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Cause and Effect

by Placement FactoryPlacement Factory
Type: NoteSpecialization: Logical ReasoningOffline Downloads: 79Views: 1913Uploaded: 2 months ago

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C hapter Seven: Cause and Effect Reasoning What is Causality? When examining events, people naturally seek to explain why things happened. This search often results in cause and effect reasoning, which asserts or denies that one thing causes another, or that one thing is caused by another. On the GMAT, cause and effect reasoning appears in many Critical Reasoning problems, often in the conclusion where the author mistakenly claims that one event causes another. For example: Last week Apple announced a quarterly deficit and the stock market dropped 10 points. Thus, Apple’s announcement must have caused the drop. Like the above conclusion, most causal conclusions are flawed because there can be alternate explanations for the stated relationship: another cause could account for the effect; a third event could have caused both the stated cause and effect; the situation may in fact be reversed; the events may be related but not causally; or the entire occurrence could be the result of chance. In short, causality occurs when one event is said to make another occur. The cause is the event that makes the other occur; the effect is the event that follows from the cause. By definition, the cause must occur before the effect, and the cause is the “activator” or “ignitor” in the relationship. The effect always happens at some point in time after the cause. How to Recognize Causality A cause and effect relationship has a signature characteristic—the cause makes the effect happen. Thus, there is an identifiable type of expression used to indicate that a causal relationship is present. The list on the following page contains a number of the phrases used by the makers of the GMAT to introduce causality, and you should be on the lookout for those when reading Critical Reasoning stimuli. Chapter Seven: Cause and Effect Reasoning Causality is the most-tested logical concept in GMAT Critical Reasoning stimuli. The second most tested concept is Numbers and Percentages, which will be addressed in Chapter Twelve. As mentioned before, this is a book about GMAT logic, not general philosophy. Therefore, we will not go into an analysis of David Hume’s Inquiry or Mill’s Methods (both of which address causality) because although those discussions are interesting, they do not apply to the GMAT. 133
The following terms often introduce a cause and effect relationship: Be sure to memorize this list! caused by because of responsible for reason for leads to induced by promoted by determined by produced by product of played a role in was a factor in is an effect of Because of the variety of the English language, there are many alternate phrases that can introduce causality. However, those phrases would all have the similar characteristic of suggesting that one event made another occur. Causality in the Conclusion versus Causality in the Premises In the GMAT world, when a cause and effect statement appears as the conclusion, the conclusion is flawed. In the real world that may not be the case because a preponderance of evidence can be gathered or visual evidence can be used to prove a relationship. Causal statements can be found in the premise or conclusion of an argument. If the causal statement is the conclusion, then the reasoning is flawed. If the causal statement is the premise, then the argument may be flawed, but not because of the causal statement. Because of this difference, one of the critical issues in determining whether flawed causal reasoning is present is identifying where in the argument the causal assertion is made. The classic mistaken cause and effect reasoning we will refer to throughout this book occurs when a causal assertion is made in the conclusion, or the conclusion presumes a causal relationship. Let us examine the difference between an argument with a causal premise and one with a causal conclusion. This is an argument with a causal conclusion: Premise: In North America, people drink a lot of milk. Premise: There is a high frequency of cancer in North America. Conclusion: Therefore, drinking milk causes cancer. In this case, the author takes two events that occur together and concludes that one causes the other. This conclusion is in error for the reasons discussed on the first page of this chapter. If a causal claim is made in the premises, however, then no causal reasoning error exists in the argument (of course, the argument may be flawed in other 134 The PowerScore GMAT Critical Reasoning Bible
ways). As mentioned previously, the makers of the GMAT tend to allow premises to go unchallenged (they are more concerned with the reasoning that follows from a premise) and it is considered acceptable for an author to begin his argument by stating a causal relationship and then continuing from there: Premise: Drinking milk causes cancer. Premise: The residents of North America drink a lot of milk. Conclusion: Therefore, in North America there is a high frequency of cancer among the residents. The second example is considered valid reasoning because the author takes a causal principle and follows it to its logical conclusion. Generally, causal reasoning occurs in a format similar to the first example, but there are GMAT problems similar to the second example. Situations That Can Lead to Errors of Causality There are two scenarios that tend to lead to causal conclusions in Critical Reasoning questions: 1. One event occurs before another When one event occurs before another event, many people fall into the trap of assuming that the first event caused the second event. This does not have to be the case, as shown by the following famous example: Every morning the rooster crows before the sun rises. Hence, the rooster must cause the sun to rise. The example contains a ludicrous conclusion, and shows why it is dangerous to simply assume that the first event must have caused the second event. 2. Two (or more) events occur at the same time When two events occur simultaneously, many people assume that one event caused the other. While one event could have caused the other, the two events could be the result of a third event, or the two events could simply be correlated without one causing the other. The following example shows how a third event can cause both events: The consumption of ice cream has been found to correlate with the murder rate. Therefore, consuming ice cream must cause one to be more likely to commit murder. Chapter Seven: Cause and Effect Reasoning If you have taken a logic course, you will recognize the first scenario produces the Post Hoc, Ergo Propter Hoc fallacy. In the second example, the two events could simply be correlated. A positive correlation is a relationship where the two values move together. A negative correlation is one where the two values move in opposite directions, such as with age and eyesight (the older you get, the worse your eyesight gets). 135
As you might imagine, the conclusion of the example does not have to be true (yes, go ahead and eat that Ben and Jerry’s!), and the two events can be explained as the effects of a single cause: hot weather. When the weather is warmer, ice cream consumption and the murder rate tend to rise (this example is actually true, especially for large cities). The Central Assumption of Causal Conclusions Understanding this assumption is absolutely critical to your GMAT success. The makers of the test will closely examine your knowledge of this idea, especially in Strengthen and Weaken questions. Understanding the assumption that is at the heart of a causal conclusion is essential to knowing why certain answers will be correct or incorrect. Most students assume that the GMAT makes basic assumptions that are similar to the real world; this is untrue and is a dangerous mistake to make. When we discuss causality in the real world, there is an inherent understanding that a given cause is just one possible cause of the effect, and that there are other causes that could also produce the same effect. This is reasonable because we have the ability to observe a variety of cause and effect scenarios, and experience shows us that different actions can have the same result. The makers of the GMAT do not think this way. When a GMAT speaker concludes that one occurrence caused another, that speaker also assumes that the stated cause is the only possible cause of the effect and that consequently the stated cause will always produce the effect. This assumption is incredibly extreme and far-reaching, and often leads to surprising answer choices that would appear incorrect unless you understand this assumption. Consider the following example: Premise: Average temperatures are higher at the equator than in any other area. Premise: Individuals living at or near the equator tend to have lower per-capita incomes than individuals living elsewhere. Conclusion: Therefore, higher average temperatures cause lower per-capita incomes. This argument is a classic flawed causal argument wherein two premises with a basic connection (living at the equator) are used as the basis of a conclusion that states that the connection is such that one of the elements actually makes the other occur. The conclusion is flawed because it is not necessary that one of the elements caused the other to occur: the two could simply be correlated in some way or the connection could be random. In the real world, we would tend to look at an argument like the one above and think that while the conclusion is possible, there are also other things that 136 The PowerScore GMAT Critical Reasoning Bible

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