circulation, the more handgun deaths that country is going to get -- not less. The If all these guns make us safer, we should be the safest nation on earth.
(LVRJ, 9. For those of you who watch what you eat, here's the final word on nutrition and health. It's a relief to know the truth after all those conflicting nutritional studies.
1. The Japanese eat very little fat and suffer fewer heart attacks than Americans. 2. The Mexicans eat a lot of fat and suffer fewer heart attacks than Americans. 3. The Chinese drink very little red wine and suffer fewer heart attacks than Americans. 4. The Italians drink a lot of red wine and suffer fewer heart attacks than Americans. 5. The Germans drink a lot of beers and eat lots of sausages and fats and suffer fewer heart attacks than Americans.
CONCLUSION: Eat and drink what you like. Speaking English is apparently what kills you. 10. Those famed vortices in Sedona must have caused me to get pregnant. There’s just no other possible explanation!
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This is a little trickier.
The following editorial both asserts (or rather
insinuates) one causal connection and then denies another. Identify
both of those claims and then the method or methods used to establish them. EDITORIAL: Just bad weather Not surprisingly, the "Democratic People's Republic" of The hermit, Stalinist regime is run by the psychopath Kim Jong Il. The nation's people have little contact with the outside world. "Business freedom, investment freedom, trade freedom, financial freedom, freedom from corruption and labor freedom are nonexistent," reports the Heritage Foundation. Might any of this have to do with the fact that many of the country's 22.5 million people live in abject poverty on the verge of starvation? You wouldn't know it from some news accounts. On Monday, McClatchy Newspapers moved a dispatch from In response, the Then we learn that the government-controlled North Korean press blames the problem "on factors such as unseasonably cold spring weather." And "experts" say the country is in a bind "for several reasons, including flooding that ravaged the western coastal plains nine months ago, chronic fertilizer shortages and steadily falling harvests." Miraculously, just below the 38th parallel, prosperous Must just be the weather.
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The following passages also deny
certain causal connections, based on applications of Mill’s methods.
Identify the causal claim that is being refuted, as well as the method or
methods used to refute it. Also, if they assert a causal claim, identify
it as well as the method used to support it. 1. World hunger has precious little to do with droughts or
"crop failures," and a whole lot to do with the economic systems
under which people live. Neither Why is there no starvation in 2. The people of These tickets, which cost drivers $159 per violation, produce tens of thousands of dollars in revenue every month for the county and 23 participating cities. The cameras were installed with the promise that they'd hold reckless drivers accountable and reduce the number of broadside collisions caused by red-light runners. Motorists weren't told that cameras would also be watching for rolling right turns, which almost never result in accidents and carry nearly no risk of causing a death or serious injury. (LVRJ Editorial, 23 May 2008) 3. Cattle weren't the problem, Mr. Pappas has always insisted. In fact, cattlemen formerly reduced the populations of predators including the coyote and the raven, which benefited tortoise populations. "But now they say the way to protect the tortoise is to fence off the land and not let the ranchers and the hunters in, when the biggest tortoise populations we ever had were in the '50s and '60s, when you had plenty of ranching, and plenty of hunting, and plenty of predator control," Mr. Pappas insists. (LVRJ, 14 May 2008) 4. “…the immigration and spending issues can't be causing the drop in Bush's poll numbers among Republicans because he had the same immigration plan in 2004 and spent like a sailor in his first term and still had over 90 percent support during that election year.: (Slate Magazine, May 10, 2006)
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